8/12/2019 Understanding Ground Fault and Leakage Current

1/2

8/12/2019 Understanding Ground Fault and Leakage Current

2/2

02 Copyright material from the 2009 January Issue of The Code Authority: Electrical Connectionsnewsletter.This material may not reflect changes that have occurred since its original publication.

conductors, and are designed to interruptthe circuit when leakage current occursbetween a conductor and the shield.

Additional information for Leakage-CurrentDetection and Interruption may be located

under the UL Product Category ELGN.EGFPD (Equipment Ground-FaultProtective Device) Intended forapplications such as xed electric deicingand snow melting equipment, as well asxed electric heating equipment forpipelines and vessels, in accordance with

Articles 426 and 427 in the NEC. Thisdevice operates to disconnect the electriccircuit from the source of supply when theground-fault current exceeds the ground-fault pick-up level marked on the device,typically 6 mA to 50 mA. Additional

information for Ground-Fault ProtectiveDevices may be located under the ULProduct Category FTTE.

The fol lowing types of devices are ULComponent Recognized, and not intendedfor general sale or use. They are intendedfor use as factory-assembled componentsof specic appliances where the suitabilityof the installation is determined by UL. Theyhave not been investigated for installation inthe eld, and may or may not satisfyrequirements in the NEC.

ALCI (Appliance Leakage CurrentInterrupter) A component device onelectrical appliances, ALCIs are similar toGFCIs, as they are designed to interrupt thecircuit when a ground fault current exceeds6 mA. An ALCI is not intended to replacethe use of a GFCI device, where GFCIprotection is required in accordance withthe NEC.

IDCI (Immersion Detection CircuitInterrupter) A component device thatinterrupts the supply circuit to an immersedappliance. When a conductive liquid entersthe appliance and contacts both a live part

and an internal sensor, the device trips whencurrent ow between the live part and thesensor exceeds the trip current value. Thetrip current may be any value below 6 mAsufcient to detect immersion of theconnected appliance. The function of anIDCI is not dependent on the presence of agrounded object. Listed products thatcontain IDCIs or ALCIs have been investi-gated for installation in applications inaccordance with Section 422.41 of the NEC.

Proven Benet of Leakage Currentand Ground Fault Protection

To help mitigate electrical shock hazards,UL has been at the forefront of detectorresearch, technology and standardsdevelopment. Statistics have shown thatdevices described in this article haveproven to be an effective means to improvesafety in residential occupancies and otherelectrical installations. Proper applicationand use of these protective devices iscritical to coordinating required protectionfor safe installations.

Understanding Ground Faultand Leakage Current Protection (continued)

NEC Edition Where GFCIProtection Was FirstRequired1968 Swimming pool underwaterlighting

1971 Outdoor receptacles and nearswimming pools

1975 Bathroom receptacles andconstruction sites

1978 Garage receptacles

1981 Spas or hot tubs

1984 Bathrooms of hotel or motelguest rooms

1987 Basements, receptacles nearkitchen sinks, and boathouses

1990 Unnished basements and

crawl spaces

1993 Wet bar sinks

1996 All kitchen countertop recep-tacles, unnished accessory buildings,rooftops

2005 Near laundry and utility roomsinks, outdoors in public spaces

2008 All sinks (other than dwellingunits), electric water drinking fountains

GFPE Circuit Breaker