PC Grounding and Bonding 5

Question 1

Structural steel of a building may be used as a grounding electrode if it is connected to at least how many ground rods, concrete-encased electrodes, or ground rings?

Accepted Answer

Two

Answer

NEC 250.52(A)(2) permits building steel as a grounding electrode when it is connected to at least two ground rods, concrete-encased electrodes, or ground rings.

Question 2

When installing a ground rod in rocky soil where the required 8-foot depth cannot be achieved vertically, what is the alternative permitted by NEC 250.53(G)?

Accepted Answer

Drive the rod at a 45-degree angle or bury it horizontally at 30 inches depth

Answer

NEC 250.53(G) allows rods that cannot be driven vertically to be installed at up to a 45-degree angle or buried horizontally at a minimum 30-inch depth.

Question 3

What NEC section governs the bonding of metal gas piping systems in a building?

Accepted Answer

NEC 250.104(B)

Answer

NEC 250.104(B) requires metal gas piping to be bonded to the electrical service equipment, the grounded conductor, or the grounding electrode conductor.

Question 4

In a health care facility, which grounding system is required in patient care areas to minimize leakage current?

Accepted Answer

Patient equipment grounding point (PEGP) with redundant EGC paths

Answer

NFPA 99 and NEC 517 require patient equipment grounding points providing redundant low-impedance EGC paths to protect patients from microshock hazards.

Question 5

Which statement correctly describes the difference between grounding and bonding?

Accepted Answer

Grounding connects equipment to earth; bonding connects conductive parts to each other to equalize potential

Answer

Grounding establishes a reference to earth potential, while bonding ensures electrical continuity between conductive parts to eliminate potential differences between them.

(PC) Professional Electrical Contractor Practice Test

(PC) Professional Electrical Contractor Practice Test

PC Grounding and Bonding 5