CSLB C-46 Solar ContractorPhotovoltaic System InstallationEasy
A solar technician is inspecting the electrical wiring of a PV array on a commercial rooftop. They notice several DC homerun conductors are routed through an open metal conduit exposed to direct sunlight. What is the primary risk associated with this installation practice?
- AIncreased risk of ground fault current due to moisture intrusion.
- BIncreased voltage drop due to conductor inductance.
- CReduced open-circuit voltage (Voc) of the PV strings.
- DAccelerated degradation of conductor insulation due to excessive heat.
Show answer & explanationAnswer & explanation
Correct answer: D. Accelerated degradation of conductor insulation due to excessive heat.
Open metal conduits exposed to direct sunlight can act as heat traps, causing the conductors inside to operate at elevated temperatures. This excessive heat can accelerate the degradation of the conductor's insulation, leading to premature failure and potential safety hazards.
Why the other options are wrong
- A. Moisture intrusion is a risk if the conduit is not properly sealed, but an open conduit in direct sunlight primarily poses a heat-related risk.
- B. While inductance can affect voltage drop, direct sunlight on an open metal conduit primarily causes heat gain, not a significant increase in inductance.
- C. Open-circuit voltage (Voc) is primarily dependent on cell temperature and irradiance, not directly on the conduit's exposure to sunlight.
Conduit Heat Effects on PV Wiring
Conductors routed through conduits, especially metal conduits exposed to direct sunlight, can experience elevated temperatures that accelerate insulation degradation and reduce current carrying capacity.
- Sunlight heats conduit, transferring heat to conductors.
- High temperatures reduce conductor ampacity.
- Excessive heat causes insulation to become brittle and crack.
Memory trick: Hot Conduits Cook Insulation.