Why cables get chewed
Squirrels gnaw to keep their constantly growing teeth in trim, and the plastic sheath on a cable is soft enough to be tempting. Wires often run along joists and rafters, which are the same routes squirrels travel across a loft, so a cable can be passed and gnawed many times a day. Cables pushed into insulation near a nest are especially exposed, because the squirrel is already pulling at everything around them.
Where the wiring is in a loft
In many houses the lighting circuit for the top floor runs through the loft, with cables laid across or clipped to the timbers. There may also be feeds to a loft light, an extractor fan, a shower pump or an immersion heater, plus TV aerial, satellite and alarm cables. Older wiring in an interwar house, such as many in Kingsbury, can be more brittle to begin with.
Why it is a fire risk
Once the insulation is chewed through, live conductors can be exposed. Bare wires can short out, overheat or spark, and they sit among dry timber, loft insulation, nest material and stored cardboard. That is why gnawed cables are more than a nuisance, and why the affected area should be checked by an electrician.
Signs of chewed wiring
- Cable with the outer sheath gnawed away, or bare copper showing
- Lights on the top floor that flicker or stop working
- A circuit breaker or fuse that keeps tripping for no clear reason
- A smell of hot or burning plastic near the hatch or an upstairs ceiling
- Scorch marks on cable, timber or a fitting
What to do if you find damage
Do not touch, move or try to tape up a damaged cable. If you can smell burning, see smoke or suspect a fire, get everyone out of the house and call 999. Otherwise, keep out of the loft and arrange for an electrician to check the wiring in the affected area. They can tell you whether a circuit should stay off until it is repaired. Do not keep using a loft light or socket on a circuit you think has been chewed, and do not store anything more up there in the meantime.
Tell whoever goes into the loft
Anyone climbing into that roof space, whether an electrician, a roofer or a pest controller, needs to know about damaged wiring before they go up. Mention it when you book squirrel control, along with where the cables are and whether the loft is boarded. If an electrician has already visited, pass on what they found and whether any circuit has been switched off.
Cables on the outside of the house
Telephone, broadband and power cables that run to the roof are also climbing routes. Squirrels travel along them and occasionally gnaw them where they enter the building. A broadband or phone line that keeps dropping out can have many causes, but chewing where the cable meets the wall is one worth ruling out. The other ways up are listed in how squirrels are getting into your roof.
Is it squirrels or mice?
Mice and rats chew cables too, often inside walls and behind kitchen appliances rather than in the loft. If the damage is lower down in the house, read can mice chew through wiring and pipes and squirrels or rats in the loft. Where mice or rats are the cause, small gaps around pipes and cables can be closed afterwards with rodent proofing.
Once the squirrels are out
Get damaged cable repaired or replaced before the loft is used again, and have the entry point closed so the problem does not start over. Other loft damage worth checking is in what damage squirrels cause in a loft. Squirrel control in Brent is a £280 trapping service.
