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August 2014
PARTNER IN GROUND FAULT PROTECTIONI-GARD CORPORATIONI-Gard Corporation
the best technology
Potential ground faults often go unnoticed and can cause havoc on plant production processes.
Shutting down power and equipment, ground faults disrupt the flow of products through
manufacturing processes, leading to hours or even days of lost productivity.
Undetected ground faults can also pose potential health and safety risks to personnel. Ground
faults can lead to safety hazards such as equipment malfunctions, fire and electric shock.
Ground faults can cause serious damage to equipment and to your processes. During a fault
condition, equipment can be damaged and processes shut down, seriously affecting your
bottom line.
I-Gard is acknowledged as the leader in the field of ground fault protection. I-Gard’s long-
standing relationships with a variety of Original Equipment Manufacturers (OEM) including ABB,
Eaton Yale, General Electric, Group Schneider and Siemens, attest to our exceptional level of
quality and performance.
The concern for ground fault protection is based on four factors:
The majority of electrical faults include ground.
The ground fault protective sensitivity can be relatively independent
of continuous load current values and thereby have lower pickup
settings than phase protective devices.
Since ground fault currents are not transferred through system
power transformers… the ground fault protection for each system
voltage level is independent… This permits faster relaying that can
be afforded by phase protective devices.
Arcing ground faults that are not properly detected and cleared
can be extremely destructive.
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proactive protection
the best technology
product portfolio
Working to improve the future of power protection, I-Gard invests
extensive resources on research and product development, with
the goal of proactively eliminating ground and arcing faults. Recent
innovations such as improved fault finding capabilities and enhanced
relay functionality have been developed with this goal in mind.
With extensive experience in ground fault protection, detection
and location systems, I-Gard understands how ground faults can
seriously affect equipment and processes. An extensive line of
ground fault application solutions assist in taking the appropriate
actions to ensure electrical systems are safe and properly
protected.
Capable of supplying a full product range, I-Gard ensures that every
customer’s unique combination of budget constraints and protection
requirements can be accommodated. Solutions range in scope from
fully engineered turnkey systems to replacement components for
existing installations.
Helping to improve industrial safety standards, I-Gard is actively
involved with all relevant standards agencies. Certification as an
independent test facility ensures the highest level of safety without
compromising delivery performance.
I-Gard has been committed to quality and is currently the only resistor
company in North America registered to ISO 9001:2008 since 1994.
This acknowledges the high level of in-house design capabilities in
addition to manufacturing expertise and customer focus. All I-Gard
products are CSA certified and UL recognized and listed.
setting the standard
solution capability
Over the last 30 years, I-Gard Corporation, formerly known as IPC Resistors Inc., has grown from a resistor
only company to one that fully incorporates our ground fault protection line into the company. We work to
achieve our business objectives responsibly and respond to our customer’s needs and concerns.
From research and development to the manufacturing and distribution of our products, safety and quality
are our first considerations. We are committed to manufacturing quality products and demand equivalent
standards from our suppliers to help ensure customer safety.
Quality Systems: I-Gard’s policies, guidelines, core requirements and procedures, are
designed to ensure consistent product quality worldwide. We are constantly evaluating our systems
in order to maintain the highest product quality.
Education and Training: I-Gard provides ongoing education and training programs on quality and
safety for all our employees.
Supplier Standards: We maintain strict quality standards and expect quality standards from our
suppliers as well.
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technology overview
Reported in Power Magazine, July 1969, that the cost of arcing ground faults ranged
between $1 billion and $3 billion annually for equipment loss, production downtime
and personal liability.
While a lot has changed in 30 years, losses due to ground faults remain a significant
issue today for the industry with one leading insurance company reporting that its
clients alone reported 228 losses that were attributed to ground faults with a total cost
of US $180 million over a seven year period.
Perhaps of greater concern are the five to 10 arc flash explosions that occur in
electrical equipment everyday resulting in medical treatment. According to statistics
compiled by CapSchell Inc. a Chicago-based research and consulting firm that
specializes in preventing workplace injuries and deaths.
The Bureau of Labor Statistics of the US Department of Labor compiles the Census
of Occupational Injuries from death certificates and other information for US workers
killed on the job. The 2003-2007 database shows that 1,213 workers died and 13,150
workers sustained days away from work due to occupational injuries and illnesses
involving contact with electricity.
