A squirrel on your roof does more than leave droppings. It chews the wiring under the panels, and the first sign is often a fault you cannot see.
Why squirrels chew solar panel wires
Rodents gnaw constantly. A squirrel's front teeth keep growing for its whole life, so it chews to keep them filed down. Under a solar array, the DC conductors and connectors run along the gap between the panel frame and the roof. That gap is sheltered and warm, the same spot pigeons use for nesting, and the wiring inside it is the closest thing to chew.
Rats and mice gnaw the same way, so the problem is not one species. What matters is the location. An array puts file-worthy material inside a protected hiding spot, and the animal works on it whenever it is under there. Tree squirrels live in every East Bay suburb, and the California Department of Fish and Wildlife lists them among the state's nongame wildlife.
How to tell if rodents are chewing your wiring
Most of the damage is hidden. The chewed conductors sit under the panels, so the signs usually reach you indirectly. The clearest is an inverter error code or a tripped breaker with no other explanation, especially an arc-fault alert. Modern systems detect a DC arc and shut down to protect the roof, so a repeated arc-fault message is a strong signal that something under the array is damaged.
A system that was running fine and then goes offline, in a neighborhood with mature trees, points the same direction. From the ground you may see nesting debris, droppings, or a squirrel crossing the roofline. Confirming chewed wiring usually takes someone on the roof, because the damage itself is out of sight.
What chewed wiring does to your system
Chewed insulation exposes live DC conductors. A damaged conductor can arc, which is an electrical spark jumping a gap, and a spark next to dry nesting material is a fire risk. Because that risk is real, the National Electrical Code requires arc-fault protection on a building solar system's DC circuits, under NEC 690.11. The protection detects the fault and cuts the circuit.
A chewed array usually shows up as a shutdown before it becomes a fire. The inverter trips or throws an error, and the system stays down until someone repairs the wiring. That shutdown is the protection doing its job. The wiring still needs repair, and until it happens the system is offline.
How to stop it
Critter guard mesh seals the gap between the panel frame and the roof, so the animal never reaches the wiring. The guard is galvanized steel mesh attached to the frame with clips, nothing screwed through the panels or the roof, so the equipment warranty stays intact and air still flows under the array. It is a one-time installation, and it is the same guard used against pigeons. The cost tracks solar panel bird proofing cost; if you already have pigeons, the guard solves both at once, as we explain in our post on pigeons nesting under solar panels.
A cleaning will not fix chewed wiring
A cleaning removes soiling from the glass. It does not repair wiring, and it will not restart a system that an arc fault has shut down. That shutdown is the part to hold onto: the protection trips to stop a fire, and cleaning does not reset it. If a crew finds chewed conductors, the right move is to flag them rather than clean around them and leave the hazard. Repairing the wiring is a job for an electrician or your installer, and it should happen before the guard goes on.
Total Solar Cleaning installs the critter guard and cleans the panels. We do not perform electrical repair, and we will tell you when the wiring needs a licensed electrician first.
What this looks like in Lafayette, Orinda, and Walnut Creek
Lafayette's hillside, oak-heavy properties give squirrels and rodents direct access to rooftop arrays from overhanging branches. Orinda's wooded hillside homes see the same pattern, where tree-line access lets squirrels reach panels without crossing open ground. Walnut Creek's mature tree canopy and established rodent populations make chewed wiring a recurring finding during cleaning visits.
If your system is throwing an arc-fault or inverter error, or you have seen squirrels crossing your roofline, have the wiring looked at. Total Solar Cleaning installs critter guard across the East Bay and cleans panels with deionized water and soft brushes. Call (833) 444-4173 or request a quote online.