Print Multi - NFPA Draft_agenda _08-12.pdfVijay Panjwani, Husky Injection Molding Inc. Add new text to read as follows: An electronic device rated 30A and less connected in series

Report on Proposals – June 2014 NFPA 79_______________________________________________________________________________________________79- Log #106 EEI-AAA

_______________________________________________________________________________________________Paul Dobrowsky, Holley, NY

Delete the parenthetical terms used to describe IEC terms that follow terms used in NFPA 79 suchas "protective bonding". Add information in Annex A explaining the IEC term. Also delete terms in Chapter three thatonly define parenthetical terms in the standard.

The present use of parenthetical terms is confusing to the user of the standard. The terms describeddo not always match the term they follow as many times they are not directly interchangeable. The base for NFPA 79 isthe NEC and its used should be based on the terms from the NEC where they are provided.

_______________________________________________________________________________________________79- Log #8 EEI-AAA

_______________________________________________________________________________________________Mark R. Hilbert, MR Hilbert Electrical Inspections & Training

Revise to read:1.3.1.1 2 When changes other than repairs are made to machines that do not comply with the provisions of this

standard, the changes shall conform to the provisions of this standard.The section as currently located does not comply with the NFPA Manual of Style which states that all

subdivisions shall contain at least two subdivisions. This change is the result of the Editorial Task Group review of the2012 document for compliance with 1.8.1 of the NFPA Manual of Style.

_______________________________________________________________________________________________79- Log #10 EEI-AAA


Revise to read:1.3.2 3 This standard shall not apply to the following:

This section is being renumbered as a result of the Editorial Task Group recommendations to align the2015 Edition of NFPA 79 with 1.8.1 of the NFPA Manual of Style.

_______________________________________________________________________________________________79- Log #33 EEI-AAA

_______________________________________________________________________________________________George M. Schreck, Komatsu America Industries, LLC

Add new text to read:NFPA 77, Recommended Practice on Static Electricity, 2007.

Source of material on other proposals.

1Printed on 7/18/2012


_______________________________________________________________________________________________John F. Bender, UL LLC

Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096.ANSI/UL 50, 2007.ANSI/UL 508, 1999, Revised 2010.UL 508A, 2001, Revised 2010.ANSI/UL 870, 2008.ANSI/UL 1063, 2006.ANSI/UL 1581, 2001, Revised 2009 2011.

Update referenced standards to most recent edition as indicated.

_______________________________________________________________________________________________79- Log #25 EEI-AAA

_______________________________________________________________________________________________James H. Maxfield, City of Dover Fire & Rescue / Rep. IAEI

Revise to read: 3.1 General. The definitions contained in this chapter shall apply to the terms used in this standard. Where terms are

not defined in this chapter or within another chapter, they shall be defined using their ordinarily accepted meaningswithin the context in which they are used. Merriam-Webster’s Collegiate Dictionary, 11th edition, shall be the source forthe ordinarily accepted meaning.

The change reflects the proper dictionary to be referenced when a term is not defined in the document.This editorial change is necessary to comply with section 2.3.1.3.1 of the Manual of Style for NFPA TechnicalCommittee Documents.

_______________________________________________________________________________________________79- Log #34 EEI-AAA


Add a new section to read:Bonding by attaching a grounding conductor to the equipmetn or device with bolts or

screws, where all paint and dirt are removed from the joint surface, shallb e considered to be effectively grounded.No explanation of what is considered "effectively grounded". Ground bond connection made by screw

threads for fastening a connection over an insulating surface (i.e., paint) or other non-conductive material is notsufficient.



_______________________________________________________________________________________________Vijay Panjwani, Husky Injection Molding Inc.

Add new text to read as follows:An electronic device rated 30A and less connected in series with an upstream listed

circuit breaker that have been tested together to work in coordination to provide branch circuit overcurrent protection tothe circuit(s).

At present, the only branch circuit protective devices allowed are circuit breakers (UL 489) and certainfuses (UL248 except UL 248-14). Due to the advances in technology, solid state devices can perform in the same way as branch circuit protective

devices. Solid state overcurrent protection devices are already allowed as part of servo drives and as circuit breaker tripunits, as long as they have been tested, evaluated and found suitable for that particular purpose. By allowing analternate solution for branch circuit protection, state of the art can evolve under specific and controlled conditions.There are certain problems in using the branch circuit protective devices, especially where multiple small loads

(25-200) that require small gauge wiring (16-18 AWG).1) By allowing 16 and 18 AWG wiring as per clause 12.6, repetitive circuits lend themselves to be designed on printed

circuit boards. There are only a few branch circuit protective devices that could be installed on the printed circuit boards.The alternate, off board breakers and fuses occupy a lot of space, especially where many small current resistanceheating loads are considered.2) Where a piece of equipment has many small branch circuits, large circuit breakers or fuses may be undesirable. The

size of the actual equipment may be much smaller than the control equipment as the protective devices do not reduce insize (unlike heaters, connectors, wiring, etc.). As a result of this need for compactness, some products have beendesigned with supplementary fuses or supplementary protectors for these applications. These devices do not includeadequate features or ratings such as rejection for various characteristics /type fuses, isolation, interrupting ratings, notrupturing, not failing closed.3) The present branch circuit protective devices that are allowed for 16AWG and 18AWG do not adequately protect the

semiconductor switches that are used on printed circuit boards and are widely used for controlling multiple smallamperage heating loads.4) In our specific case, there are tools with many temperature control zones. The zones of interest have low currents

(typically < 2 Amps), and there are many such zones (25 -200 zones). These lend themselves to the 18AWG wires evenwith group derating. Using 14AWG wires is not possible due to limited connector space. The nature of the loads is thatthey do not fail in overload; instead they fail open or short circuit. The nature of the power circuitry in the application alsolimits the available short circuit to levels that can be addressed safely in the circuit design.We propose that an alternate protection be accepted for specific applications. The design, performance and

manufacturing of this class of protection would be overseen by an NRTL in order to ensure that it is safe. The design,performance, construction, and testing requirements can be drawn from various standards.1. Performance (calibration, tripping characteristics, temperature rise, thermal withstand) as per UL 489.2. Construction (clearance and creepage, materials, pollution degree, corrosion protection) as per UL 508C or UL 840.3. Testing (risk of electric shock, risk of fire, printed wiring boards, field wiring terminals, dielectric voltage withstand

test, breakdown of components test, short circuit test) as per UL508 or UL61010.4. Design and verification processes (EMC testing, failure analysis) as per ISO13849 or IEC62061.5. Manufacturing and production line tests (verification of functionality, in-coming component screening, burn-in tests

that vary in conditions, and diagnostic tests) as per UL 508C.




Revise to read: 3.3.3.1 4 Actuator, Machine. A power mechanism used to effect motion of the machine.

The section as currently numbered does not comply with the NFPA Manual of Style which states thatall subdivisions shall contain at least two subdivisions. This change is the result of the Editorial Task Group review of the2012 document for compliance with 1.8.1 of the NFPA Manual of Style. This section is being renumbered as a result ofthe Editorial Task Group recommendations to align the 2015 Edition of NFPA 79 with 1.8.1 of the NFPA Manual of Style.

_______________________________________________________________________________________________79- Log #47 EEI-AAA

_______________________________________________________________________________________________Daniel R. Neeser, Cooper Bussmann

Add new text to read as follows:3.3.4 Adjacent. Sharing a common wall, partition, or barrier.

This term is used in several sections of the Standard, but is not currently defined in the Standard. Thedefinition proposed is from the NFPA Glossary of terms. This is additionally defined in NFPA 820, therefore, it would beappropriate to add to other standards such as NFPA 79 to add clarity.

_______________________________________________________________________________________________79- Log #115 EEI-AAA


Delete the following text:3.3.34 Earth. See 3.3.47, Ground.

Delete this term as it is already used in the definition of "ground" and is unnecessary.

_______________________________________________________________________________________________79- Log #109 EEI-AAA


Delete the following text:3.3.50 Grounding Conductor. A conductor used to connect equipment or the grounded circuit of a wiring system to a

grounding electrode or electrodes.Delete this definition. The term has been deleted in the 2011 NEC and replaced with either the

equipment grounding conductor, bonding conductor or grounding electrode conductor. NFPA 79 should correspond withthe use of terms in the NEC where possible.

_______________________________________________________________________________________________79- Log #110 EEI-AAA


Add an asterisk to 3.3.51*.This is a companion input to delete parenthetical terms in NFPA 79. Add the information in Annex A to

describe the terms sometimes used in place of the term equipment grounding conductor.




Add new text to read as follows:3.3.56 Industrial Control Panel. An assembly of two or more components consisting of one of the following:(1) Power circuit components only, such as motor controllers overload relays, fused disconnect switches, and circuit

breakers(2) Control circuit components only, such as pushbuttons, pilot lights, selector switches, timers, switches, control relays(3) A combination of power and control circuit componentsThese components, with associated wiring and terminals, are mounted on or contained within an enclosure or mounted

on a subpanel. The industrial control panel does not include the controlled equipment.This term is used in the Standard but a definition does not exist. Adding this definition will add clarity

to the Standard. This is the definition of industrial control panel from NEC 409.2.

_______________________________________________________________________________________________79- Log #46 EEI-AAA


Add new text to read as follows:3.3.72 Overcurrent Protective Device, Branch-Circuit. A device capable of providing protection for service, feeder, and

branch circuits and equipment over the full range of overcurrents between its rated current and its interrupting rating.Branch-circuit overcurrent protective devices are provided with interrupting ratings appropriate for the intended use butno less than 5000 amperes.