I-Gard has developed methods for effectively minimizing the dangers of arc flashes
through the use of high resistance grounding. At the 2003 IEEE IAS Electrical Safety
Workshop it was stated that “high-resistance grounding for low voltage power
distribution systems enhances reliability and uptime of power distribution
equipment and is proven effective in significantly reducing the frequency and
severity of arc flash accidents”. Furthermore, the NFPA 70A recognizes High
resistance grounding as a mean to reduce Arc-Flash Hazards. According to a recent
study by John Nelson (IEEE), high resistance grounding eliminates the hazard of arc
flashes in 95% of all cases.
An arc flash is a short circuit through the air that takes place when the insulation between electrified conductors
is breached or can’t withstand the applied voltage. During an arc flash, an enormous amount of energy explodes
out from the electrical equipment, sometimes causing death or severe radiation burns to employees working near
energized conductors or circuits. The blast from the arc creates pressure waves that can damage hearing or brain
function and a flash that can damage eyesight.
WHAT IS AN ARC FLASH?
The common cause of the losses and injuries are undetected arcing faults that occur within a facilities
electrical distribution system. When an electrical system is grounded, there is an intentional connection of
a phase or neutral conductor to earth for the purpose of controlling the voltage to earth, or ground, within
predictable limits. It also provides for a flow of current that will allow detection of an unwanted connection
between system conductors and ground (a ground fault). The root cause of this unwanted connection is often
a result of insulation breakdown.
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QA
WHAT DOES IEEE SAY ABOUT UNGROUNDED SYSTEMS?
WHY CONSIDER GROUNDING YOUR SYSTEM?
Ungrounded systems offer no advantage over high-resistance grounded systems in terms of continuity of
service, and have the disadvantages of transient overvoltages, locating the first fault and burn-downs from a
second ground fault. For these reasons, they are being used less frequently today than high-resistance grounded
systems, and existing ungrounded systems are often converted to high-resistance grounded systems by
resistance grounding the neutral.
Once the system is high-resistance grounded, overvoltages are reduced and modern highly sensitive ground-fault
protective equipment can identify the faulted feeder on first fault and trip one or both feeders on the second fault
before an arcing burn-down causes serious damage.
- IEEE Standard 242-1986
The intentional connection of the neutral points of transformers, generators and rotating machinery to
the earth ground network provides a reference point of zero volts. This protective measure offers many
advantages over an ungrounded system, including:
Reduced magnitude of transient over-voltages
Simplified ground fault location
Improved system and equipment fault protection
Reduced maintenance time and expense
Greater safety for personnel
Improved lightning protection
Reduction in frequency of faults
WHAT IS A SOLIDLY GROUNDED SYSTEM?
A solidly grounded system is one in which the neutral points have been intentionally connected to earth ground with
a conductor having no intentional impedance. This partially reduces the problem of transient over-voltages found on
the ungrounded system, provided the ground fault current is in the range of 25% to 100% of the system three-phase
fault current. However, if the reactance of the generator or transformer is too great, the problem of transient over-
voltages will not be solved.
The majority of industrial facilities that experience arcing ground faults should not continue to operate without
adequate Ground Fault Protection. These establishments typically operate an ungrounded or solidly grounded
electrical distribution system, both of which have inherent disadvantages.
The reasoning behind the prevalence of ungrounded systems in many industrial facilities appears to be
historical. Prior to the emergence of High Resistance Grounding in the late 1980’s, the only choice when
process continuity was required was an ungrounded system that allowed for the controlled shutdown for fault
repairs at a convenient time, and this was of tremendous value to continuous manufacturing processes by
reducing production losses, equipment damage and outages.
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IS SOLIDLY GROUNDED SAFER THAN UNGROUNDED?
WHAT IS A RESISTANCE GROUNDED SYSTEM?
While solidly grounded systems are an improvement over ungrounded systems and facilitate the location of
faults, they lack the current limiting ability of resistance grounding and the extra protection this provides.
The destructive nature of arcing ground faults in solidly grounded systems is well known and extensively
documented. Electric arcs are caused by the energy dissipated in the fault. A measure of this energy can be
obtained from the estimate of kilowatt-cycles dissipated in the arc:
Kilowatt cycles = V x I x Time/1000
There are two broad categories of resistance grounding; low-resistance and high-resistance. In both types of
grounding, the resistor is connected between the neutral of the transformer secondary (or the neutral of the
electrical system) and the earth (ground).
