Grounding & Bonding Requirements Flashcards

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

Answer: 8 AWG

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.

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

Answer: 250.104

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

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

Answer: At the source of the separately derived system

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

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

Answer: 25 ohms

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

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

Answer: PVC conduit buried 8 feet

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

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

Answer: Grounded conductor and equipment grounding conductor

Per NEC 250.28, the main bonding jumper connects the grounded (neutral) conductor to the equipment grounding conductor and enclosure at the service.

When installing a concrete-encased electrode, what is the minimum length of reinforcing steel required?

Answer: 20 feet

NEC 250.52(A)(3) requires at least 20 feet of one or more steel reinforcing bars of at least ½-inch diameter encased in concrete.