This term is used in several sections of the Standard, but is not currently defined. This definition isfrom the 2011 NEC and will provide the proper definition for this term.

_______________________________________________________________________________________________79- Log #108 EEI-AAA


Delete the following text:3.3.74 Positive Opening Operation (of a contact element). The achievement of contact separation as the direct result

of a specified movement of the switch actuator through nonresilient members (e.g., not dependent upon springs).Delete this definition. Direct Opening operation (3.3.30) is used in the standard. There should not be

two terms essentially identically defined.




Delete the following text:3.3.77* Protective Bonding Circuit. The whole of the protective conductors and conductive parts used for protection

against electric shock in the event of an insulation failure.Delete this term as it is only used as a parenthetical term. Using multiple terms in the same document

to mean similar things adds confusion. The NEC is the base document and its terms should be used in NFPA 79 ifpossible.

_______________________________________________________________________________________________79- Log #113 EEI-AAA


Delete the following text:3.3.78 Protective Conductor. A conductor required by some measures for protection against electric shock for

electrically connecting exposed conductive parts, extraneous conductive parts, or main earthing terminal.Delete this term as it is only used as a parenthetical term. Using multiple terms in the same document

to mean similar things adds confusion. The NEC is the base document and its terms should be used in NFPA 79 ifpossible.

_______________________________________________________________________________________________79- Log #44 EEI-AAA


Delete the following text:3.3.98 Subassembly. An assembly of electrical devices connected together that forms a simple functional unit.

Subassembly is a defined term, but is not currently used in the requirements of the standard. As suchthe definition is not needed.

_______________________________________________________________________________________________79- Log #43 EEI-AAA


Revise text to read as follows:3.3.100* Supplementary Overcurrent Protective Device, Supplementary. A device intended to provide limited

overcurrent protection for specific applications and utilization equipment such as found within industrial machines. Thislimited protection is in addition to the protection provided in the required branch circuit by the branch circuit overcurrentprotective device.

This term is revised to correlate with how it is shown in the NEC. The definition remains slightlymodified from the definition in the NEC with regards to types of utilization equipment to be relevant to industrialmachines. Another proposal has been submitted which defines “overcurrent protective device, branch-circuit” ascurrently defined in the NEC. The numbering will need to be revised based on the change to the term.




Revise to read:4.4.2.1 2 Transient suppression, isolation, or other appropriate means shall be provided where the equipment

generates electrical noise or transients, which can affect the operation of equipment.The section as currently numbered does not comply with the NFPA Manual of Style which states that

all subdivisions shall contain at least two subdivisions. This change is the result of the Editorial Task Group review of the2012 document for compliance with 1.8.1 of the NFPA Manual of Style.

_______________________________________________________________________________________________79- Log #90 EEI-AAA

_______________________________________________________________________________________________Jay Tamblingson, Rockwell Automation

Add new text to read:Exception: Where an on-board power source supplies only control circuits, other means to denergize its output(s) shall

be permitted (e.g. control rated switch, EPO input interlock) .It is becoming increasingly common to utilize UPS within control panels to protect control equipment

from brief interruptions of power and provide orderly shutdown of computer based equipment. These devices oftenincorporate power switches or designated power off interlock inputs to deenergize the output circuits. The revisedchange would recongnize use of these functions.

_______________________________________________________________________________________________79- Log #107 EEI-AAA


Add new text to read: Exception: Communication and remote control and signaling circuits shall not be required to be provided with a supplycircuit disconnecting means.

Section 5.1.1 includes "electronic circuits" in the description. it is not practical or necessary to providea disconnecting means for these limited energy type of circuits.

It is intended that the exception follow list item 3 but not to be a list item (4) as the input process automatically includedit.




Revise text to read:Exception (1) : Externally mounted supply circuit disconnecting means, whether interlocked or not interlocked with the

control enclosure, supplying machines totaling 2 hp or less shall be permitted to be mounted up to 6 m (20 ft) away fromthe enclosure providing that the disconnecting means is in sight from and readily accessible to the operator.Exception(2) : A supply circuit disconnecting means mounted in a separate enclosure and interlocked with the control

enclosure(s) it supplies shall be permitted to be mounted up to 6 m (20 ft) away providing that the disconnecting meansis in sight from the control enclosure(s) and readily accessible to the operator.

The new exemption language will broaden permitted use of a separated mounted supplydisconnecting means. Due to concerns of arc-flash and shock hazards, it is becoming increasingly desirable to locatethe supply disconnecting means in a separate enclosure to ensure that absolutely no power is present in the main panelduring maintenance activities after the disconnecting means is turned off and lockout procedures applied. However, as itis now common for the control enclosure(s) to be located on a machine rather than a freestanding separate enclosure, itis often not possible to mount the supply disconnect immediately adjacent to the main enclosure.

_______________________________________________________________________________________________79- Log #64 EEI-AAA

_______________________________________________________________________________________________Noel Williams, Noel Williams Consulting

Revise to read:5.3.1.3 The supply circuit disconnecting means other than attachment plugs and receptacles shall be mounted within

the control enclosure or immediately adjacent thereto.Exception No 1: Externally mounted supply circuit disconnecting means, whether interlocked or not interlocked with the

control enclosure, supplying machines totaling 2 hp or less shall be permitted to be mounted up to 6 m (20 ft) away fromthe enclosure providing that the disconnecting means is in sight from and readily accessible to the operator.Exception No 2: Where the risk assessment required by Section 4.1 determines that operation of a disconnecting

means is an increased hazard without first bringing the machine to a complete stop using a Category 1 or 2 controlledstop, the disconnect may be located remotely if the requirements of 6.2.4 and 16.2.6 are met.

The suggested condition is already anticipated by other requirements as noted in the proposal.However, the permission to locate or conditions for locating a disconnect remotely are not clearly stated. Many largemachines require complex control procedures to bring the machine operation safely to a halt. One machine (meeting thedefinition of industrial machine) this author has seen is supplied by three unit substations and the only disconnect for theentire machine is a substation disconnect that supplies the three unit substations. Many other machines have a totalhorsepower rating that exceeds the capacity of any load-break disconnect and include multiple control panels where thedisconnection of any individual panel without a controlled stop can greatly increase hazards. The requirementsregarding disconnecting means should recognize special conditions where the required risk analysis precludes theoperation of a local disconnect.




Revise text to read as follows:5.3.1.4 Each supply circuit disconnecting means mounted within or immediately adjacent to the control enclosure shall

be interlocked with the control enclosure in accordance with 6.2.3. Where the supply circuit disconnecting means is notwithin or immediately adjacent to the control enclosure, or where the supply disconnecting means is an attachment plugand receptacle, the control enclosure is not required to comply with 6.2.3 but shall comply with 6.2.4 and a safety signshall be provided in accordance with Section 16.2.

This change helps clarify that if the supply circuit disconnecting means is not located within orimmediately adjacent to the control enclosure is not required to comply with 6.2.3, provided compliance with 6.24 and16.2. Immediately was added to correlate with 5.3.1.3.Where this is of primary concern is where additional machine electrical enclosures are located downstream of the

supply circuit disconnect, which could be part of the machine industrial control panel or a separately mounteddisconnect. Where this occurs, the downstream industrial control panel or electrical enclosures should not have tocomply with 6.2.3, provided they do comply with 6.2.4 and 16.2 (specifically 16.2.6).

_______________________________________________________________________________________________79- Log #13 EEI-AAA


Revise to read: 5.3.3.2.1 3 In addition to the requirements in 5.3.3.2, an additional switching device on the machine shall be provided

for routine power switching operations of the machine on and off.The section as currently numbered does not comply with the NFPA Manual of Style which states that


_______________________________________________________________________________________________79- Log #103 EEI-AAA

_______________________________________________________________________________________________David Fisher, Rockwell Automation

Revise the title to read:Protection from Electrical Hazards Electric Shock

The ccurrent text is misleading in that there are no protective measures in Chapter 6 oher than thosefor electric shock.

_______________________________________________________________________________________________79- Log #24 EEI-AAA


Revise to read: 6.1 General. Electrical equipment shall provide protection of persons from electric shock, from direct and indirect

contact, and from shall be marked to warn qualified person(s) of a potential arc-flash hazards.Current language could be interpreted to require that the equipment must be designed to protect

person(s) from arc flash hazards.The revised language coincides with the committee discussions from the ROC meeting in Milwaukee, WI to warn a

person(s) of arc flash hazard potential with the appropriate warning sign(s) in accordance with section 16.2.




Revise text to read: 6.1 General. Electrical equipment shall provide protection of persons from electric shock, from direct and indirect

contact, and from arc-flash hazards.The deletion of arc-flash hazards text is necessary because there are no protetctive measures

addressing arc-ash hazards in Capter 6.

_______________________________________________________________________________________________79- Log #31 EEI-AAA


Add new text to read:Where workers are exposed to a known process in which static electric discharge potential exists, the workers shall be

grounded through a resistance that limits the current to ground to less than 3mA.Worker on a “grounded machine” in contact with the machine frame (elevated platform maintenance

area), received a substaintial shock when “touching” replacement equipment being brought to the machine by a fork lift(the forklift contained the static charge).

