Licensed Electrical Contractor FREE Licensed Electrical Contractor Grounding and Bonding Questions and Answers 3

Question 1

What is the minimum burial depth required for a ground rod driven vertically into the earth per NEC 250.53?

Accepted Answer

8 feet

Answer

6 feet

Answer

10 feet

Answer

12 feet

Question 2

When using rigid metal conduit as an equipment grounding conductor, which of the following fittings is NOT acceptable for bonding at service equipment?

Accepted Answer

Standard locknuts

Answer

Bonding-type locknuts

Answer

Grounding bushings with bonding jumpers

Answer

Threaded hubs

Question 3

What is the maximum length of a bonding jumper for an interior metal water piping system before it must be sized per NEC Table 250.66?

Accepted Answer

There is no length limit; it is always sized per Table 250.66

Answer

5 feet

Answer

10 feet

Answer

20 feet

Question 4

A concrete-encased electrode (Ufer ground) must contain at least how many feet of reinforcing steel or bare copper conductor encased in concrete?

Accepted Answer

20 feet

Answer

10 feet

Answer

15 feet

Answer

25 feet

Question 5

When separately derived systems supply a building, what determines the sizing of the system bonding jumper?

Accepted Answer

The size of the largest derived ungrounded conductor

Answer

The rating of the overcurrent device protecting the system

Answer

The length of the raceway to the first overcurrent device

Answer

The total connected load of the system

Question 6

Bonding of communications systems grounding electrodes to the building power grounding electrode system is required by which NEC article?

Accepted Answer

Article 800

Answer

Article 230

Answer

Article 250

Answer

Article 810