CEI Grounding & Bonding Requirements 2

Question 1

What is the minimum size copper equipment grounding conductor required for a 60-ampere circuit per NEC Table 250.122?

Accepted Answer

8 AWG

Answer

NEC Table 250.122 requires a minimum 10 AWG copper EGC for circuits up to 60A, but 8 AWG is required when the overcurrent device rating is 60A.

Question 2

Which NEC section governs bonding of metal water piping systems in a building?

Accepted Answer

250.104

Answer

NEC 250.104 specifically covers bonding requirements for piping systems and exposed structural steel.

Question 3

A separately derived system's grounding electrode conductor must be connected at which point?

Accepted Answer

At the source of the separately derived system

Answer

Per NEC 250.30, the grounding electrode conductor for a separately derived system must be connected at the source (e.g., transformer secondary).

Question 4

What is the maximum resistance permitted for a made electrode (ground rod) before an additional electrode must be installed?

Accepted Answer

25 ohms

Answer

NEC 250.56 requires an additional electrode if a single rod, pipe, or plate electrode has a resistance to ground exceeding 25 ohms.

Question 5

Which of the following is NOT an acceptable grounding electrode per NEC 250.52?

Accepted Answer

PVC conduit buried 8 feet

Answer

PVC conduit is non-conductive and cannot serve as a grounding electrode; NEC 250.52 lists only metal or conductive materials.

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