HOW DO I DETERMINE WHAT SIZE OF NEUTRAL GROUNDING RESISTOR IS REQUIRED?
The resistor must be sized to ensure that the ground fault current limit is greater than the system's total
capacitance-to-ground charging current. If not, then transient over-voltages can occur. For more information consult
I-Gard at [email protected]
WHAT IS LOW-RESISTANCE GROUNDING?Low-resistance grounding of the neutral limits the ground fault current to a high level (typically 50 amps or more)
in order to operate protective fault clearing relays and current transformers. These devices are then able to quickly
clear the fault, usually within a few seconds. The importance of this fast response time is that it:
• Limits damage to equipment, prevents additional faults from occurring, provides safety for personnel and
localizes the fault
• The limited fault current and fast response time prevents overheating and mechanical stress on conductors.
However, like the solidly grounded neutral system, the circuit must be shut down after the first ground fault
• Low-resistance grounding resistors are typically rated 400 amps for 10 seconds, and are commonly found on
medium and high voltage systems
WHAT DOES IEEE SAY ABOUT SOLIDLY GROUNDED SYSTEMS?“ The solidly grounded system has the highest probability of escalating into a phase-to-phase or three-phase arcing
fault, particularly for the 480 and 600V systems. A safety hazard exists for solidly grounded systems from the
severe flash, arc burning and blast hazard from any phase-to-ground fault."
- IEEE Standard 141-1993
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WHAT IS HIGH-RESISTANCE GROUNDING?High-resistance grounding of the neutral limits the ground fault current to a very low level (typically under 25
amps). It is used on medium and low voltage systems where continuity of operations is important. Most industrial
distribution systems and critical facilities with distribution systems in medium and low voltage are ideal candidates
for high-resistance grounding.
WHY CONSIDER RESISTANCE GROUNDING?Resistance grounding is by far the most effective and preferred method. It solves the problem of transient over-
voltages, thereby reducing equipment damage. It accomplishes this by allowing the magnitude of the fault current
to be predetermined by a simple ohms law calculation. The fault current can be limited, in order to prevent
equipment damage.
Limiting fault currents to predetermined maximum values permits the designer to selectively coordinate the
operation of protective devices, which minimizes system disruption and allows for quick location of the fault.
WHAT DOES IEEE SAY ABOUT HIGH-RESISTANCE GROUNDED SYSTEMS? High-resistance grounding helps insure a ground-fault current of known magnitude, helpful for relaying purposes.
This makes it possible to identify the faulted feeder with sensitive ground-fault relays.
- IEEE Std 242-1986 7.2.4
High-resistance grounding provides the same advantages as ungrounded systems yet limits the steady state
and severe transient over-voltages associated with ungrounded systems. There is no arc flash hazard, as there
is with a solidly grounded system, since the fault current is limited to approximately 5A.
- IEEE Std 141-1993 7.2.2
WHY LIMIT THE CURRENT THROUGH RESISTANCE GROUNDING?
Throughout the 15 to 20 years high-resistance grounding has become the standard in hazardous applications
such as mining and petro-chemical, but until recently was limited in its application to industrial operations.
Only recently has high-resistance grounding been adopted as the method of choice by consultants designing
commercial facilities in North America (e.g. banks, data centres, hospitals, defence), and commercial facilities
outnumber industrial facilities by at least a factor of twenty.
• To reduce burning/melting effects in faulted electric equipment, such as switchgear,
transformers, cables and rotating machines.
