PC Grounding and Bonding 2

Question 1

According to NEC Article 250, what is the minimum size copper equipment grounding conductor required for a 100A circuit protected by a 100A breaker?

Accepted Answer

#8 AWG

Answer

NEC Table 250.122 requires a minimum #8 AWG copper EGC for circuits with overcurrent protection rated at 100A.

Question 2

Which of the following locations requires a grounding electrode system to include a ground ring if no other electrode is available?

Accepted Answer

Buildings or structures where no other electrode type exists on-site

Answer

NEC 250.52(A)(4) allows a ground ring as a grounding electrode when other electrode types are unavailable at the structure.

Question 3

What is the primary purpose of bonding in an electrical system?

Accepted Answer

To establish electrical continuity between conductive parts to eliminate voltage differences

Answer

Bonding ensures electrical continuity between conductive parts so no dangerous voltage differences exist between them.

Question 4

A concrete-encased electrode (Ufer ground) must contain at least how many feet of bare or zinc-galvanized steel reinforcing bars or rods?

Accepted Answer

20 feet

Answer

NEC 250.52(A)(3) requires at least 20 feet of steel reinforcing bar or rod encased in concrete for a Ufer ground.

Question 5

When installing a grounding electrode conductor in a metal raceway, what additional requirement applies?

Accepted Answer

The raceway must be bonded to the grounding electrode conductor at both ends

Answer

NEC 250.64(E) requires that when a GEC is installed in metal raceway, the raceway must be bonded to the GEC at both ends to prevent inductive choke.

(PC) Professional Electrical Contractor Practice Test