Breakers trip for no clear reason. An outlet stops working. A burning smell appears near a wall. Rodents are one possible cause, and in older Scranton homes with old wiring and old gaps, the two problems often arrive together. This guide explains why rodents gnaw wires, the signs of chewed wiring, and the order for fixing it: make it safe, remove the rodents, seal, then repair.
Short answer: Rodents gnaw wire insulation because their teeth keep growing. Gnawed insulation can expose live conductors, raising short and arcing risk, especially near nesting material. Call an electrician for damaged wiring, and pair the repair with rodent removal and sealing so repaired wiring is not chewed again.
Why do rodents chew wires?
Rodent incisors grow continuously, so mice and rats gnaw constantly to wear their teeth down.
Wood, cardboard, plastic, and wire insulation all get gnawed. In a wall void or attic, wire insulation is simply in the way. Gnawing does not mean the animal is eating the wire. It means the wire sits along a run, near a nest, or across a gap the animal uses. That is why chewed wiring shows up in the same places as droppings, nesting material, and rub marks. The mice removal page and rat removal page describe the signs that accompany gnawing.
What are the signs of chewed wiring?
Tripped breakers, flickering lights, outlets that stop working, a burning smell, visible gnaw marks on insulation, and droppings near wiring.
A single tripped breaker can have many causes. The rodent pattern is a breaker that trips repeatedly, damage near droppings or nesting, and gnaw marks on insulation or junction boxes. In an attic, chewed wiring may sit near nesting material in insulation. In a basement, it may sit near pipe and foundation gaps. Do not touch damaged wiring with bare hands. If you see exposed conductors, scorch marks, or a burning smell, treat it as urgent: keep clear, and call an electrician.
Can chewed wires start a fire?
Gnawed insulation can expose live conductors, and exposed conductors can short or arc, especially near dry nesting material.
That mechanism is the real risk. This site does not publish a percentage of fires caused by rodents, because no primary source for such a figure was found in the research. What matters for your home is the mechanism: exposed wire plus nesting material plus a void nobody looks into. An electrician can assess the wiring; a rodent inspection can find the gaps and nesting that explain it. Either trade alone sees only half the problem.
Who do I call first: exterminator or electrician?
If wiring looks damaged, call an electrician first to make it safe. Then pair the wiring repair with rodent removal and sealing.
The sequence: first, safety. An electrician checks damaged wiring, turns off affected circuits if needed, and advises on repair. Next, rodent removal and sealing, so repaired wiring is not chewed again. Then, wiring repair or replacement, once the animals are out and the gaps are sealed. Finally, monitoring, so new gaps and new activity are caught. Doing the wiring repair before sealing invites a repeat: new insulation and fresh wire in the same open gaps. Doing sealing before the electrician checks the wiring can leave damaged conductors hidden in a sealed void. Both trades need to know about each other. The attic cleanup page covers wiring checks after attic work, and the basement page covers foundation-area wiring runs.
Does homeowners insurance cover chewed wiring?
Standard homeowners policies commonly exclude damage by rodents. Check your own policy and talk to your insurer.
This is general information, not insurance advice. The common pattern is that standard policies exclude damage by birds, vermin, rodents, or insects, treating rodent damage as gradual and maintenance-related rather than sudden and accidental. Secondary damage may be treated differently depending on the policy. Do not assume coverage in either direction. Read your policy and ask your insurer before relying on it. The cost page explains why paying for inspection, sealing, and monitoring is often the alternative to paying for repairs out of pocket.
What to do next
If you see exposed wire, scorch marks, or a burning smell, keep clear and call an electrician. If you see droppings, nesting, or gnaw marks near wiring, book an inspection and tell both the electrician and the rodent provider about each other’s findings. Sealing is covered on the exclusion page.
Sources: CDC and EPA rodent guidance; electrician and pest-control guidance on rodents and electrical safety. No fire-percentage figure is published here, because no primary source was found. General information, not electrical or insurance advice.