EETC Grounding Systems 4

Question 1

What is the minimum length of a ground rod electrode required by the NEC?

Accepted Answer

8 feet

Answer

NEC 250.52(A)(5) requires ground rod electrodes to be at least 8 feet in length and must be installed to make contact with the soil.

Question 2

An equipment grounding conductor run in a conduit with ungrounded conductors must be sized based on which NEC table?

Accepted Answer

Table 250.122

Answer

NEC Table 250.122 is used to size equipment grounding conductors based on the ampere rating of the overcurrent device protecting the circuit.

Question 3

What is 'touch potential' in grounding system analysis?

Accepted Answer

The voltage between a grounded structure and a point on the earth's surface within arm's reach

Answer

Touch potential is the voltage difference between a grounded metallic structure and a point on the earth's surface that a person standing nearby could simultaneously contact.

Question 4

Which of the following is required when a grounding electrode conductor is run exposed along a wall?

Accepted Answer

It must be protected from physical damage where subject to it

Answer

NEC 250.64(B) requires that a grounding electrode conductor exposed to physical damage be protected by conduit, armor, or other approved means.

Question 5

What does the term 'bonding' mean in the context of NEC grounding requirements?

Accepted Answer

Permanently joining metallic parts to form an electrically conductive path

Answer

Bonding is the permanent joining of metallic parts to ensure electrical continuity and the ability to safely conduct any fault current.

(EETC) Electrical Technician Certification Practice Test

(EETC) Electrical Technician Certification Practice Test

EETC Grounding Systems 4