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NFPA 70E & Trane
Jim King Trane Carolinas District Safety Leader
(What Trane does and what you may need to do)
What is NFPA 70E® ?
Electrical Safety Triangle
1 Fatality
10 Recordable Injuries
10 to 1
Safety Triangle
1 Fatality
30 Lost Time Injuries
300 Recordable Injuries
30,000 Near Misses
300,000 At-Risk-Behaviors
300 to 1
A National consensus standard and a “Standard for Electrical Safety in the Workplace”
Is part of the National Electrical Code and has been adopted by OSHA as an
enforcement standard.
NFPA 70E was originally developed at OSHA’s request in 1976 to assist OSHA in
preparing electrical safety standards.
2
Why do anything?
OSHA- Between 1973 to 1993, 78% of elec equip related injuries were caused by Arc exposure. Injuries mainly burns & blindness
3
Annually
U.S. averages 4,000 non-disabling electrical contact injuries
Annually
U.S. averages 3,600 disabling electrical contact injuries
Every day 1 person is electrocuted in the workplace
Electrocutions are 4th leading cause of traumatic occupational deaths
Each year +2,000 workers are sent to burn centers with electrical burns
Safety First
Arc Flash Characteristics
1. Electric arcs produce some of the highest temperatures
known to occur on earth – up to 35,000 degrees
Fahrenheit. This is four times the surface temperature of
the sun
2. All known materials are vaporized at this temperature.
When materials vaporize they expand in volume (Copper
– 67,000 times, Water–1670 times). The air blast can
spread molten metal to great distances with force.
3. Rapidly expanding gases, extreme pressure and sound
waves, molten metal and metal plasma.
4. “Explosion in a Box”
4
NFPA 70E - Standard for Electrical Safety
Requirements for Employee Workplaces
• First published in 1979. 2009 edition was adopted in 2008.
• 2012 edition is the current edition
• Arc flash hazard was first addressed in the 2000 edition.
• 2015 edition to be released this fall.
• NFPA 70E sets concise rules on PPE requirements and safe
distances.
• Table 130.2(C) list the approach boundaries to live (energized)
parts.
• NFPA 70E was originally developed at OSHA’s request in 1976
to assist OSHA in preparing electrical safety standards.
Safety First
Standards Interaction
OSHA 29 CFR 1910
SUBPART S
NFPA 70-E
National Electric Code
IEEE Std 1584-2002
NFPA-70
(Institute of Electrical & Electronics Engineers)
Things
What we install
People
How we behave
2012 edition was approved as an American National Standard on
August 31, 2011. Effective September 1, 2011
(Supersedes all previous editions)
6
Safety First
Evolution of Electrical Safety
From NFPA 70E Handbook, 2004 Edition, p17 (Explanatory Commentary)
“Fire, shock, and electrocution have been considered to be electrical hazards for many years. Since
the publication of NFPA 70E, 1995 edition, arc flash has been considered to be an electrical hazard.
The arc flash hazard currently is defined to consider only the thermal aspects of an arcing fault.
Other hazards include flying parts and pieces and the pressure wave that is generated in an arcing
fault. Other electrical hazards also might be associated with an arcing fault.”
Fire
Shock
Electrocution
+
Arc Flash
Brief History of Electrical Safety
"The Other Electrical Hazard: Electric Arc Blast Burns” 1980
Ralph Lee (former consultant from DuPont) - published in the IEEE
8
• 1888 “The War of Currents”
Brief History of Electrical Safety
NECA = National Electrical Contractors Association
IBEW = International Brotherhood of Electrical Workers
9
Arc Flash Causes
1. Dust and impurities
2. Corrosion
3. Condensation
4. Spark discharge – Accidental contact: dropping tools
5. Over voltage across narrow gaps
6. Failure of insulating materials
7. Improper work procedures
10
Creating an NFPA 70E® Compliant Program
• Develop Electrical Safety Program – Written electrical safety procedure
– Safe work practices
– Training requirements
– PPE requirements
• Conduct Shock and Flash Hazard Analyses on all electrical equipment to determine appropriate levels of protection
• Train and outfit all affected personnel
Where did we go from here ?
