ESC ESC Electrical Grounding & Bonding 2

Question 1

What is the main bonding jumper used for?

Accepted Answer

To connect the grounded conductor to the equipment grounding conductor at the service

Answer

The main bonding jumper connects the grounded (neutral) conductor to the equipment grounding conductor and to the service enclosure at the main service equipment.

Question 2

What minimum length must a ground rod be driven into the earth per NEC 250.52?

Accepted Answer

8 feet

Answer

NEC 250.52(A)(5) requires ground rods to be at least 8 feet in length and driven to their full depth.

Question 3

In a separately derived system such as a transformer, where must the system bonding jumper be installed?

Accepted Answer

At the source of the separately derived system

Answer

Per NEC 250.30, the system bonding jumper for a separately derived system must be installed at the source of that system.

Question 4

Per NEC Table 250.66, what is the minimum copper GEC size for a 200-amp service with 3/0 AWG service conductors?

Accepted Answer

4 AWG

Answer

NEC Table 250.66 requires a minimum 4 AWG copper grounding electrode conductor for service conductors sized at 3/0 AWG.

Question 5

Which metal piping system MUST be bonded to the electrical grounding system per NEC 250.104?

Accepted Answer

Metal gas piping

Answer

NEC 250.104(B) requires metal gas piping to be bonded to prevent hazardous voltage differences that could cause ignition sparks.

(ESC) Electrical Safety Certification Practice Test

(ESC) Electrical Safety Certification Practice Test

ESC ESC Electrical Grounding & Bonding 2