• To reduce mechanical stresses in circuits and apparatus carrying fault currents
• To reduce electric-shock hazards to personnel caused by stray ground fault currents in the
ground return path
• To reduce arc blast or arc-flash hazard to personnel who may have accidentally caused or
who happen to be in close proximity to the fault current
• To reduce the momentary line-voltage dip caused by the occurrence and clearing of a
ground fault
• To secure control of transient over voltages while at the same time avoiding the shutdown
of a faulty circuit on the occurrence of the first ground fault
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Condition or Characteristic Ungrounded Solid Grounded Low-Resistance High-Resistance
Immunity to trransient Worst Good Good Best
Ground fault protection can be added
Worst Good Better Best
Equipment protected against arc fault
Worst Poor Better Best
Safety to Personnel Worst Better Good Best
Service Reliability Worst Good Better Best
Maintenance Costs Worst Good Better Best
Continued Production: After 1st Ground Fault
Better Poor Poor Best
Ease of Locating 1st Ground Fault Worst Good Better Best
Relay Co-ordination N/A Good Better Best
73% Increase in Voltage Stress Under Line-to-Ground Fault Conditions
Poor Best Good Poor
Two Voltage Levels On The Same Electrical System
N/A Best N/A N/A
Reduction in Frequency of Faults Worst Better Good Best
1st High Ground Fault Current Flows Over Grounding Circuit
Worst Better Good Best
Potential Flashover To Ground Poor Worst Good Best
METHOD OF GROUNDING
Comparative Performance Rating For Various Conditions Using Different Grounding Methods
unparalleled protection
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The I-Gard VIA has been designed specifically for ground fault
pre-alarm and alarm indication on high-resistance grounded or
ungrounded power systems. Additionally, the VIA can detect DC
ground faults that may occur on AC fed systems.
One or more optional flush mounted external displays (VIA–R)
can be mounted on panel doors or other locations. The isolation
inside the VIA protects the external displays from high voltages.
The VIA relay works on the principle of a change in line-to-
ground voltage that occurs when a fault appears on one of the
lines of the ungrounded or high-resistance grounded system.
product portfolio
While high-resistance grounding is the safest approach
to grounding a power system, some applications may
remain ungrounded (for legacy reasons) or solidly
grounded – the need to provide a reference to ground
or to supply single phase to neutral loads. At I-Gard we
have the necessary products to cover all applications.
UNGROUNDED DISTRIBUTION PROTECTION
When the desire to convert to a safer high-resistance grounded system
is delayed due to capital and time, a unique solution from I-Gard is
the Turbo Sleuth: a portable high-resistance grounding system that
temporarily and easily connects to an existing electrical system and
converts the faulted system to high-resistance grounded.
The Turbo Sleuth contains the fault-limiting resistor, the pulsing circuitry
and if requested, an artificial neutral in a single wheeled enclosure can
be added.
It uses an integral pulsing circuit to facilitate fault finding while ensuring
process continuity. Once the fault is located and cleared, the Turbo
Sleuth is disconnected and the system is returned to its original setting.
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Today’s protection requirements demand tripping at the
speed of light: The new Sentri includes three light sensor
inputs, that provide the Sentri with the ability to trip solid
state relays at the speed of light to protect personnel and
equipment from arc flash hazards, by tripping faster than
any other commercial relay.
To provide a total solution and coordination with other
devices, Sentri relay, range in trip levels from 10mA up
to 1200A, in a single format. This versatile relay can
be used in solidly grounded and resistance grounded
systems. Too often, systems are protected with just one
relay on the main service breaker, which leads to power
interruption of the entire service if a ground fault occurs
in any location. Consequently, in an effort to minimize
disruptions, the protection on the main breaker is often
set to maximum pickup and delay settings, or worse,
disconnected entirely. This can lead to substantial
equipment damage, due to increased clearing time.
Minimizing damage, downtime and maintaining
service, the Sentri relays with integral Zone Selective
Instantaneous Protection to protect systems, at LV
and MV system levels, with optimized coordination.
Maximum protection with minimum service disruption.
SOLIDLY GROUNDED PROTECTION
I-Gard offers a complete range of Neutral Grounding
Resistors (NGR) from 277V to 115 kV that are used for
resistance grounding of industrial power systems and are
usually connected between earth ground and the neutral
of power transformers, power generators or artificial
neutral transformers.
NGR's limit the maximum fault current to a value
which will not damage generating, distribution or other
associated equipment in the power system, yet allow
sufficient flow of fault current to operate protective relays
to clear the fault.
Along with our CSA category certification for NGR
products, all our NGR's are built to IEEE Standard
32, featuring line-to-line rated standoffs that provide
triple insulation to ground. I-Gard has standardized on
edgewound element design for NGR’s to deliver superior
and more consistent performance.