(What Trane did)
11
Start With a Hazard Risk Analysis
Hazard/Risk Analysis is a decision making process:
• Evaluate equipment and circuit information to determine the degree and
extent of hazards
• Determine “Shock Approach Boundaries”
• Determine “Flash Protection Boundary”
• Determine “Incident Energy Exposure”
• Determine appropriate Personal Protective Equipment (PPE)
Must perform Shock and Flash Hazard Analyses when working
“on or near” energized parts (within Limited Approach Boundary).
12
Shock Hazard Analysis
• Protects against Contact with energized equipment
• Use highest voltage level of exposure
• Boundary distance based solely on voltage
• Boundaries drawn from table in standard – no calcs necessary:
– Limited – a safe approach boundary. Only qualified employees and
escorted unqualified employees may cross
– Restricted – Only qualified employees may cross. When working within this boundary, must use special precautionary techniques and PPE
– Prohibited – Only qualified employees protected by insulating materials
13
Safety First
Approach Boundaries
Restricted
Approach
Boundary
Condition
Nominal System
Voltage Range,
Phase to Phase
Exposed
Movable
Conductor
Exposed Fixed
Circuit Part
Includes
Inadvertent
Movement
Adder
Prohibited
Approach
Boundary
1 0 to 50 Not Specified Not Specified Not Specified Not Specified
2 51 to 300 10 ft. 0 in. 3 ft. 6 in. Avoid Contact Avoid Contact
3 301 to 750 10 ft. 0 in. 3 ft. 6 in. 1 ft. 0 in. 0 ft. 1 in.
4 751 to 15kV 10 ft. 0 in. 5 ft. 0 in. 2 ft. 2 in. 0 ft. 7 in.
5 15.1kV to 36kV 10 ft. 0 in. 6 ft. 0 in. 2 ft. 7 in. 0 ft. 10 in.
Limited Approach Boundary
1. “Limited” Boundary - Must be Qualified Person
2. “Restricted” Boundary - Must wear Electrical PPE
3. “Prohibited” Boundary - Must wear PPE as if direct contact is being made.
Working with Control Panel door open – in Restricted Approach Boundary
Table 130.4(C)(a)
NFPA 70E® 2012
Page 24
Flash Hazard Analysis
• Designed to prevent injury from the heat generated in an arc event – not contact (Shock)
• A Flash Hazard Analysis Shall Determine:
– Flash Boundary
Approach boundary from exposed energized parts within which a person without proper PPE could receive beyond a 2nd degree burn.
– Incident heat energy of possible arc flash based on:
Available fault current
Fault clearing time
Distance from exposed equipment
Directional dissipation of energy (arc-in-the-box scenarios)
• PPE Requirements within the Flash Boundary
15
Arc Flash Boundaries (NOT S-H-O-C-K)
• To protect from thermal burn due to arc flash
• Electrical systems 600V or less:
– 4 feet, or the calculated distance based on established
algorithms
• Electrical systems over 600V:
– Boundary based on incident energy as calculated or as given
in default tables in Standard
Work within the Flash Boundary will require AR Clothing &
electrical PPE to protect the employee from arc flash injury
(Good rule of thumb is 10 feet)
(Think of others without AR & PPE)
Office workers Customers Plumbers
Teachers Visitors Students
2012: The default 4′ arc flash protection boundary of earlier 70E editions has been removed from 70E 2012. This
boundary is now specified in inches for each unique situation and comes from one of two task tables: Table
130.7(C)(15)(a) for AC and Table 130.7(C)(15)(b) for DC. These tables also list the fault current, clearing time, and working
distance of protective devices in the heading of each table section.
