Installation & Safety Flashcards

When torquing module mounting hardware, why is it important to follow the manufacturer's specified torque values?

Answer: To ensure structural integrity without stripping threads or cracking frames, while maintaining warranty

Proper torque prevents under-tightening (which allows loosening) and over-tightening (which strips threads or cracks aluminum frames), and manufacturer specs are required to maintain equipment warranties.

A worker is about to connect a second PV string to a combiner box that already has one string energized. What hazard must they address first?

Answer: Backfeed current from the existing string through the new fuse position during connection

When one string is energized in the combiner, connecting a second string can create backfeed current through the new fuse position, risking arcing and injury during connection.

What is the primary reason PV wire (USE-2/PV Wire) is used instead of standard THWN-2 wire for module-level wiring?

Answer: PV wire is rated for direct sunlight exposure and wet locations at elevated temperatures

PV wire and USE-2 are specifically rated for prolonged sunlight exposure, wet locations, and higher temperature ratings, making them suitable for outdoor array wiring.

Which of the following is an example of an engineering control to reduce fall hazards during rooftop PV installation?

Answer: Installing temporary guardrails along roof edges before workers begin installation

Engineering controls such as temporary guardrails physically prevent falls by creating a barrier, and are preferred over administrative controls or PPE in the hierarchy of controls.

What is the function of a ground fault protection device (GFPD) in a PV system?

Answer: It detects unintended current flow to ground and disconnects the faulted circuit to prevent fire

A GFPD monitors for current flowing outside its intended path to ground, and when detected, disconnects the circuit to prevent fires caused by arcing at the fault point.

According to OSHA, what is the required minimum illumination level for general construction work areas?

Answer: 5 foot-candles

OSHA 1926.56 requires a minimum of 5 foot-candles of illumination for general construction areas, warehouses, corridors, hallways, and exitways.

What is the primary purpose of bonding all metal parts of a PV array racking system together?

Answer: To establish a low-impedance fault path so overcurrent devices operate quickly during a ground fault

Equipment bonding creates a low-impedance path back to the source so that a ground fault produces enough current to trip the overcurrent protective device and clear the fault safely.