LOW-RESISTANCE GROUNDING PROTECTION
sentri light sensors
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DSP Second Fault Protection – unnecessary outages of electrical power
in continuous process industries or in critical systems applications such
as hospitals and air traffic control towers, cannot be tolerated and this has
increased the usage of high resistance grounding systems.
The new DSP-OHMNI is designed to provide an alarm, but not trip when one
ground fault occurs in the system- thus retaining system continuity.
If a second phase to ground fault develops on the system, before an existing
fault has been cleared, then the potential for serious damage results.
The DSP is the only relay to offer second fault protection through the SIFT
system (Selective Instantaneous Feeder Trip). Enabling the user to prioritize the
feeders and upon the occurrence of a second fault on a different phase, select
which feeder will instantaneously trip. Fault finding is made even easier with
the new optional pulsing module. The new generation DSP now offers resistor
monitoring through the DRM module and ModBus communication to facilitate
remote communication and management. The new digital display makes the
alarm and metering information more useful and easier to read.
HIGH RESISTANCE GROUNDING PROTECTION
DSP-OHMNI SYSTEM
Sleuth Gemini Sentinel Gardian
NGR Enclosed X X X X
GF Alarm X X X X
GF Pulsing X X X X
Resistor Monitoring X X X
Dual Path Resistor X X
Feeder Indication X X
2nd Fault Protection X X
Arc Flash Mitigation X
LISTED FEATURES OF I-GARD HRG PRODUCTS
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The m-GARD is a microprocessor based ground fault relay designed and built
to be used on solidly or resistance grounded systems. This innovative digital
electronic relay measures ground fault current using built-in Zero Sequence
Current Sensor (ZSCS), with the ability to operate on any control voltage supply,
it reacts to alternating current only and will reject direct current signals. With the
harmonic filtering feature enabled, the m-GARD provides the reliability required by
modern power systems with variable frequency drives.
The m-GARD-SYM remote indicator provides detailed device status information,
remote test/reset and Modbus connectivity for up to 50 I-Gard relays with an
isolated connection to an external Modbus RTU network. All 50 devices can be
monitored remotely using a single configurable Modbus address.
m-GARD RELAY
safety through innovation
With significant expenditure dedicated annually to
product development and application research, I-Gard
leads the way in bringing innovative new products to
market with a commitment to reducing electrical hazards.
The SuperGrid product enables the user to dissipate up
to 6 times the wattage of an industry standard grid and
is ideal for heavy applications where space is a premium.
A standard NEMA grid bank dissipates approximately
2kW of power where the patented SuperGrid typically
dissipates around 12kW per bank.
When Bombardier needed a heavy duty resistor for
their test track in Thunder Bay they decided on the
patented SuperGrid.
SUPERGRID
Patent 5,917,404
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In our continuing effort to bring new and innovative products to the electrical industry
that provide additional safety and performance benefits to the user, I-Gard has
developed a state-of-the-art protection relay for mobile trailing equipment, that
protects operators from electrical shock.
The level of safety provided is enchanced through the addition of AC touch voltage
protection, the only relay in the market with this feature.
GROUND CHECK MONITOR
SIGMA RELAYA combination of an NGR monitor and ground fault relay. It provides
adjustable pickup level and adjustable definite time delay for the
ground current. In resistance grounded systems, the NGR is constantly
monitored to ensure that the 3-phase 3-wire distribution system remains
fault free. SIGMA is designed for use on any resistance grounded system
that requires continuous monitoring of the NGR. A separately mounted
sensor measures the ground current and the voltage across the NGR.
The values measured are compared with settings and trip and alarms
are indicated when an abnormal condition is detected.
focus on quality
In addition to ISO standards for manufacturing quality, there are a number of
product specific guidelines and application standards from CSA, UL and IEEE
covering power resistors and ground fault protection products including: UL-508,
CSA 22.2 No. 14 for NGR's below 1.5 kV, for those above 5 kV UL-347 and the CSA-
22.2 TIL-D-31.
High-resistance grounding systems comply with UL-891 in addition to CSA 22.2
No. 14. Our relays are listed under UL-1053, CSA 22.2 no. 144 and those used for
people protection under UL-943. Mining Relays comply with M421-00.
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Our focus on quality and testing is exemplified by our CSA approved test facility
that permits I-Gard to develop and verify prototype resistors and relays and is
reinforced through our product category certifications.