_______________________________________________________________________________________________79- Log #14 EEI-AAA


Revise to read: 6.2.2.1 3 Direct Contact from Outside an Enclosure. Equipment enclosures and enclosure openings shall meet the

requirements of ANSI/UL 508, UL 508A, ANSI/UL 50, or NEMA 250. (See Figure 6.2.3.)Figure 6.2.2.1 3 Jointed Test Finger.

(Figure unchanged)

Exception : In the absence of a rated enclosure, the determination of the suitability of an enclosure as protection fromelectrical shock shall be determined by using a test finger as described in Figure 6.2.2.1 3 The test finger shall beapplied, with only minimal force, in every opening in the enclosure after removal of all parts of the enclosure that arecapable of being removed without the use of a tool. The test finger shall not encounter live parts in any direction.

The section as currently numbered does not comply with the NFPA Manual of Style which states thatall subdivisions shall contain at least two subdivisions. This change is the result of the Editorial Task Group review of the2012 document for compliance with 1.8.1 of the NFPA Manual of Style.



_______________________________________________________________________________________________Glen Kampa, Pentair Technical Products

Revise text to read as follows:(3)* Prevent closing of the disconnecting means while the enclosure master door is open, unless an interlock is

operated by deliberate actionFPN: For multi-door disconnects, the master door is the door typically closest to the disconnect. The master door

interlocks with the other door(s) such that the other doors cannot be opened until the master door is opened. Typicallyonly the master door interlocks directly with the disconnect operator such that the disconnect cannot be closed until themaster door is closed.

This is to clarify commonly available multi-door disconnect enclosure operation. Currently the commonlegacy multi-door disconnect enclosure do not interlock all doors with the disconnect operator such that the operatorcannot be closed (turned on) until all doors are closed. Only the first (ie master door) interlocks with the operator interms of closing the operator. The master door interlocks with all other doors such that the other doors can only beopened when the master door is open.

_______________________________________________________________________________________________79- Log #9 EEI-AAA


Revise to read:6.4.1.1 2 PELV circuits shall satisfy all of the following conditions:


_______________________________________________________________________________________________79- Log #23 EEI-AAA


Revise to read:6.6 Protection Against Arc Flash. Arc Flash Hazard Warning. A safety sign shall be provided in accordance with

16.2.3.The change in the title of the section will clarify the purpose of this section. The purpose is to require

an arc flash warning sign to warn qualified person(s) of a potential arc flash hazard. It is not to provide protection againstan actual arc flash.

_______________________________________________________________________________________________79- Log #86 EEI-AAA


Revise text to read:6.6 Protection Against Arc Flash Arc-Flash Hazard Warning. A safety sign shall be provided in accordance with 16.2.3.

The revised language properly indicates that requirements consist only of warning of potentialarc-flash hazards. This language is consistent with actions taken in the 2011 NEC where the title of section 110.16 waschanged to identical language.




Add new text to read:All conductive auxiliary equipment, associated with a process cell, even un-powered, shall be bonded so that all

equipment of that cell will be at the same electrical potential, the voltage differences between the separate auxiliaryitems of equipment is zero (0).

Static charge build up in a piece of unpowered equipment, due to plastic web motion, built to a voltagepotential to cause an arc from that unpowered equipment to the powered, grounded equipment that is was next to.

_______________________________________________________________________________________________79- Log #32 EEI-AAA


Add new text to read:Static electrical discharge.

Substantial static electrical discharge into a machine system utilizing electronic devices and controlsystems (PLC/VFD/Servo Drives) can cause electronic based equipment damage, and changes to control systemprogramming logic that could create an unexpected hazard to machine operator(s).

_______________________________________________________________________________________________79- Log #55 EEI-AAA


Revise text to read as follows:7.2.1.2 All overcurrent protective devices shall be selected and applied with proper consideration being given to, but

not limited to, the following:(1) System maximum available fault current at the point of application(2) Interrupting rating of the overcurrent protective device(3) Voltage rating of the system(4) Load and circuit characteristics

(a) Normal operating current(b) Inrush characteristics(c) Thermal withstand capability (I 2t)(d) Magnetic withstand capability (Ip)

(5) Current-limiting ability of the overcurrent protective device(6) Coordination of the overcurrent protective devices to each other

Addition of “overcurrent” adds clarity.




Revise text to read:7.2.4.2.5 Control circuit conductors supplied by the secondary side of a single-phase transformer having a 2-wire

(single-voltage) secondary shall be considered protected by overcurrent protection provided on the primary (supply) sideof the transformer, if this protection is in accordance with 7.2.7 and does not exceed the value determined by multiplyingthe secondary conductor ampacity by the secondary-to-primary voltage ratio. Transformer secondary conductors (otherthan 2-wire) are shall not considered be considered to be protected by the primary overcurrent protective device.

The change makes the document clear that conductors other than those from 2 wire secondarytransformers are not permitted to be protected by the primary overcurrent protective device. The proposed languagechange is also consistent with 240.4(f) of NFPA 70. Lastly, the change provides mandatory text in accordance with2.3.3.1 and 2.3.3.2 of the Manual of Style which does not permit non mandatory text in the body of the standard andrequires the terms shall and shall not to be used to indicate mandatory requirements.

_______________________________________________________________________________________________79- Log #15 EEI-AAA


Revise to read:7.2.7.1 Transformers for motor control circuits shall be protected in accordance with Article 430, Part VI, of NFPA 70.

Transformers for other than motor control circuits shall be protected in accordance with Article 450, Part I, of NFPA 70.The section as currently numbered does not comply with the NFPA Manual of Style which states that


_______________________________________________________________________________________________79- Log #54 EEI-AAA


Revise text to read as follows(e) The conductor terminates in a single branch circuit– rated overcurrent protective device.(c) The conductor is not over 7.5 m (25 ft) long, and the conductor terminates in a single branch circuit–rated

overcurrent protective device.Deletion of “rated” and addition of “overcurrent” adds clarity.

_______________________________________________________________________________________________79- Log #16 EEI-AAA


Revise to read:7.2.10.1.1 2 A listed self-protected combination controller shall be permitted in lieu of the devices specified in Table

7.2.10.1 for branch circuit and overload protection of a single motor circuit. Where the controller has an adjustable,instantaneous trip setting, the setting shall not exceed 1300 percent of full-load motor current for other than Design Benergy efficient motors and not more than 1700 percent of full-load motor current for Design B energy efficient motors.





Revise text to read as follows(2) The rating of the branch-circuit short-circuit and ground-fault protective device marked on any of the controllers is

not exceeded. The short-circuit and ground-fault protection is provided by a single inverse time circuit breaker or singeset of fuses.

This addition clarifies the type of protective device required and correlates with NEC 430.53(A) andsimilar requirements in NFPA 79 7.2.10.4. Note that in NEC 430.53 a last sentence was added to clarify that an inversetime circuit breaker or fuses are required in case of 430.53(A).

_______________________________________________________________________________________________79- Log #52 EEI-AAA


Revise text to read as follows:7.2.10.3 Where the branch-circuit short-circuit and ground-fault protective device is selected not to exceed that allowed

by 7.2.10.1 for the smallest rated motor, two or more motors or one or more motors and other load(s), with each motorhaving individual overload protection, shall be permitted to be connected to a branch circuit where it can be determinedthat the branch-circuit short-circuit and ground-fault protective device will not open under severe normal conditions ofservice that might be encountered. The short-circuit and ground-fault protection is provided by a single inverse timecircuit breaker or singe set of fuses.

This addition clarifies the type of protective device required and correlates with NEC 430.53(B) andsimilar requirements in NFPA 79 7.2.10.4. Note that in NEC 430.53 a last sentence was added to clarify that an inversetime circuit breaker or fuses are required in case of 430.53(B).



_______________________________________________________________________________________________Vijay Panjwani, Husky Injection Molding Inc.

Add new text to read as follows:Exception: A listed resistance heating protector used in coordination with its intended feeder circuit breaker. Multiple

resistance heating protectors may be used to feed multiple loads with a single feeder circuit breaker in accordance with7.2.11.2.