16
FLASH BOUNDARIES
Restricted Shock Boundary: Qualified Persons Only
Flash Protection Boundary (FPB)
Must wear appropriate clothing & PPE
FPB dependent on fault level and time duration.
Prohibited Shock Boundary: Qualified Persons Only. PPE as
if direct contact with live part
Eq
uip
me
nt
Limited Shock Boundary: Qualified or Unqualified Persons*
* Only if accompanied by Qualified Person
Limited Restricted Prohibited
“Sparky”
17
Flash Hazard Analysis
• Determines the Flash Protection Boundary
• Determines the required PPE
• 2 Methods available:
1. Can use Default Tables in the NFPA 70E Standard – Classifies work tasks in a specific Hazard Risk Category (HRC)
– Specifies required PPE as a function of HRC
2. Can calculate the incident energy to employees if a fault occurred; Can then specify the required PPE based on predicted hazard level.
We compared default tables to calculated values:
• Used conservative, but reasonably expected input parameters
• Used 2 different calculation models (took highest values)
• Found calculated values to be less than default tables
18
Flash Hazard Analysis Method # 1 Default Tables
Tasks Performed on Energized Equipment
Panel boards or other equipment rated > 240 V and up to 600 V
Hazard/Risk
Category
Rubber
Insulating
Gloves
Insulated and
Insulating Hand
Tools
Parameters:
Maximum of 25 kA short circuit current available; maximum of 0.03 sec (2 cycle) fault clearing
time; minimum 18 in. working distance
Potential arc flash boundary with exposed energized conductors or circuit parts using above
parameters: 30 in.
Perform infrared thermography and other non-contact inspections outside the restricted
approach boundary
1 N N
Circuit breaker (CB) or fused switch operation with covers on 0 N N
CB or fused switch operation with covers off 1 Y N
Work on energized electrical conductors and circuit parts, including voltage testing 2 Y Y
Remove/install CBs or fused switches 2 Y Y
Removal of bolted covers (to expose bare, energized electrical conductors and circuit parts) 1 N N
Opening hinged covers (to expose bare, energized electrical conductors and circuit parts) 0 N N
Work on energized electrical conductors and circuit parts of utilization equipment fed directly by
a branch circuit of the panelboard
2 Y Y
NFPA 70E® 2012 Edition (Page 33-38)
Table 130.7(C)(15)(a) Hazard/Risk Category Classifications and Use of Rubber Insulating Gloves and
Insulated and Insulating Hand Tools-Alternating Current Equipment (Formerly Table 130.7(C)(9)
19
Flash Hazard Analysis Method # 2 Calculation Method
Formula: EMB = 1038.7 DB
-1.4738 tA[0.0093F2-0.3453F+5.9675] cal/cm2
EMB = Incident Energy (cal/cm2)
DB = Distance, (in.) [for Distances > 18 inches]
tA = Arc Duration, (sec.)
F = Bolted-Fault Short Circuit Current [16KA to 50kA]
Incident Energy Calculation (Arc in a 20 in. cubic box, open on 1 side)
Ref: “Predicting Incident Energy to Better Manage the Electric Arc Hazard on 600 V Power
Distribution Systems”, Dougherty, RL; Neal, TE; Floyd II, HL. IEEE Paper, 1998.
From IEEE 1584 – Guide to Performing Arc Flash Hazard Calculations
20
Flash Hazard Analysis Calculation Method
Can also use computer models such as:
Duke Power Arc Calculator, and several
other commercially-available products
We used both the IEEE method and the Duke Power
Calculator – Followed the IEEE Method.
IEEE Method gave the most conservative results.
