The Ins and Outs of Grounding

Test your knowledge of the National Electrical Code (NEC).

1. The NEC indicates which electrical systems are required to be grounded, which systems are permitted to be grounded, and which systems are not permitted to be grounded.

Correct Answer: True

2. The term ______ means connected to ground or to a conductive body that extends the ground connection.

Correct Answer: Grounded (grounding)

3. Grounded conductors ______ are permitted to be identified either in the same manner as that required for conductors 6 AWG and smaller or, at the time of installation, by a distinctive white or gray marking at the terminations.

Correct Answer: 4 AWG or larger

4. A 480-volt (V), three-phase, 3-wire, delta-connected system is always required to be grounded.

Correct Answer: False

5. Where 30V alternating current (AC) systems are installed outdoors as overhead conductors, they ______ be grounded.

Correct Answer: are required to

6. Which of the following conductors is not present when installing an ungrounded system?

Correct Answer: Grounded conductor

7. Where a system can be grounded so the maximum voltage to ground from any system ungrounded conductor does not exceed 240V, the system must be grounded.

Correct Answer: False

8. The phase-to-ground voltage of a high leg in a 240/120V, three-phase, 4-wire, delta-connected system is ______.

Correct Answer: 208V

9. Separately derived systems supplied by transformers having a primary voltage rating of less than 1,000V are not required to be grounded if all but which of the following conditions is met?

Correct Answer: Continuity of line power is required.

10. Where a transformer secondary is 30V AC and the primary is supplied by an ungrounded source, the secondary must be grounded.

Correct Answer: True