At present, the only branch circuit protective devices allowed are circuit breakers (UL 489) and certainfuses (UL248 except UL 248-14). Due to the advances in technology, solid state devices can perform in the same wayas branch circuit protective devices. Solid state overcurrent protection devices are already allowed as part of servodrives and as circuit breaker trip units, as long as they have been tested, evaluated and found suitable for that particularpurpose. By allowing an alternate solution for branch circuit protection, state of the art can evolve under specific andcontrolled conditions.There are certain problems in using the branch circuit protective devices, especially where multiple small loads

(25-200) that require small gauge wiring (16-18 AWG).1) By allowing 16 and 18 AWG wiring as per clause 12.6, repetitive circuits lend themselves to be designed on printed

circuit boards. There are only a few branch circuit protective devices that could be installed on the printed circuit boards.The alternate, off board breakers and fuses occupy a lot of space, especially where many small current resistanceheating loads are considered.2) Where a piece of equipment has many small branch circuits, large circuit breakers or fuses may be undesirable. The

size of the actual equipment may be much smaller than the control equipment as the protective devices do not reduce insize (unlike heaters, connectors, wiring, etc.). As a result of this need for compactness, some products have beendesigned with supplementary fuses or supplementary protectors for these applications. These devices do not includeadequate features or ratings such as rejection for various characteristics /type fuses, isolation, interrupting ratings, notrupturing, not failing closed.3) The present branch circuit protective devices that are allowed for 16AWG and 18AWG do not adequately protect the

semiconductor switches that are used on printed circuit boards and are widely used for controlling multiple smallamperage heating loads.4) In our specific case, there are tools with many temperature control zones. The zones of interest have low currents

(typically < 2 Amps), and there are many such zones (25 -200 zones). These lend themselves to the 18AWG wires evenwith group derating. Using 14AWG wires is not possible due to limited connector space. The nature of the loads is thatthey do not fail in overload; instead they fail open or short circuit. The nature of the power circuitry in the application alsolimits the available short circuit to levels that can be addressed safely in the circuit design.We propose that an alternate protection be accepted for specific applications. The design, performance and

manufacturing of this class of protection would be overseen by an NRTL in order to ensure that it is safe. The design,performance, construction, and testing requirements can be drawn from various standards.1. Performance (calibration, tripping characteristics, temperature rise, thermal withstand) as per UL 489.2. Construction (clearance and creepage, materials, pollution degree, corrosion protection) as per UL 508C or UL 840.3. Testing (risk of electric shock, risk of fire, printed wiring boards, field wiring terminals, dielectric voltage withstand

test, breakdown of components test, short circuit test) as per UL508 or UL61010.4. Design and verification processes (EMC testing, failure analysis) as per ISO13849 or IEC62061.5. Manufacturing and production line tests (verification of functionality, in-coming component screening, burn-in tests

that vary in conditions, and diagnostic tests) as per UL 508C.




Revise to read:7.3.1 General. Overload devices shall be provided to protect each motor, motor controller, and branch-circuit

conductor against excessive heating due to motor overloads or failure to start.The section as currently numbered does not comply with the NFPA Manual of Style which states that


_______________________________________________________________________________________________79- Log #42 EEI-AAA


Revise text to read as follows:7.8 Protection Against Overvoltages Due to Lightning and Switching Surges.7.8.1 Overvoltage Surge Protection Devices (SPDs). SPDs Protective devices shall be permitted to be provided to

protect against the effects of overvoltages due to lightning or switching surges.7.8.2 Lightning Overvoltage SuppressionConnections. Where provided, SPDs devices for the suppression for

overvoltages shall be connected in accordance with product markings and installation instructions.7.8.3 Surge Switching Overvoltage SuppressionEquipment Protection. Where provided, SPDs devices for the

suppression of overvoltages due to switching surges shall be connected across the terminals of all equipment requiringsuch protection.7.8.4 SPD Type and Location. The type of SPD provided shall be suitable for the installation location of the industrial

machinery. Where the SPD is connected on the line side of the service entrance overcurrent protective device, Type 1SPDs shall be provided. Where the industrial machinery is located on the loadside of the service disconnect overcurrentprotection, feeder circuit, or separately derived system, Type 1 or Type 2 SPDs shall be provided. Where Type 2 SPDsare provided, the SPD must be on the load side of at least one overcurrent protective device. Where the industrialmachinery is located on the load-side of the branch-circuit overcurrent protective device, Type 1, Type 2 or Type 3SPDs shall be provided. Where Type 3 SPDs are provided and if included in the manufacturer’s instructions, the Type 3SPD connection shall be a minimum of 10 m (30 ft) of conductor distance from the service or separately derived systemdisconnect.

Revision correlates with the UL 1449, 3rd Edition changes to clarify the devices are now called “SurgeProtection Devices”. In addition, the revised text helps clarify the installation requirements for these devices, whether forprotection of lighting or switching surges. In either case, SPDs must be installed per product markings/instructions andconnected to protect all equipment requiring protection. Additionally, new text has been added to require a specificType of SPD that is suitable for the installation location of the industrial machinery and correlates with NEC Article 285.




Revise text to read:7.9 Power Factor Correction Capacitors.7.9.1 Overcurrent Capacitor Overcurrent Protection. Where capacitors are installed for motor power factor correction

on circuits of 600 volts, nominal, and under, overcurrent protection for the conductors shall be provided. Each capacitorcell or capacitor bank shall be protected against rupture of the individual cells. Protection included as a part of thecapacitor assembly shall be permitted.


_______________________________________________________________________________________________79- Log #95 EEI-AAA

_______________________________________________________________________________________________Barry Boggs, Toyota Motor Manufacturing North America

Revise text to read:8.1.2 Connections. Grounded conductors shall not be connected to the equipment grounding (protective bonding)

circuit, except for separately derived systems. Transformer or Direct Current Power Supply mounting hardware shall notbe used for either grounding or bonding terminations.

Including prohibition of grounding or bonding by using mounting hardware of DC Power Supplies addsfurther clarity to similar prohibition as applied to transformers.

_______________________________________________________________________________________________79- Log #111 EEI-AAA


Add a new section to read:8.2 Machine Members. Machine members or structural parts of the electrical equipment shall be permitted to be used

in the equipment grounding circuit provided that the cross-sectional area of these parts is at least electrically equivalentto the minimum cross-sectional area of the copper conductor required.

This information was removed from the 2007 and 2012 edition of NFPA 79 and should be re-inserted.No evidence of a problem was provided in the substantiation other than separating the equipment grounding conductorfrom the circuit conductors would increase its effectiveness. Many times the wiring methods are supported directly fromthe machine so separation is minimal. Machine designers can choose to provide equipment grounding conductors andequipment bonding conductors if desired.




Add new text to read: Bonding/Grounded systems shall have a resistance of 10 ohms or less to earth ground, including systems havingmultiple components or devices.Exception: Engineered electronic circuits that require separate ground plane path or surge current control to “earth

ground.”Guidance has not given as to what constitutes an effective conductive path to “earth ground.”

_______________________________________________________________________________________________79- Log #27 EEI-AAA


Add new text to read:All machines and/or auxiliary material handling attachments in an industrial cell, or sub-cell, shall be grounded, and

connected to the same derived power supply ground reference.Different machines and related auxiliary equipment being configured in a production cell, may be

powered from different derived power sources that supply the facility. Different voltage potential (potential and static)could have different ground voltage references that could cause equipment malfunction and hazard.Customer ran a ground wire from one line of equipment to an adjoining similar line and drew an arc – voltage potential

difference, “ground shock” hazard.

_______________________________________________________________________________________________79- Log #99 EEI-AAA

_______________________________________________________________________________________________Andras Szende, TUV Rheinland of North America, Inc.

Revise and add text to read:(2) Equipment grounding (protective) conductors including sliding contacts where they are part of the circuit and

equipment bonding jumpers(3) The exposed conductive parts and conductive structural parts of the electrical equipment(4) Those extraneous conductive parts which form the structure of the machine.

Sliding contacts may be the only way to bond certain moving parts of the machine, so this should bestated in the section (also part of IEC 60204-1). Conductive parts of the machine structure logically should be part of theprotective bonding circuit. If only conductords and terminals are allowed, a lot of material is wasted and the performanceof the bonding circuit may not be better by it. This is also addressed in IEC 60204-1. We receive numerous complaintsfrom customers regarding the wording and requirements of this chapter.




Add new text to read:Where wire conductors are used to connect movable auxiliary piece(s) of equipment to the common machine ground

bonding system, the minimum size of the bonding or grounding wire is dictated by mechanical strength, not by itscurrent carrying capacity.

Unpowered auxiliary equipment could be bonded to the ground circuit by the minimum size conductorspecified in Table 8.2.2.3, but the environment and anticipated movement of the auxiliary equipment to allow access tothe machine or process components would not be mechanically substantial to take the normal stress and abuse on aproduction floor environment. This would all the use of a conductor that would have greater ability to resist mechanicalfailure (i.e.: use of 1/0 welding cable for the bond conductor).

_______________________________________________________________________________________________79- Log #17 EEI-AAA


Revise to read: 8.3.1 4 Ungrounded control circuits shall be provided with an insulation-monitoring device that either indicates a

ground (earth) fault or interrupts the circuit automatically after a ground (earth) fault.The section as currently numbered does not comply with the NFPA Manual of Style which states that


_______________________________________________________________________________________________79- Log #98 EEI-AAA

_______________________________________________________________________________________________Andras Szende, TUV Rheinland of North America, Inc.

Add new text to read:9.1 Control Circuits. Control circuits performing safety functions shall comply with the risk assessment requirements

for the machine they control and the safety-related functions (or safety functions) they carry out on the machine.Evaluation of the safety functions performed by the circuit shall be made according to the applicable functional safetystandards to the degree identified by the risk assessment. Some examples of safety functions can be emergencystopping, interlocking, temperature or speed control etc.Triggering a safety function shall result in bringing the machine to a safe state, usually by stopping (category 0 or 1) or

removing power to an actuator. Resetting of the safety circuit shall not increase the risk or result a hazardous situation.In the original text it was not clearly stated how to use risk assessment and functional safety evaulation

in safety control circuit design. It was also not clear how and when a reset to a safety circuit could happen.




Revise text to read: 9.2.2 Stop Functions. Stop functions shall operate by de-energizing that relevant circuit and shall functions shall

override related start functions. The reset of the stop functions shall not initiate any hazardous conditions. The threecategories of stop functions shall be as follows:

The current text requires that stop functions operatre by de-energization. This is likely possible in stopcategories 0 and 1 but not necessarily in stop function 2. The text is overly prescriptive and needs to be modified. Thereare other ways to modify the ext to address this issue but I'll leave that to the Committee. The fact is that we alreadyhave in H2(3) the implied recommendation to stop by de-energization.

