Solar safety boundaries
Residential PV troubleshooting starts with hazard isolation, not hardware access. Follow these boundaries before touching disconnects, rooftop conductors, or inverter equipment.
PV conductors are live in daylight
Array wiring remains energized whenever irradiance is present, even if the inverter is off. Never unplug MC4 connectors under load, and do not open rooftop combiner or rapid-shutdown equipment unless you are qualified and isolated.
Inverter fault smoke or arcing means stop immediately
Burning odor, visible arcing, or heat at the inverter/disconnect is an emergency condition. Use only externally accessible AC disconnects, evacuate, and call emergency services plus your installer.
Roof work carries higher injury risk than wiring
Most residential solar incidents are fall-related. Use rated anchors, stable ladders, and weather hold rules. Avoid roof diagnostics during rain, high wind, or poor visibility.
Rapid shutdown does not equal zero energy everywhere
NEC rapid-shutdown systems reduce conductor voltage outside the array boundary, but array-side equipment can remain energized. Confirm model-specific shutdown behavior before approaching conductors.
Service-panel and meter work requires licensed scope
Backfed breakers, line-side taps, and meter/disconnect modifications are AHJ/utility-controlled tasks in most jurisdictions. Do not perform panel upgrades or utility-side changes as homeowner DIY.