Equipment Grounding Conductors: What Counts, How to Size Them (Table 250.122), and How to Connect Them

"Grounding and Bonding Conductors" is a named sub-topic in the Branch Circuits area of every Texas outline, and Table 250.122 is one of the five tables you should be able to find with your eyes closed. This lesson covers Article 250 Parts VI and VII — the load side of the grounding system.

1. What must be connected to an EGC — 250.110, 250.112, 250.114

Fixed equipment (250.110) — exposed non-current-carrying metal parts of fixed equipment likely to become energised get an EGC if any of these apply: within 8 ft vertically or 5 ft horizontally of ground or grounded metal and subject to contact; in a wet or damp location and not isolated; in electrical contact with metal; in a hazardous location; supplied by a wiring method that provides an EGC; or operating with any terminal over 150 V to ground. Exceptions: double-insulated listed equipment (distinctively marked); pole-mounted distribution apparatus more than 8 ft up; specially permitted insulated frames.

Regardless of voltage (250.112): switchgear/switchboard frames, motor frames (430.242), motor-controller enclosures, elevator/crane equipment, garages/theaters/studios, electric signs, luminaires (410 Part V), skid-mounted equipment, motor-operated water pumps including submersibles, and metal well casings with submersible pumps.

Cord-and-plug equipment (250.114): in hazardous locations; over 150 V to ground; and in residential occupancies — refrigerators, freezers, A/C, washers, dryers, dishwashers, ranges, disposers, IT equipment, sump pumps, aquarium equipment, motor-operated tools, hedge clippers/mowers/snow blowers, portable handlamps; plus in non-residential — anything used in damp/wet locations or by persons standing on the ground or in tanks/boilers. Exception: listed double-insulated tools/appliances (marked).