_______________________________________________________________________________________________79- Log #6 EEI-AAA

_______________________________________________________________________________________________Roger Zieg, Zieg Electric

Revise to read:9.2.2 Stop Functions. Stop functions shall operate by de-energizing that relevant circuit or by removing power to the

machine and shall override related start functions. The reset of the stop functions shall not initiate any hazardousconditions. The three categories of stop functions shall be as follows:(1) Category 0 - Type 1 is an uncontrolled stop by immediately removing power to the machine actuators.Category 0 - Type 2 will initiate an emergency switching off (e.g. shunt trip of the main disconnect).(2) Category 1 is a controlled stop with power to the machine actuators available to achieve the stop then remove

power when the stop is achieved.(3) Category 2 is a controlled stop with power left available to the machine actuators.

There is confusion on the difference between a Category 0 stop and an Emergency Switching Off. Bydefinition they are different with the Emergency Switching Off removing power to the machine and the Category 0 Stopremoving power to the actuators. I believe that by identifying both as a Category 0 but with a type associated with it,clears up the confusion.

_______________________________________________________________________________________________79- Log #88 EEI-AAA


Revise text to read: 9.2.5.3.1 Each machine shall be equipped with a Category 0 stop. Where a Category 1 stop is provided by the

emergency stop function, the supply disconnecting means shall be permitted to fullfil the requirement for Category 0stop.9.2.5.3.2 Category 0, Category 1, and/or Category 2 stops shall be provided where provided as indicated by an

analysis of the risk assessment and the functional requirements of the machine. Category 0 and Category 1 stops shallbe operational regardless of operating modes, and Category 0 shall take priority.

Machines may require that the emergency stop function be a category 1 stop which can appear toconflict with the requirement to provide a Category 0 stop . The revised language clarifies that the supply disconnectingmeans provides the Category 0 stop in these cases.This proposal was developed as part of the NFPA 79 Technical Committee Chapter 9 Control and Technology Task

Group.



_______________________________________________________________________________________________David McCune, Leggett and Platt Idea Center

Revise to read: 9.2.5.3.2 Category 0, Category 1, and/or Category 2 stops shall be provided where indicated by an analysis of the risk

assessment and the functional requirements of the machine. Category 0 and Category 1 stops shall be operationalregardless of operating modes, and Category 0 shall take priority. Category 2 stops buttons shall be momentary notlatching or maintained.

All too often I see operators using a maintained category 2 stop under their direct control in place oflockout tag out, and while it is safe most of the time, there is still an increased risk by using a category 2 stop instead ofa category 0 or 1.

_______________________________________________________________________________________________79- Log #21 EEI-AAA


Revise to read: 9.2.5.4.2.1 Emergency switching off shall be permitted as follows under any of the following conditions:

The revised text clarifies that any or all of the conditions listed are acceptable for use of emergencyswitching off.

_______________________________________________________________________________________________79- Log #19 EEI-AAA


Revise to read:9.4.1* General Requirements. Where failures or disturbances in the electrical equipment cause a hazardous condition

or damage to the machine or the work in progress, measures shall be taken to minimize the probability of theoccurrence of such failures or disturbances. The electrical control circuits shall have an appropriate level of performancethat has been determined from the risk assessment of the machine.9.4.1.1* Risk Reduction Measures. Measures to reduce these risks shall include, but are not limited to, one or more of

the following:The section as currently numbered does not comply with the NFPA Manual of Style which states that

all subdivisions shall contain at least two subdivisions. This change is the result of the Editorial Task Group review of the2012 document for compliance with 1.8.1 of the NFPA Manual of Style.A title was added to identify the contents of the subsection and to be consistent with other 1st & 2nd level subdivisions

in 9.4.

_______________________________________________________________________________________________79- Log #72 EEI-AAA


Renumber 9.4.1.1 as 9.4.2.The section as currently numbered does not comply with the NFPA Manual of Style which states that





Delete the asterisk.Delete reference to improper annex note. The note pertains to design of control system using software

and firmware based controllers (9.4.3.4.2).This proposal was developed as part of the NFPA 79 Chapter 9 Control and Technology task group.

_______________________________________________________________________________________________79- Log #85 EEI-AAA


Revise text to read:9.4.3.4.2* Control systems incorporating software- and firmware-based controllers performing safety-related functions

shall be self-monitoring and conform to all of the following (1) In the event of any single failure, the failure shall:

(a) Not lead to the loss of the safety-related function(s)(b) Lead to the shutdown of the system in a safe state(c) Prevent subsequent operation until the component failure has been corrected(d) Prevent unintended startup of equipment upon correction of the failure

(2) Provide protection equivalent to that of control systems incorporating hardwired/hardware components(3) Be designed in conformance with an approved standard that provides requirements for such systems

Use of firmware and/or software based control is becoming more prevalent even in what was oncesimple safety relays. Proper design of these control systems should be based on the risk assessment of the machineand appropriate safety standards. The revised wording and associated annex note provides the needed guidance tomachine builders.This proposal was developed as part of the NFPA 79 Chapter 9 Control and Technology task group.

_______________________________________________________________________________________________79- Log #74 EEI-AAA


Revise text to read:10.3.1.12 Indicator Light Circuits for Warning or Danger. Indicator light circuits used for warning or danger lights shall

be fitted with facilities to check the operability of these lights.The section as currently numbered does not comply with the NFPA Manual of Style which states that

all subdivisions shall contain at least two subdivisions. This change is the result of the Editorial Task Group review of the2012 document for compliance with 1.8.1 of the NFPA Manual of Style. In addition, a title has been added to beconsistent with the other subdivisions under 10.3.




Revise text to read:(2) Where it is of the type described in 5.3.2(1), through 5.3.2(2), or 5.3.2(3)

All of the supply disconnecting means identified in 5.3.2(1) - 5.3.2 (5) can be equipped with suitableexternal operatings means to serve as an emergency stop. Only where it is a plug and cord should it not be permitted.This proposal was developed as part of the NFPA 79 Chapter 9 Control and Technology task group.

_______________________________________________________________________________________________79- Log #40 EEI-AAA


Add new text to read as follows:Exception: A screw with 32 threads per inch (32 threads per 25.4 mm) may be used on 0.053 inch (1.35 mm) thick

steel subplate.UL 50 defines this thread engagements as suitable to attach covers. UL 508A 66.1.9 defines this

thread engagement as suitable for mounting equipment to sub panels.

_______________________________________________________________________________________________79- Log #39 EEI-AAA


Revise text to read as follows:Enclosures of control equipment shall provide a the degree of protection required for the environment to be

used, for indoor locations where adverse ingress environments are not present a minimum degree of protection of atleast NEMA Type 1 is required.

11.3.1 or 11.3.2 does not provide the requirement that the enclosure rating must meet the operatingenvironment. 11.3.2 as written provides an minimum requirement of Type 1 with no environmental considerations.

_______________________________________________________________________________________________79- Log #38 EEI-AAA


Revise text to read as follows:Where corrosion protection beyond normal requirements is needed, nonmetallic enclosures identified for the purposes

shall be permitted if they meet the requirements of ANSI/ UL508 and UL50E.ANSI UL 50 and UL50E Enclosures for Electrical Equipment provide the base standard guidance for

evaluating the structural considerations and environment integrity for long term exposures of nonmetallic enclosures,specifically polymeric enclosures located in UL50 6.6 and UL50E 7.1.




Add new text to read as follows:Thermal heating effects within the enclosure. The maximum allowable temperature with the enclosure shall be

evaluated based on the lowest component temperature rating. To maintain internal temperatures below this temperaturethe addition if enclosure cooling equipment is allowed and is selected to maintain the degree if environmental protectionthe machine is intend to operate in.

This test is added to provide consideration for environmental conditions inside the enclosure andensure that the method of thermal management will maintain the enclosure rated integrity.

_______________________________________________________________________________________________79- Log #114 EEI-AAA


Add new last paragraph to read:Working space for enclosures that contain supply conductors that are covered by NEC Article 670 shall be provided in

accordance with the NEC.Article 670.1 Informational Note indicates that work space requirements of 110.26 apply to supply

circuit terminations. The NEC applies to the supply conductors.

_______________________________________________________________________________________________79- Log #5 EEI-AAA

_______________________________________________________________________________________________Mark Mathews, UT-Battelle, LLC

Revise text to read:The working space shall permit at least 90-degree opening of control cabinet and

compartment doors or hinged panels.

Section 11.5 requires “sufficient access and working space” be provided around all control cabinetsand compartments, and subsection 11.5.1 defines the sufficient working space. However, the sentence immediatelyfollowing the heading of subsection 11.5.1 implies (1) the entire subsection applies only to working spaces in front ofdoors and hinged panels, and (2) compartments with bolted or screwed-on covers are not subject to the minimumworking space requirements stated in Subsection 11.5.1 even if they are “likely to require examination, adjustment,servicing or maintenance while energized”. Moving the sentence immediately following the subsection 11.5.1 headinginto its own paragraph would clarify the scope and intent of the subsection.




Revise text to read:Exception No. 4: Condition 1 working clearance depth shall be permitted between control cabinets or compartments

located across the aisle from each other, or across from a grounded surface, and where all associated control cabinet orcompartment devices and equipment operating at greater than 50 volts rms ac or 60 volts dc are separately enclosed,guarded, or constructed so that openings to live parts of the devices and equipment will not permit the entry of a 12.5mm (0.5 in.) diameter rod.

