NABCEP Installation & Safety 3

Question 1

What is the correct procedure for locking out a grid-tied PV system before performing maintenance on the inverter?

Accepted Answer

Open the AC disconnect, apply lockout/tagout, then open the DC disconnect and apply lockout/tagout

Answer

Proper LOTO requires isolating both AC and DC sides: open the AC disconnect first, apply lockout/tagout, then open the DC disconnect and apply lockout/tagout.

Question 2

What does the NEC term 'identified' mean when referring to equipment in Article 690?

Accepted Answer

Listed by a NRTL for its intended use

Answer

'Identified' in the NEC means the equipment is recognized as suitable for the specific purpose, function, or environment, typically by being listed by a Nationally Recognized Testing Laboratory.

Question 3

What is the purpose of a rapid shutdown system (RSS) in a PV installation per NEC 690.12?

Accepted Answer

To de-energize conductors in or on a building to protect first responders

Answer

Rapid shutdown systems reduce the voltage and current in PV conductors inside and on buildings to protect firefighters and other first responders from electrocution.

Question 4

Under NEC 690, which conductor color is required for the grounded conductor (negative) in a DC PV circuit?

Accepted Answer

White or gray

Answer

NEC requires white or gray insulation to identify the grounded conductor in DC PV circuits, consistent with general NEC grounded-conductor color coding.

Question 5

A PV module's Voc is rated at 25°C. How does the open-circuit voltage change when the module temperature drops to -10°C?

Accepted Answer

It increases, and this higher voltage must be considered in system design

Answer

PV module Voc increases as temperature decreases; designers must calculate the maximum Voc at the lowest expected ambient temperature to avoid exceeding equipment ratings.

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

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

NABCEP Installation & Safety 3