E2 Grounding and Bonding 3

Question 1

Under NEC 250.104, metal water piping systems in a commercial building must be bonded to which of the following?

Accepted Answer

Service equipment enclosure, grounded conductor, or grounding electrode conductor

Answer

NEC 250.104(A) requires metal water piping systems to be bonded to the service equipment enclosure, grounded conductor, or grounding electrode conductor.

Question 2

What is the minimum burial depth for a ground rod electrode per NEC 250.53(G)?

Accepted Answer

8 feet

Answer

NEC 250.53(G) requires ground rods to be driven to a depth of at least 8 feet to ensure adequate earth contact.

Question 3

Which type of grounding electrode is considered a 'made electrode' under NEC 250.52(B)?

Accepted Answer

Ground rod

Answer

Ground rods (and ground plates/rings) are classified as 'made electrodes' under NEC 250.52(B) because they are installed specifically for grounding.

Question 4

When is a main bonding jumper required in service equipment?

Accepted Answer

At every service disconnect enclosure

Answer

NEC 250.28 requires a main bonding jumper at each service disconnecting means to bond the grounded conductor to the equipment grounding conductor and enclosure.

Question 5

Concrete-encased electrodes (Ufer grounds) must contain at least how many feet of rebar or wire?

Accepted Answer

20 feet

Answer

NEC 250.52(A)(3) requires at least 20 feet of one or more steel reinforcing bars or bare copper conductors encased in concrete.

(E2) E2 Commercial Electrical Inspector Practice Test

(E2) E2 Commercial Electrical Inspector Practice Test

E2 Grounding and Bonding 3