21
Safety First
Confused yet?
i cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I
was rdanieg. The phaonmneal pweor of the hmuan mnid,
aoccdrnig to a rscheearch at Cmabrigde Uinervtisy,
it dseno't mtaetr in waht oerdr the ltteres in a wrod are, the
olny iproamtnt tihng is taht the frsit and lsat ltteer be in the
rghit pclae. The rset can be a taotl mses and you can still
raed it whotuit a pboerlm. Tihs is bcuseae the huamn mnid
deos not raed ervey lteter by istlef, but the wrod as a wlohe.
Azanmig huh?
22
Safety First
Focus On Engineering and Admin Controls
CSO S&H -42, Trane’s Electrical Procedure, Section 5.1.6 (p-6)
23
OSHA 1910. 335 “Safeguards for personnel protection”
(a) (2) (ii)
“Protective shields, protective barriers, or insulating materials shall be used to protect each employee from shock, burns, or electrically related injuries while that employee is working near exposed energized parts which might be accidentally contacted or where dangerous electric heating or arcing might occur. When normally enclosed live parts are exposed for maintenance or repair, they shall be guarded to protect unqualified persons from contact with the live part.”
Safety First
1. Affects mostly equipment owners, but may affect service organizations if they have all necessary info to determine hazard class.
2. Mechanical systems OEMs only supply internal circuit protection. Customer determines equipment disconnecting means and has a unique electrical infrastructure.
3. Old Requirement – Label required if work is expected to be done in an energized state, or when verifying power off. A generic label stating an Arc Flash Hazard Analysis is required – meaning “Follow the Table Method”.
4. New Requirement – Each piece of equipment must have a label with the incident energy or required PPE ensemble required to do work. No more generic labels
5. Arc Flash Hazard Analysis must be reviewed every 5 yrs, or whenever a major modification occurs (no definition of major modification in Standard). Therefore, the Label Must Be Dated.
Labeling Equipment
(C) Equipment Labeling. Electrical equipment such as switchboards, panel boards, industrial control panels,
meter socket enclosures, and motor control centers that are in other than dwelling units, and are likely to
require examination, adjustment, servicing, or maintenance while energized, shall be field marked with a label
containing all the following information: Changed From 2009
•130.5(C): Revised to identify types of electrical equipment required to be labeled, and expanded and clarified
the information required to be included on the label. Added requirement to document the method used to
determine information on label. Exception added to cover existing equipment labels.
(1) At least one of the following:
a. Available incident energy and the corresponding working distance
b. Minimum arc rating of clothing
c. Required level of PPE
d. Highest Hazard/Risk Category (HRC) for the equipment
(2) Nominal system voltage
(3) Arc flash boundary
Exception: Labels applied prior to September 30, 2011, are acceptable if they contain the available
incident energy or required level of PPE.
The method of calculating and data to support the information for the label shall be documented.
2012 NFPA 70E® Labels
25
1. Trained and/or retrained every 3 years (NFPA 70E section 110.2 (D)(3))
2. 105.3: Revised 110.3 to clarify that employees are to be trained prior to
implementing safety related work practices.
3. 110.1 (C): Specifies that training on the release of victims from exposed
energized equipment is required for employees who are exposed to shock
hazards and those who are responsible for taking action in case of such
emergencies, as well as an added provision for certifying employees on using an
automated external defibrillator.
4. 110.2(D)(1)(c): Clarifies that on-the-job training associated with this requirement
is necessary for the employee to be considered a qualified person and to provide
clarity on the duties being performed.
5. 110.2(D)(2): Clarifies the necessary level of training for unqualified people on
electrical safety-related work practices.
6. 110.2(E): Requires that the “content of training” be included in the training
documentation. Maintained for duration of employment
27
2012 NFPA 70E® Changes for Training
Engineering and Admin Controls
1. Reduce Fault Current and Duration of Arc Flash
– Change type of fusing, where appropriate
Faster clearing times
Current-limiting fusing
– Manufacture equipment with IP20 (Touch-Safe) components in control panels
– Replace breakers with faster operating devices such as fuses
2. Reduce Exposure – Add barriers (installed or portable) eg 1kV plastic rolls
– Add distance with different tools; extended probes; etc..
