Master Article 250 - Grounding and Bonding

Question 1

According to NEC 250.96, bonding of equipment grounding conductors must provide:

1. Surge protection devices
2. Electromagnetic interference reduction
3. Effective ground-fault current path
4. Equipment isolation

Correct Answer: Effective ground-fault current path

Why: NEC 250.96 requires bonding to provide an effective ground-fault current path for equipment grounding systems.

Question 2

Per NEC 250.97, what bonding requirement applies to service raceways containing service conductors?

1. Bonding not required
2. Bonding required at one end only
3. Bonding required at both ends
4. Bonding required only for metallic raceways

Correct Answer: Bonding required at both ends

Why: NEC 250.97 requires service raceways to be bonded at both ends to ensure electrical continuity.

Question 3

According to NEC 517.19(F), isolated ground receptacles in health care facilities must be identified with what color?

1. Orange face with orange triangle
2. Red face with white triangle
3. Green face with green triangle
4. White face with orange triangle

Correct Answer: Orange face with orange triangle

Why: NEC 517.19(F) requires isolated ground receptacles in health care facilities to have an orange face with an orange triangle for identification.

Question 4

Under NEC 250.32(B)(1), for separate buildings with one branch circuit, what grounding method is required?

1. Equipment grounding conductor run with circuit conductors
2. Separate grounding electrode system
3. Connection to building structure
4. No grounding required

Correct Answer: Equipment grounding conductor run with circuit conductors

Why: NEC 250.32(B)(1) requires an equipment grounding conductor to be run with the circuit conductors for separate buildings or structures.

Question 5

According to NEC 250.4(A)(1), what is the primary purpose of grounding electrical systems?

1. To provide a low-impedance path for fault current
2. To limit voltage to ground during normal operation
3. To facilitate overcurrent device operation
4. To reduce electromagnetic interference

Correct Answer: To limit voltage to ground during normal operation

Why: NEC 250.4(A)(1) states that grounding limits voltage to ground during normal operation and stabilizes voltage during ground faults.