Wiring and Protection Flashcards

Unless specifically permitted elsewhere, NEC 240.4(D) limits overcurrent protection for 12 AWG copper conductors to what maximum?

Answer: 20 A

Under the small-conductor rule in 240.4(D), 12 AWG copper is limited to 20-ampere overcurrent protection.

What is the maximum overcurrent protection permitted for 10 AWG copper conductors under the small-conductor rule of NEC 240.4(D)?

Answer: 30 A

NEC 240.4(D) limits 10 AWG copper to 30 A, even though its table ampacity can be higher.

NEC 240.4(B) allows using the next higher standard overcurrent device rating when a conductor's ampacity doesn't match a standard rating, as long as the device rating does not exceed what value?

Answer: 800 A

The next-size-up rule applies only when the overcurrent device is rated 800 A or less.

A branch circuit supplies a 16-ampere continuous load with no noncontinuous load. Per NEC 210.20(A), what is the minimum overcurrent device rating?

Answer: 20 A

16 A × 125% = 20 A, so a 20-ampere device is the minimum.

The informational note to NEC 210.19 recommends sizing branch-circuit conductors to keep voltage drop no greater than what percentage at the farthest outlet?

Answer: 3%

The note recommends no more than 3% on the branch circuit and 5% total for feeder plus branch circuit.

Under NEC 210.12, AFCI protection is required for 120-volt, 15- and 20-ampere branch circuits supplying outlets in which dwelling location?

Answer: Bedrooms

Bedrooms, along with most other habitable areas, kitchens, and laundry areas, require AFCI protection under 210.12.

Per NEC Table 250.122, what is the minimum copper equipment grounding conductor size for a circuit protected by a 100-ampere overcurrent device?

Answer: 8 AWG

Table 250.122 requires 8 AWG copper for overcurrent devices rated up to 100 A.