CSLB C-46 Solar ContractorPhotovoltaic System InstallationMedium
A solar technician is performing a final inspection of a roof-mounted PV array. They notice that the module frames are not bonded to the racking system, and the racking system itself is not connected to the equipment grounding conductor (EGC). What is the primary safety concern with this improper grounding installation?
- APotential for electric shock hazard during a fault.
- BPremature degradation of module materials from galvanic corrosion.
- CIncreased risk of lightning strikes to the array.
- DReduced system efficiency due to poor power quality.
Show answer & explanationAnswer & explanation
Correct answer: A. Potential for electric shock hazard during a fault.
Proper grounding and bonding of PV modules and racking systems are critical safety measures. If a fault occurs (e.g., insulation breakdown causing a live conductor to touch a module frame), an ungrounded system would leave the metallic components energized, creating a severe electric shock hazard for anyone touching them.
Why the other options are wrong
- B. Galvanic corrosion is a concern with dissimilar metals in contact, but it's a long-term material degradation issue, not the 'primary safety concern' of improper grounding.
- C. Grounding helps dissipate lightning energy but primarily protects against shock hazards; it doesn't 'increase' the risk of being struck.
- D. While grounding can affect power quality in some ways, the primary concern here is safety, not efficiency.
PV System Grounding
The practice of connecting all non-current-carrying metallic components of a PV system to the earth via a low-resistance path to prevent electric shock and dissipate fault currents.
- Required by NEC for safety.
- Protects against electric shock during ground faults.
- Ensures proper operation of overcurrent protection devices.
Memory trick: Grounding's your shield: 'Shock Stopper' and 'Fault Fighter'!