– Install external measurement points
Use of PPE to Control the Hazard is the Last Resort
Trane and other OEMs
starting to do this
28
Current-Limiting Fuses
“(4) For equipment protected by upstream current limiting
fuses with arcing fault current in their current limiting
range (½ cycle fault clearing time or less), the hazard/risk
category required may be reduced by one number.”
[note (4) above taken from NFPA 70E 2012 page 37]
Fuses with a rejection feature to prohibit the
installation of non-current-limiting fuses
29
Safety First
Should we spend all this money on PPE?
30
Safety First
Electrical PPE Requirements
Electrical PPE (rubber gloves, hard hat / arc face shield, AR clothing) is required for troubleshooting, applying LOTO and testing dead. After that,
1. The line side terminal of the disconnecting device may still be energized.
2. According to this standard, if you are “exposed” to energized parts, electrical PPE is still required.
“Exposed” means being within the Limited Approach Boundary, which is 1 ft, for circuits 120 – 480 V.
3. You can eliminate “exposure” and remove the PPE if you can “Insulate” or “Isolate” yourself from the energized parts.
4. Insulate by placing an insulating material over the part.
5. Isolate by placing a rigid barrier over the part to prevent contact, or ensure your body and all conductive tools remain > 1 ft. away.
PPE requirements based on your distance from “Exposed
Energized Parts”, not the equipment you’re working on
Safety First
Hazard Risk Category 1 • Jeans no longer allowed
• 2004 Ed. Allowed12 oz denim instead of FR pants
• FR pants are now required
Hazard Risk category 2* • Face Shield with FR balaclava, or arc flash hood
• 2004 Ed. did not require the balaclava
All Hazard Risk Categories • Hearing protection required – ear canal inserts only
• When layering over non-FR natural fibers (eg, cotton), the outer layer by itself must meet the required level of protection
• Cannot use cotton as part of the ATPV or EBT calculations
PPE Requirements
PPE Selection From Calculations
For Most Testing and Troubleshooting Work
Synthetic fibers, such as polyester, nylon, acetate, rayon, either alone
or in blends are not permitted – they melt at low temperatures,
adhere to the skin and increase the extent of injury.
Outer layer must AR
Voltage Clothing Gloves Other PPE
Safety Glasses
Class E Hard Hat
Safety Glasses
Class E Hard Hat with 8 Cal.
ATPV Face Shield
Balaclava HRC 2
Ear Canal Inserts
> 600 volts STOP! You must receive specific training, be qualified, and equiped for > 600 volts.
50 - 120 Volts
FR long-sleeve shirt, FR
T-Shirt and FR pants or
HRC 2 Coveralls
Leather Gloves (Class 00 if
possiblility of contact)
121 - 600 Volts
FR long-sleeve shirt, FR
T-Shirt and FR pants or
HRC 2 Coveralls
Class 0 (rated to 1kV)
Insulated Rubber Gloves w/
Leather Protectors
33
About Insulated Tools (Screwdrivers)
Working it hot (Maintenance & Repair) Trane doesn’t perform “Hot Work”
34
-not required because we don’t perform “hot work”
(i.e. screw driver tip on an energized wire or terminal).
But as a precaution, anytime a live panel door is open...
-potential of dropping or slipping with an un-insulated tool...
therefore using insulated tools are an added precaution.
Good idea, but not required
Insulated screw drivers?
Safety First
Hazard Risk
Category 0 Hazard Risk
Category 1
Hazard Risk
Category 2
Hazard Risk
Category 3
Hazard Risk
Category 4
TRANE
HRC PPE
35
Voltage Testing
“When using the voltage meter to test voltage after de-energizing a circuit, the
employee will:
1. Test the meter on a known, live source
2. Test the conductor or circuit part for the presence of voltage
3. Test the meter again on the known, live source before beginning work on the conductor or
circuit part.”
