A solar contractor is installing a ground-mounted PV array on a commercial property. The array structure will be constructed using galvanized steel. According to the National Electrical Code (NEC), what is the minimum acceptable method for bonding the non-current-carrying metal parts of the PV array structure to ensure proper grounding?
- APainting the structure with conductive paint and connecting to the grounding electrode.
- BRelying on the mechanical connections of the steel frame for continuity.
- CUsing listed bonding jumpers or devices to connect sections and then to the grounding electrode system.
- DConnecting each module frame directly to a dedicated grounding rod.
Show answer & explanationAnswer & explanation
Correct answer: C. Using listed bonding jumpers or devices to connect sections and then to the grounding electrode system.
NEC Article 690.43 and 250.110 require all non-current-carrying metal parts of PV array frames and structures to be bonded together and connected to the equipment grounding conductor. This is typically achieved using listed bonding jumpers, lugs, or devices to ensure a continuous, low-impedance fault current path to the grounding electrode system. Relying solely on mechanical connections is generally insufficient.
Why the other options are wrong
- A. Conductive paint is not a recognized method for structural bonding in the NEC.
- B. Mechanical connections alone are often not sufficient to provide the required low-impedance path for grounding and bonding.
- D. Bonding each module frame to a dedicated grounding rod is redundant and not the most efficient or code-compliant method for an entire array structure; a common EGC and grounding electrode system is used.
PV Array Structure Bonding
The NEC-mandated process of electrically connecting all non-current-carrying metal parts of a PV array structure to ensure a continuous and low-impedance path to the grounding electrode system.
- Required by NEC 690.43 and 250.110.
- Uses listed bonding jumpers or devices.
- Ensures safety by providing a fault current path.
Memory trick: Bonding the array, don't delay, for safety's path, come what may!