By making this editorial change it will clarify the parameters of the specific conditions that exception #4applies to. The change makes the terminology consistent within the exceptions.

_______________________________________________________________________________________________79- Log #60 EEI-AAA

_______________________________________________________________________________________________Yuji Hamano, TUV Rheinland Japan

Revise text to read as follows:The width of the working space in front of control cabinets and compartments shall be the width of the control cabinet

or - compartment, 750762 mm (21/2 ft), whichever is greater.All description of '21/2 ft' calculate '762mm' except this Section 11.5.1.2.

_______________________________________________________________________________________________79- Log #93 EEI-AAA


Revise text to read:11.5.1.2 The width of the working space in front of control cabinets and compartments shall be the width of the

opening into the control cabinet or compartment, or 750 762 mm (2 1⁄2 ft 30 in.), whichever is greater.The accessible opening into control cabinets or compartments is typically less than the overall width of

the control cabinet or compartment because of flanges and non-removable portions of the cabinets and compartments.The existing requirement is over restrictive as it implies the working space width shall is based upon the overall width ofthe control cabinet or compartments and not the actual accesible opening. Additionally the minimum width requirementsof 750 mm (2-1/2 ft.) is not in alignment with the more precise SI value of 762 mm (30 in.) as stated in the requirementsof the NEC Article 110.26(A)(2).

_______________________________________________________________________________________________79- Log #96 EEI-AAA


Add a new section to read:11.5.1.4 The standing area, floor or platform, directly in front of the control cabinet or compartment and within the

required working space depth and width shall be realtively flat to prevent trips and falls while working on the electricalequipment.

The standard is not clear regarding the surface in front of the control cabinet or compartment. Uneverand slanted floor surfaces can create trip and fall hazards for individuals working on the exposed electrical equipment.



_______________________________________________________________________________________________Mark Lehrman, ABB

Revise text to read as follows:

******Insert Table 12.5.1 Here******

1. The current values for 75°C wire in Table 12.5.1 are equal to (or, in cases of the larger wire sizes,not more than 5% below) the ampacities of 90°C wire, derated to 40°C ambient. Per Clause 12.5.5, a 90°C wire used ina 40°C ambient would need to be derated a second time, this time according to the 75°C derating factors, which is notnecessary. At other ambients, again, 90°C wire is derated twice, and the resulting ampacity will be much less than the90°C derated ampacity. For instance, a 1 AWG, 90°C wire used in 50°C ambient should derate to 150 × 0.82 = 123 A,under 12.5.2, and Tables 12.5.1 and 12.5.5 it can carry only 130 × 0.75 = 97.5A.2. 60°C wire is permitted in NFPA 79, and ambient correction factors are more severe than for 75°C wire. These

should be included in Table 12.5.5(a).3. It should not be necessary to derate conductors covered by NEC 240.4(D) if the maximum current allowed by

240.4(D) is below the derated current allowed by NEC Table 310.16.

_______________________________________________________________________________________________79- Log #1b EEI-AAA

_______________________________________________________________________________________________Mark Lehrman, ABB

Revise text to read as follows:

******Insert Table 12.5.5(a) Here******

1. The current values for 75°C wire in Table 12.5.1 are equal to (or, in cases of the larger wire sizes,not more than 5% below) the ampacities of 90°C wire, derated to 40°C ambient. Per Clause 12.5.5, a 90°C wire used ina 40°C ambient would need to be derated a second time, this time according to the 75°C derating factors, which is notnecessary. At other ambients, again, 90°C wire is derated twice, and the resulting ampacity will be much less than the90°C derated ampacity. For instance, a 1 AWG, 90°C wire used in 50°C ambient should derate to 150 × 0.82 = 123 A,under 12.5.2, and Tables 12.5.1 and 12.5.5 it can carry only 130 × 0.75 = 97.5A.2. 60°C wire is permitted in NFPA 79, and ambient correction factors are more severe than for 75°C wire. These

should be included in Table 12.5.5(a).3. It should not be necessary to derate conductors covered by NEC 240.4(D) if the maximum current allowed by

240.4(D) is below the derated current allowed by NEC Table 310.16.


ROP / A2014 / NFPA 79/ Log # 1 / Table 12.5.1 /Rec

Table 12.5.1 Conductor Ampacity Based on Copper Conductors with 60°C and 75°C Insulation in an Ambient Temperature of 30°C1,2

Conductor Size (AWG) Ampacity

60°C 75°C 90oC 30 – 0.53 0.53

28 – 0.83 0.83

26 – 13 13

24 23 23 23

22 33 33 33

20 53 53 53

18 76 77 74

16 106 107 104

14 155 156 157

12 20 5 205 207

10 30 305 306

8 40 50 55 6 55 65 75 4 70 85 95 3 85 100 110 2 95 115 130 1 110 130 150 1/0 125 150 170 2/0 145 175 195 3/0 165 200 225 4/0 195 230 260 250 215 255 290 300 240 285 320 350 260 310 350 400 280 335 380 500 320 380 430 600 355 420 475 700 385 460 520 750 400 475 535 800 410 490 555 900 435 520 585 1000 455 545 615 Notes: (1) Wire types listed in Section 12.3.1 shall be permitted to be used at the ampacities listed in this table. (2) The sources for the ampacities in this table are Table 310.16 and Clause 240.4(D) of NFPA 70, National Electrical Code. (3) Control conductors only. Ampacity need not be derated. (4) Ampacity need not be derated for ambient temperature. (5) If ambient is less than 40oC, ampacity need not be derated. If ambient is greater than 40oC, derate according to Table 12.5.5(a), using ampacities from Table 310.16 of NFPA 70, National Electrical Code. (6) If ambient is less than 50oC, ampacity need not be derated. If ambient is greater than 50oC, derate according to Table 12.5.5(a), using ampacities from Table 310.16 of NFPA 70, National Electrical Code. (7) If ambient is less than 60oC, ampacity need not be derated. If ambient is greater than 60oC, derate according to Table 12.5.5(a), using ampacities from Table 310.16 of NFPA 70, National Electrical Code.

ROP / A2014 / NFPA 79/ Log # 1 / Table 12.5.5(a) /Rec

Table 12.5.5(a) Ambient Temperature Correction Factors For ambient temperatures other than 30°C (86°F) multiply the allowable ampacities shown by the appropriate factor shown below. Ambient Temperature (°C)

Correction Factor 60°C



21–25 1.08 1.05 1.04 26–30 1.00 1.00 1.00 31–35 0.91 0.94 0.96 36–40 0.82 0.88 0.91 41–45 0.71 0.82 0.87 46–50 0.58 0.75 0.82 51–55 0.41 0.67 0.76 56–60 — 0.58 0.71 61–70 — 0.33 0.58 71–80 — — 0.41


_______________________________________________________________________________________________Noel Williams, Noel Williams Consulting

Add correction factors for 90 degree C conductors. These for 21 degrees C (69 degrees F) orgreater should be copied directly from Table 310.15(B)(2)(a) in the 2011 NEC.

With the addition of 90 degree C conductor ampacities, the lack of corresponding correction factors isan apparent oversight. Termination temperatures will continue to be limited by the general reference to the NEC inSection 1.4. There is no technical reason why the correction factors for 75 degree conductors should be applied to 90degree conductors. There are many high temperature applications for conductors in industrial machines and the correctprovisions should be available for wiring on the machines just as it is for premises wiring.

_______________________________________________________________________________________________79- Log #91 EEI-AAA

_______________________________________________________________________________________________Roger Plemmons, Rockwell Automation

Revise text to read:(2) Motor power circuits with supplying a motor load having a full-load ampacity current rating of 8 amperes or less,

provided all the following conditions are met:(3) Motor power circuits with supplying a motor load having a full-load ampacity current rating of 5.5 amperes or less,

provided all the following are met:This change clarifies the meaning of “full-load ampacity” in 12.6.1.1 (2), 12.6.1.1(3), 12.6.1.2(2) and

12.6.1.2(3). The use of “full-load” with “ampacity” is unclear because full-load refers to motor ratings, while ampacityrefers to the current-carrying capacity of conductors (see 3.2.5.1 of 2011 NEC Style Manual). The proposed text usesthe full-load current rating of the motor load because the Substantiation for 13.6.1 in the 2002 ROP states “Guidelineswere selected for…maximum full load current rating of motors …The criteria for determining the maximum full loadcurrent rating was …(10 sec for class 10, etc.)…This then derived the FLC ...”

_______________________________________________________________________________________________79- Log #92 EEI-AAA

_______________________________________________________________________________________________Roger Plemmons, Rockwell Automation

Revise text to read:(2) Motor power circuits with a circuits supplying a motor load having a full-load ampacity current rating of 5 amperes or

less, provided all the following conditions are met:(3) Motor power circuits with supplying a motor load having a full-load ampacity current rating of 3.5 amperes or less,

provided all the following are met:This change clarifies the meaning of “full-load ampacity” in 12.6.1.1 (2), 12.6.1.1(3), 12.6.1.2(2) and

12.6.1.2(3). The use of “full-load” with “ampacity” is unclear because full-load refers to motor ratings, while ampacityrefers to the current-carrying capacity of conductors (see 3.2.5.1 of 2011 NEC Style Manual). The proposed text usesthe full-load current rating of the motor load because the Substantiation for 13.6.1 in the 2002 ROP states “Guidelineswere selected for…maximum full load current rating of motors …The criteria for determining the maximum full loadcurrent rating was …(10 sec for class 10, etc.)…This then derived the FLC ...”




