NABCEP Code Requirements 3

Question 1

Under NEC 690.47, which grounding method is acceptable for a transformerless (non-isolated) utility-interactive inverter PV system?

Accepted Answer

A grounding electrode system connected at the inverter with equipment grounding conductors throughout

Answer

NEC 690.47 requires a grounding electrode system and equipment grounding conductors throughout for transformerless inverter systems.

Question 2

NEC 690.15 requires a means to disconnect all ungrounded conductors of a PV system from all other conductors. What is this device commonly called?

Accepted Answer

PV system disconnecting means

Answer

NEC 690.15 mandates a PV system disconnecting means to isolate PV conductors from other wiring.

Question 3

Per NEC 705.12(B)(2), the sum of ampere ratings of overcurrent devices supplying power to a busbar or conductor shall not exceed what percentage of the busbar or conductor ampere rating?

Accepted Answer

120%

Answer

NEC 705.12(B)(2) limits the total supply to 120% of the busbar rating when the back-fed breaker is at the opposite end from the main breaker.

Question 4

According to UL 1741, inverters intended for utility-interactive operation must have anti-islanding protection to disconnect within how many seconds when grid power is lost?

Accepted Answer

2 seconds

Answer

UL 1741 and IEEE 1547 require anti-islanding disconnection within 2 seconds of detecting loss of grid voltage.

Question 5

Under NEC 690.56, what marking is required on the exterior of a one- or two-family dwelling that has a PV system with rapid shutdown?

Accepted Answer

A rapid shutdown switch location label and a label indicating PV system is present

Answer

NEC 690.56 requires a permanent label indicating the location of the rapid shutdown switch and that a PV system is present.

(NABCEP) North American Board of Certified Energy Practitioners Solar Practice Test

(NABCEP) North American Board of Certified Energy Practitioners Solar Practice Test

NABCEP Code Requirements 3