CME Grounding, Bonding & Overcurrent Protection

Question 1

What is the minimum size copper equipment grounding conductor (EGC) required for a circuit protected by a 100A overcurrent device per NEC Table 250.122?

Accepted Answer

8 AWG

Answer

6 AWG

Answer

4 AWG

Answer

2 AWG

Question 2

Per NEC Article 250, what is the primary purpose of bonding metal parts in an electrical system?

Accepted Answer

To establish electrical continuity and conductivity between metal parts

Answer

To increase the current-carrying capacity of conductors

Answer

To reduce voltage drop in branch circuits

Answer

To provide surge protection from lightning

Question 3

Which of the following is explicitly prohibited as a grounding electrode per NEC 250.52(B)?

Accepted Answer

Metal underground gas piping system

Answer

Concrete-encased electrode

Answer

Ground ring

Answer

Metal water pipe with 10+ feet in soil

Question 4

The main bonding jumper at a service connects which two components?

Accepted Answer

The grounded (neutral) conductor to the equipment grounding conductor at the main service

Answer

The hot conductor to the neutral conductor at the panel

Answer

The grounding electrode conductor to the service entrance conduit

Answer

The neutral bar to the grounding electrode only

Question 5

Per NEC Table 250.66, what is the minimum size copper grounding electrode conductor (GEC) for a service with 3/0 AWG copper service-entrance conductors?

Accepted Answer

4 AWG

Answer

2 AWG

Answer

1/0 AWG

Answer

2/0 AWG

Question 6

Per NEC 250.30, where must the system bonding jumper be installed for a separately derived system?

Accepted Answer

At the source of the separately derived system

Answer

At the first disconnecting means only

Answer

At both the source and at each distribution panel

Answer

At the main service disconnect of the building

Question 7

Per NEC 110.9, equipment used to interrupt fault current must have an interrupting rating that is:

Accepted Answer

At least equal to the maximum available fault current at its terminals

Answer

Rated for 10,000 AIC minimum regardless of system fault levels

Answer

Determined only by the utility company

Answer

Based solely on the conductor ampacity