Revise to read:12.9.2 Appliance wiring material (AWM) shall be permitted as follows under any of the following conditions:

The revised language clarifies the intent of the 2012 change that any of the conditions of 1,2, or 3 canbe applied to demonstrate acceptable use of AWM.

_______________________________________________________________________________________________79- Log #59 EEI-AAA

_______________________________________________________________________________________________Yuji Hamano, TUV Rheinland Japan

Revise text to read as follows:Appliance wiring material (AWM) shall be permitted as follows one of the followings:

It is not clear that 'all of the followings' or 'one of the followings' regarding the following (1), (2), (3)requirements.

_______________________________________________________________________________________________79- Log #67 EEI-AAA


Revise text to read: 12.9.2 Appliance Appliance wiring material (AWM) shall be permitted as follows to be installed in accordance with one

or more of the following:The current wording may be interpreted to require that more than one subdivision in the section shall

be complied with in order to install AWM.This editorial change will clarify that either (1), (2) or 3 are permitted means for installing AWM.



_______________________________________________________________________________________________Stefna Grunwald, Lutze Inc.

Add a new section to read:

THHN based wiring is not adequate to sustain the nonlinear power distortions caused by VFD's andamplified by long cable runs. The use of VFD’s in combination with long cable runs from the Drive to the motor amplifiesthe problems. This is specific to Drives with Pulse width modulation. Here are the two types of wiring that cause aconcern:TC-ER cable rated 600V with PVC Nylon insulation which is marketed as DRIVE or Power Tray cableTHHN 600V in

conduit.Both wiring methods cause the same problems:In both cases the insulation has proven to be inadequate for VFD applications and the cable can short out after pitting

caused by corona discharge degraded the conductor insulation over time and ultimately allowed a spark from conductorto conductor. This typically happens on the motor end, far away from the Drive. Even when the conductors were sizedcorrectly per NEC table 310.15 (B) this premature cable failure can occur with 600V rated thermoplastic wiring, inparticular THHN.

It is our opinion that the high capacitance for PVC/Nylon insulation and the thin thermoplastic wall is causing thesefailures and therefore presents a potential hazard. THHN wiring is rated for 600V but many Drives cause spikes wellabove the nominal Voltage and well beyond 600V.THE NEC table 310.15 (B) rates a THHN conductor 90°C for the same ampacity as a RHW-2 conductor. The insulation

wall thickness requirements for any PVC/Nylon conductor is much less than the requirement for a 1000V rated flexiblemotor supply cable with RHW-2 insulation.Any AWG12 conductor per UL 1063 construction B has a minimum wall thickness of 15 mills of PVC plus 4 mills of

Nylon rated for 600V. The same AWG12 conductor per RHW-2 has a 45 mil wall thickness for insulation and is rated1000V.Using tray cable with THHN conductors as VFD cable also creates ampacity problems due to the high charging

current. A 4c shielded cable with THHN insulation has a mutual capacitance of 95 pF/ft. The same cable with RHW-2insulation only has a capacitance of 22 pF/ft. The high charging current of the THHN insulated cable leads to a higherheat dissipation, therefore reducing the actual permissible ampacity even further.Due to the high charging current there is more ampacity on the cable than expected if the cable lead length is long.

Multiple runs of cables in tray amplify the heat dissipation further, reducing the ampacity for each cable.PVC/Nylon Insulation such as THHN is prone for Corona Discharge at high voltages and if used in moist environments.

The reflected wave phenomena known to occur in variable frequency Drives with pulse width modulation can cause thevoltage at the motor end to go well beyond 1000V and can cause Corona Discharge.The RHW-2 insulated cable would therefore have less charging current, dissipates less heat and can sustain much

higher voltage spikes without allowing arcing between conductors.Another problem is with retrofits. People retrofit devices with Drives with the idea of saving energy. However, often timesthe old THHN in conduit wiring that was already there is being reused to connect the motor to the Drive. This PVC mayhave had a significant aging process and should not be reused. UL has recently updated the category for Flexible MotorSupply cables under ZJFH and updated the language from flexible motor supply to "flexible VFD Servo cable 1000V". Ithink the NFPA 79 should reference this listing or at least should make a difference in permissible ampacity and leadlength between thermoplastic insulations (THHN) and thermoset insulation such as RHW-2 when used with Drives andPulse width modulation. Many Drive manufacturers such as Rockwell even include warnings in their Drive manuals notto use THHN insulated conductors whether they are in conduit or part of a multi conductor cable for the reasonsdescribed.




Revise text to read:13.1.4 Conductors Supplied from Separate Disconnects. Where the equipment is supplied from has two or more

sources of power or two from two or more independent disconnecting means, the power wiring from each supply sourceor from each disconnecting means shall be run in a separate raceway and shall not terminate in or pass throughcommon junction boxes.

The proposed changes will clarify the separation requirements of this section apply to the supplycircuits to the machine. This section has been mistakenly applied to circuits the originated on the load side of machinesupply disconnecting means which can occupy the raceway unless prohibited elsewhere in the Standard.In addition the Technical Committee may want to consider the location of this requirement. This language originated in

the JIC Standards and was related to applications where there were multiple supplies or multiple supply disconnectingmeans that were not interlocked with each other. The requirements were clearly related to the supply circuits. In thecurrent edition of NFPA 79, the interlocking requirements are covered in Chapter 6 and the supply disconnecting meansrequirements are located in Chapter 5.

_______________________________________________________________________________________________79- Log #75 EEI-AAA


Revise text to read:13.5.10.111 Cords in Cable Trays. Cords shall not be installed in cable trays.

The section as currently numbered does not comply with the NFPA Manual of Style which states thatall subdivisions shall contain at least two subdivisions. This change is the result of the Editorial Task Group review of the2012 document for compliance with 1.8.1 of the NFPA Manual of Style. In addition, a title has been added to beconsistent with the other 1st level subdivisions in 13.5.

_______________________________________________________________________________________________79- Log #76 EEI-AAA


Renumber 14.1.1 as 14.2.The section as currently numbered does not comply with the NFPA Manual of Style which states that


_______________________________________________________________________________________________79- Log #7 EEI-AAA

_______________________________________________________________________________________________Roger Zieg, Zieg Electric

Revise to read:Receptacles shall be of the parallel blade grounding type, 125-volt, single-phase, 15- or 20- ampere configuration and

listed for the applied voltage.The 20 ampere configuration of the single phase, 125 volt receptacle, required for this section is in

conflict with the requirement found in 7.2.5.2 where the overcurrent protection for the accessory receptacle shall notexceed 15 amperes. There is not a need for a 20 ampere receptacle for the accessory equipment that may be utilized atthis location. Generally this is for connection of things like a laptop computer to interface with the PLC, or aprogramming device of a VFD.




Revise text to read: Electrical equipment for industrial machines, such as industrial control panels and the enclosures of disconnecting

devices, shall be marked with a safety sign in accordance with ANSI Z535.4 to warn qualified persons of potentialelectric shock and arc flash hazards.

To assure that any warning sign for shock and arc flash hazards comply with the guidance for suchsigns as provided by ANSI Z525.4.

_______________________________________________________________________________________________79- Log #49 EEI-AAA


Revise text to read as follows:(6)* Short-circuit current rating of the industrial control panel

The revised wording correlates with NEC 670.3(4) and adds clarity to how to determine the SCCR ofmachine industrial control panel by adding new A.16.4.1(6) where more complex industrial machinery is utilized withmultiple industrial control panels/enclosures and disconnects.

_______________________________________________________________________________________________79- Log #48 EEI-AAA


Revise text to read as follows:19.1 Overload Overcurrent Protection for Servo Drives and Motors. OverloadBranch-Circuit overcurrent protection shall

be provided for each servo drive and motor in accordance with manufacturer’s markings and instructions. Theshort-circuit current rating of the servo drive and motor shall be included in the determination of the short-circuit currentrating of the machine industrial control panel.

The revised text indicates that branch-circuit overcurrent protection, not just overload protection isrequired for servo drives and motors. The manufacturer’s instructions for servo drives and motors indicate the type andsize of branch-circuit overcurrent protection that is required and the associated SCCR in accordance with UL 508C. Inaddition, UL 508A considers servo drives SCCR in the determination of the industrial control panel SCCR.



_______________________________________________________________________________________________Stefna Grunwald, Lutze Inc.

Add new sections to read:Cables. Cables supplying Variable frequency motor drive or servo motor drive systems and motors shall be

listed flexible motor supply cable or flexible VFD Servo cable with a minimum rating of 1000V, 90C.Individual conductors in raceways supplying Variable frequency motor drive or servo motor drive

systems and motors shall be thermoset insulation types RHH, RHW, RHW-2, XHHW or XHHW-2 with a minimum rating1000V, 90C.

Circuit conductors supplying servo drive systems shall be sized tohave an ampacity not less than 115 percent of the rated input of the equipment.

Motor circuit conductors shall have an ampacity of at least 115 percent of the motorfull-load current when operated in a continuous mode of operation or as specified by the servo drive systemmanufacturer.Motor circuit conductors for motors operating in other than continuous mode shall be permitted to have reduced

ampacity based upon the design load and duty cycle.Remainder of paragraphs to be renumbered

See additional Public Input Log #61 (Public Input No. 39).VFD applications utilizing Pulse width modulation create some unique electrical issues and THHN wiring cannot

address these electrical issues properly.

