Journeyman Electrician Exam (NEC)Wiring Methods and MaterialsEasy
A maintenance technician is replacing a flexible cord on a portable 277-volt industrial machine. The machine requires a grounding conductor. What color insulation is typically used for the grounding conductor in a flexible cord for this application, according to NEC?
- AWhite or Gray
- BGreen or Green with Yellow Stripe
- CBlack
- DRed
Show answer & explanationAnswer & explanation
Correct answer: B. Green or Green with Yellow Stripe
According to NEC 250.119(B), the equipment grounding conductor in a flexible cord must be identified by a continuous outer finish that is either green or green with one or more yellow stripes. This universal color coding ensures clear identification of the safety grounding path.
Why the other options are wrong
- A. Incorrect. White or gray are typically used for identified (neutral) conductors in AC systems.
- C. Incorrect. Black is typically used for ungrounded (hot) conductors.
- D. Incorrect. Red is typically used for ungrounded (hot) conductors in multi-wire branch circuits or 3-phase systems.
Flexible Cord Grounding Color
The standardized color identification for the equipment grounding conductor within a flexible cord, as required by the NEC.
- Ensures easy and consistent identification of the grounding path.
- Crucial for electrical safety and preventing miswiring.
- Applies to all flexible cords containing a grounding conductor.
Memory trick: Green Ground is Always Green.