CEA NEC Wiring and Protection 5

Question 1

What is the minimum size copper conductor permitted for a main bonding jumper in a service panel supplying a 200-ampere service per NEC Table 250.66?

Accepted Answer

4 AWG

Answer

Per NEC Table 250.66, a 200-ampere service with 3/0 AWG or 4/0 AWG service entrance conductors requires a minimum 4 AWG copper bonding jumper.

Question 2

Under NEC 501.15, sealing fittings in Class I, Division 1 conduit systems must be installed within how many inches of an enclosure?

Accepted Answer

18 inches

Answer

NEC 501.15(A)(1) requires sealing fittings to be installed within 18 inches of enclosures, switches, circuit breakers, or fuses in Class I, Division 1 locations.

Question 3

Which NEC section requires arc-fault circuit interrupter (AFCI) protection for bedroom circuits in dwelling units?

Accepted Answer

NEC 210.12

Answer

NEC 210.12 requires AFCI protection for branch circuits supplying outlets in dwelling unit bedrooms and other specified areas.

Question 4

Per NEC 240.21(C), tap conductors from a feeder that are no longer than 25 feet must have an ampacity of at least what percentage of the feeder ampacity?

Accepted Answer

1/3 of the feeder

Answer

NEC 240.21(C)(2) allows 25-foot tap conductors if they have an ampacity of at least 1/3 of the rating of the overcurrent device protecting the feeder.

Question 5

What is the required minimum working clearance in front of a 240-volt panelboard installed in a residential dwelling per NEC 110.26(A)(1)?

Accepted Answer

30 inches

Answer

NEC 110.26(A)(1) Condition 1 requires a minimum of 30 inches of working clearance in front of electrical equipment operating at 0–150 volts to ground.

(CEA) Certified Electrical Apprentice Practice Test

(CEA) Certified Electrical Apprentice Practice Test

CEA NEC Wiring and Protection 5