_______________________________________________________________________________________________79- Log #26 EEI-AAA


Revise to read:A.3.3.32 Duct. Conduits, cable trunking systems (see 3.3.1415), and underfloor channels are types of duct. See also

3.3.80, Raceway.Section 3.3.14 refers to Cable Tray Systems. The reference should be section 3.3.15 as it references

Cable Trunking Systems.This editorial change will clarify the documents reference.

_______________________________________________________________________________________________79- Log #110a EEI-AAA


Add a new section to read:A.3.3.51 * The terms "protective bonding", "bonding conductor" and "protective conductor" are used in place of the

term "equipment grounding conductor" in some other standards.This is a companion input to delete parenthetical terms in NFPA 79. Add the information in Annex A to

describe the terms sometimes used in place of the term equipment grounding conductor.




Renumber A.9.4.1.1 as A.9.4.2.This section is being renumbered as 9.4.1.1 was renumbered 9.4.2 to comply with the NFPA Manual

of Style which states that all subdivisions shall contain at least two subdivisions. This change is the result of the EditorialTask Group review of the 2012 document for compliance with 1.8.1 of the NFPA Manual of Style.

_______________________________________________________________________________________________79- Log #83 EEI-AAA


Renumber A.9.4.3.2 as A.9.4.4.2.The annex note incorrectly references 9.4.3.2. 9.4.3.4.2 which deals with software and firmware based

controllers.This proposal was developed as part of the NFPA 79 Chapter 9 Control and Technology task group.

_______________________________________________________________________________________________79- Log #3 EEI-AAA


Revise text as follows:For additional information related to motor standards, refer to UL 1004 ANSI/UL 1004-1, NEMA MG-1, IEEE

841, or IEC 60034-1.The protection requirements for motors and associated equipment are given in Section 7.2 for overcurrent protection,

in Section 7.3 for overload protection, and in Section 7.6 for overspeed protection.Delete reference to UL 1004 and add reference to ANSI/UL 1004-1 which replaces UL 1004.

_______________________________________________________________________________________________79- Log #50 EEI-AAA


Add new text to read as follows:A.16.4.1(6) The short-circuit current rating of the machine industrial control panel includes all power circuit

components located in the machine industrial control panel, the main machine disconnect, where not located within oradjacent to the machine industrial control panel, and power circuit components located in electrical enclosuresdownstream of the machine industrial control panel.

The revised wording correlates with NEC 670.3(4) and adds clarity to how to determine the SCCR ofmachine industrial control panel by adding new A.16.4.1(6) where more complex industrial machinery is utilized withmultiple industrial control panels/enclosures and disconnects.




B.1It is recommended that the information in Figure B.1 be provided by the intended user of the equipment. It facilitates anagreement between the user and supplier on basic conditions and additional user requirements to ensure proper design,application, and utilization of the electrical equipment of the machine (see Section 4.1).


_______________________________________________________________________________________________79- Log #97 EEI-AAA


Add new text to read:(4) Conveyors and conveying machines

Adding the terms Conveyors and conveying machines adds further clarity to types of equipmentmeeting the description "Material-Handling Machinery".

_______________________________________________________________________________________________79- Log #69 EEI-AAA


*waiting for proposed changes to figures from Submitter, (doc. uploaded in terra cannot be opened)email sent 7/18/12

In the 1997 edition and previous editions the figure does not include the term module. It appearsduring reprinting and updating this figure for electronic configurations (PLC’s) the term module was mistakenly added tothe voltage input.

_______________________________________________________________________________________________79- Log #78 EEI-AAA


D.1Figure D.1(a) through Figure D.1(q) are not intended to be (design) guidelines. They are included only to illustratedocumentation methods.





Annex D Figure D.1 (g) PLC Output Diagram Change “Input” to “Output” from the phrase “120 VACInput Module” and remove the term “module” from the phrase “120 VAC Input Module” from the top of the table betweenline indicators 401 and 402 and also between lines 423 and 424.

In the 1997 edition and previous editions the figure does not include the term module. It appearsduring reprinting and updating this figure for electronic configurations (PLC’s) the term module was mistakenly added tothe voltage input.

_______________________________________________________________________________________________79- Log #79 EEI-AAA


E.1 Device Device and Compound Designations.The section as currently numbered does not comply with the NFPA Manual of Style which states that


_______________________________________________________________________________________________79- Log #80 EEI-AAA


F.2.1 Type-rated and IP-rated electrical enclosures have only the following in common:(1) A degree of protection for persons from hazardous components inside the enclosure(2) A degree of protection for equipment inside the enclosure from ingress of solid foreign objects, including dust(3) A degree of protection for equipment inside the enclosure from ingress of water

The section as currently numbered does not comply with the NFPA Manual of Style which states thatall subdivisions shall contain at least two subdivisions. This change is the result of the Editorial Task Group review of the2012 document for compliance with 1.8.1 of the NFPA Manual of Style. In this case the section number was removed asopposed to renumbering in sequence. The information provided is related to the ratings of both "Type-rated" and"IP-rated" and therefore a second level subdivision is not necessary.




F.5.3.1Where more than one supplementary letter is used, the following alphabetic sequence applies:(1) IPXXA. Protected against access with the back of hand(2) IPXXB. Protected against access with finger(3) IPXXC. Protected against access with a tool(4) IPXXD. Protected against access with a wireThese letter designations (A, B, C, D) can be used referencing the protection of live parts while the enclosure is

accessed. There is not a comparable NEMA 250 type-rating to this application.The section as currently numbered does not comply with the NFPA Manual of Style which states that

all subdivisions shall contain at least two subdivisions. This change is the result of the Editorial Task Group review of the2012 document for compliance with 1.8.1 of the NFPA Manual of Style. In this case the section number was removed asopposed to renumbering in sequence. The information provided is directly related to the text above and therefore asecond level subdivision is not necessary.

_______________________________________________________________________________________________79- Log #36 EEI-AAA


Add new Table F.5.4Table F.5.4 Enclosure Type Selection(add Table 110.28 of NFPA 70 2011)

Annex F provides a IP table definition and a Type rating versus IP rating comparison, but it does notprovide a reference to the Type rating definition and what criteria would be used to select an Enclosure Type rating.

_______________________________________________________________________________________________79- Log #82 EEI-AAA


I.1 Table I.1 provides a comparison of the conductor cross-sectional areas of the American WireGauge (AWG) with square millimeters, square inches, and circular mils


_______________________________________________________________________________________________79- Log #35 EEI-AAA


Add a new reference to read:NFPA 77, Recommended Practice on Static Electricity, 2007 edition.

To continue the practice all ready established in listing referenced material.



_______________________________________________________________________________________________J. B. Titus, JB Titus & Associates

Revise text to read:ANSI B11-TR3, Risk Assessment and Risk Reduction — A Guide to Estimate, Evaluate and Reduce Risks Associated

with Machine Tools, 2000..0, Safety of Machinery - General Requirements and Risk Assessment, 2010ANSI B11.TR3, Risk Assessmenrt and Risk Reduction, A Guide to Estimate, Evaluate and Reduce

Risks Associated with Machine Tools, 2000 has been rolled into ANSI B11.0, Safety of Machinery - GeneralRequirements and Risk Assessment, 2010. ANSI B11.0, 2010 provides the needed guidance to machine builders,modifiers, and end users.

_______________________________________________________________________________________________79- Log #101 EEI-AAA


Delete the following text:ANSI Z535.4, Product Safety Signs and Labels, 2007.

ANSI Z535.4, Product Safety Signs and Labels, 2007 is already listed as required in 2.3.1 and shouldnot be duplicated in Annex J.

_______________________________________________________________________________________________79- Log #100 EEI-AAA


Revise text to read:ISO 12100, Safety of machinery — Basic concepts, general principles for design — Part 1: Basic terminology,

methodology, 2003 2010.ISO 13849-1, Safety of machinery — Safety-related parts of control systems — Part 1: General principles for design,

1990 2006.ISO 13849-1 and ISO 12100 have been updated and are the current international standards in use

today. The revised dates will provide current needed guidance regarding functional safety, safety circuit designrequirements and the related risk assessments to machine builders, modifiers, and end users.




Revise text as follows:Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096.

ANSI/UL 50, , 2007.ANSI/UL 62, , 2006 2010.ANSI/UL 248-14, , 2000, Revised 2005 2010.ANSI/UL 489,

2009.ANSI/UL 498, , 2001, Revised 2009.ANSI/UL 508, , 1999, Revised 2010.UL 508A, , 2001, Revised 2010.ANSI/UL 651, , 2005, Revised 2008.ANSI/UL 758, , 2006, Revised 2009.UL 1004, , 1994, Revised 2006.ANSI/UL 1004-1, , 2008, Revised 2011.ANSI/UL 1077, , 2005, Revised 2009 2010.ANSI/UL 1682, 2007.ANSI/UL 60950-1, — , 2007, Revised 2011.UL Subject 2237,

, 2006 2011.IEC/UL 61010A-1, , 2002.

Delete reference to UL 1004 which has been replaced by ANSI/UL 1004-1 and add reference toANSI/UL 1004-1. Update other referenced standards to most recent edition as indicated.