All of our resistors elements and protective relays are both CSA certified and UL
recognized and listed.
commitment to standardsCSA International
Institute of Electrical & Electronics Engineers
National Fire Protection Association
Underwriters Laboratories inc.
C22.1 No. 02 2002 Canadian Electrical Code Part 1.
C22.2 No. 14-95 1995 (2001) Industrial Control Equipment
T.I.L. No. D-21 1995 Industrial Control Equipment No. 2
C22.2 No. 144-M91 1991 (1997) Ground Fault Circuit Interrupters
M421-00 2001 Use of Electricity in Mines
UL508 1999 Industrial Control Equipment
UL347 1993 High-Voltage Industrial Control Equipment
UL508C 1996 Power Conversion Equipment
UL50 1995 Enclosures for Electrical Equipment
UL943 2005 Ground Fault Circuit Interrupters
NFPA 70E 2005 National Electrical Code
IEEE Std 32 1972 Neutral Grounding Devices
IEEE Std 141 1999 Recommended Practice for Electric Power Distribution for Industrial Plants
IEEE Std 142 1991 Recommended Practice for Grounding of Industrial and Commercial Power Systems
IEEE Std 241 1997 Recommended Practice for Electric Power Systems in Commercial Buildings
IEEE Std 242 1991Recommended Practice for Protection and Coordination of Industrial and Commercial Power Systems
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unparalleled protection
Our reputation as the industry expert in Ground Fault Protection is hard earned and continually supported.
Whether we are providing Contracting Tips to Electrical Business to improve the contractor’s understanding
of High-Resistance Grounding and how to upgrade an ungrounded facility or partnering with EC&M on their
“Ask the Expert” program as their expert in Ground Fault Protection or delivering educational seminars at IEEE
conferences, our team of experts provides a depth and breadth of application knowledge that is unmatched in
the industry.
recognized as experts
Over the years I-Gard had partnered with Electrical Construction and Maintenance in
a campaign to address questions their readers would have on ground fault protection.
Today, our applications experts continue to raise awareness on the safety and
importance on high-resistance ground and ground fault protection directly from our
website www.i-gard.com. Submitting a question and addressing the issue has never
been easier. I-Gard is here to help in providing ground fault protection solutions that
suit and surpass your expectations.
“ASK THE EXPERT”
In conjuntion with industry leading trade magazine such as EC&M, Electrical Business, Electricity Today,
International Association of Electrical Inspectors e.t.c., I-Gard has furthered the understanding of the hazard
of arcing faults as well as the benefits and applications of high-resistance grounding through a number of
educational editorials.
INDUSTRY EDITORIALS
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application guides
Ground Fault Protection on Ungrounded & High-Resistance Grounded Systems
Application Guide
Ground Fault Protection High-Resistance Grounding
Consultant Specification Guide
Ground Fault Protection Ungrounded Systems to High-Resistance Grounding
Conversion Guide
Neutral Grounding Resistors Technical Information
Application Guide
Ground Fault Protection for Solidly Grounded Systems
Application Guide
Our Application and Specification guides, relied on by consultants, end-users and contractors, are constantly being
updated with the latest innovations. The following guides below are available for download from the I-Gard website
www.i-gard.com. Select the Technical Library link and then select Application Guides.
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application guides our production facility
I-Gard Electronic Assembly Area, where the entire
range of ground fault products are manufactured
and tested and where new product development is
undertaken in dedicated work cells.
With our focus on quality and flexibility, along with a manufacturing operation that has embraced lean manufacturing
principles; we provide industry leading service and quality levels. Our experienced, well trained and empowered
workforce process every order with the care and attention expected to ensure it is manufactured and shipped on time,
and to the highest quality level.
how to get in touch
I-Gard offers more HRG products at more price points than any other competitor in the industry, with customizable solutions for your specific application.
I-Gard is the exclusive supplier of FAIL-SAFE and SMART HRG systems with 2nd ground fault protection to better match your need for electrical reliability and safety.
We are the only HRG supplier that also offers optical arc mitigation for Total Protection against ground faults and arc flash incidences.
3 SOLUTIONS & FACTS ABOUT I-GARD
Corporate Office7686 Bath RoadMississauga, OntarioCanada L4T 1L2
Phone: 905-673-1553Fax: 905-673-8472Toll Free: [email protected]