36
Safety First
Multimeters
Today’s electrical measurement equipment is designed to meet the IEC (International Electrotechnical Commission) standards for transient overvoltages. The IEC standard specifies categories of overvoltage based on the distance from the power source and natural damping of transient energy that occurs in electric distribution systems. IEC overvoltage installation categories are defined by the location of the equipment to be tested. They are: Category I is the signal level for telecommunications and electronic equipment. Category II is the local level for fixed or non-fixed powered devices (i.e. lighting, appliances, portable equipment, etc.) Category III is the distribution level – fixed primary feeders or branch circuits. These circuits are usually separated from utility service by a minimum of one level of transformer isolation. Category IV is the primary supply level. This refers to overhead or underground utility service to an installation. Within each installation category there are voltage classifications which determine the maximum transient withstand capability of the instrument.
Installation Category Voltage Classification Maximum Transient Capability
CAT II 600 V 4000 V peak impulse transient
CAT II 1000 V 6000 V peak impulse transient
CAT III 600 V 6000 V peak impulse transient
CAT III 1000 V 8000 V peak impulse transient
CAT IV 600 V 8000 V peak impulse transient
CAT IV 1000 V 12000 V peak impulse transient
Installation Category Locations
To ensure the right protection is provided for the job, it is recommended that Category IV multimeters be used; however, the minimum acceptable multimeter rating is Category III. When purchasing Category III or Category IV multimeters; make sure that the test leads supplied by the manufacturer are also rated as Category III or Category IV. When making up your own test leads, make sure all the components, connectors, wire, and test probes are rated Category III or Category IV. Note: Pomona and Belden are just a couple of manufactures that provide Category III and IV test leads and/or test lead components. Manufacturers’ specification and rating sheets can be readily obtained from the internet. As a standard practice, all test leads should undergo a visual inspection prior to use.
MINIMUM METER REQUIREMENTS
Last known earthly
residence of automotive fuse used to
replace original fuse
Test leads survived intact
Handheld test tool safety
Misusing measurement tools
Common errors
• Connecting a meter to a voltage source with the
meter set up in inline amps
– Amps mode on meter is almost a short circuit
• Trying to measure ohms or continuity
on a live circuit
– Some older meters cannot handle
the full voltage on the ohms function
Probe tips burned off
250 V fuse
didn’t open in
time
Poor quality leads and probes led to
injury.
Handheld test tool safety
Three common errors that are avoidable
Common DMM safety hazards
• Measuring voltage while test
leads are in the current jacks =
short-circuit!
Protection: Fluke meters use
high energy fuses.
• Contact with ac or dc power
source while in ohms mode.
Protection:Use a meter with “Overload Protection.”
Functions are self-protected to the meter’s
rated voltage.
• Using meter above its rated voltage, i.e., on medium
voltage circuits.
Protection: Good karma
Technician Clothing Before NFPA 70E®
Synthetic fibers, such as polyester, nylon, acetate, rayon, either alone or in blends are not permitted – they melt at low
temperatures, adhere to the skin and increase the extent of injury.
43
Relationship with Contractors
“When contractors are hired to help perform work on customer equipment, the following
responsibilities and actions are required on behalf of Trane and the Contractors:
Host Employer Responsibilities
• Notify Contractor of electrical hazards associated with the work that might not be
recognized by the Contractor.
• Notify Contractor of information needed by the Contractor to properly assess the extent of
hazards.
Contractor Responsibilities
• Employees will be made aware of site-specific hazards communicated from host
employer.
• Employees will follow NFPA 70E rules and safety-related work rules required by the host
employer.
• Advise the host employer of unique or unanticipated hazards found.
• Advise host employer of corrections to rule violations”
• Document meeting
44
Safety First
High Voltage is a Bear!
(Discovered by a Sprint Technician)
Real
Life
Demonstration
45
Safety First
Comments or Questions?