NABCEP NEC Article 690 Applications 3

Question 1

NEC 690.47(C) addresses DC grounding electrode systems for ungrounded PV systems. What does it require?

Accepted Answer

A separate dc grounding electrode system or bonding to the ac grounding electrode system

Answer

NEC 690.47(C) requires ungrounded PV systems to have either a separate dc grounding electrode or a bond to the existing ac grounding electrode system.

Question 2

According to NEC 690.41, a PV system arc-fault circuit interrupter (AFCI) is required to protect which conductors?

Accepted Answer

PV source circuits, PV output circuits, and inverter input and output circuits

Answer

NEC 690.41 requires AFCI protection for PV source circuits, output circuits, and inverter input/output to detect and interrupt arc faults in the PV system.

Question 3

What is the primary purpose of the Ground-Fault Protection (GFP) required by NEC 690.41 for grounded PV arrays?

Accepted Answer

To detect ground faults and disable the array or disconnect faulted circuits

Answer

The GFP device detects ground faults in the array and disables the array or disconnects faulted circuits to prevent fire and equipment damage.

Question 4

NEC 690.43 requires exposed non-current-carrying metal parts of PV equipment to be grounded or bonded. Which conductor size requirement applies to the equipment grounding conductor?

Accepted Answer

It must be sized per NEC Table 250.122 based on the overcurrent device rating

Answer

NEC 690.43 requires equipment grounding conductors to be sized per NEC Table 250.122, based on the rating of the overcurrent protective device for the circuit.

Question 5

According to NEC 690.47(A), a grounding electrode conductor for a dc PV system must be sized per which NEC table?

Accepted Answer

Table 250.66

Answer

NEC 690.47(A) references Table 250.66 for sizing the grounding electrode conductor for dc PV systems, same as for ac services.

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NABCEP NEC Article 690 Applications 3