CME Grounding, Bonding & Overcurrent Protection 3

Question 1

Per NEC 250.119, equipment grounding conductors must be identified by which of the following?

Accepted Answer

Green insulation, green with yellow stripes, or bare conductor

Answer

White or gray insulation only

Answer

Any color except black, red, or blue

Answer

Orange insulation for systems above 250V

Question 2

Per NEC 250.53(A)(2), when is a supplemental grounding electrode required when a single rod, pipe, or plate electrode is used?

Accepted Answer

When the single electrode has a resistance to ground exceeding 25 ohms

Answer

Always, regardless of soil resistance

Answer

When the electrode is longer than 8 feet

Answer

When the service exceeds 200A

Question 3

Per NEC 250.64(B), a grounding electrode conductor of what size or smaller must be protected from physical damage by installation in a raceway or armor?

Accepted Answer

6 AWG or smaller

Answer

8 AWG or smaller

Answer

4 AWG or smaller

Answer

10 AWG or smaller

Question 4

Per NEC 250.70, connections of grounding electrode conductors to grounding electrodes must be made using:

Accepted Answer

Listed lugs, listed pressure connectors, listed clamps, or other listed means approved for the purpose

Answer

Any UL-listed wire connector rated for the conductor size

Answer

Wire nuts rated for outdoor use

Answer

Mechanical set-screw connectors only

Question 5

Per NEC 240.4(D)(3), what is the maximum overcurrent protection permitted for a 10 AWG copper branch-circuit conductor?

Accepted Answer

30A

Answer

20A

Answer

25A

Answer

35A

Question 6

Which grounding electrode has the highest priority in the grounding electrode system hierarchy per NEC 250.50?

Accepted Answer

Metal underground water pipe with 10+ feet in contact with soil

Answer

Ground rod driven 8 feet into earth

Answer

Concrete-encased electrode

Answer

Plate electrode

Question 7

When a grounding electrode conductor is run inside a ferrous metal raceway, what bonding requirement applies per NEC 250.64(E)?

Accepted Answer

The raceway must be bonded to the GEC at both ends to prevent inductive choke effect

Answer

The raceway must be bonded at one end only to prevent circulating currents

Answer

The raceway must be removed and replaced with non-metallic conduit

Answer

No special bonding is required for GEC raceways