Can mice chewing wires cause a fire?

Can Mice Chewing Wires Cause a Fire?

Have you been hearing strange scratching noises behind your walls and wondering if your home is truly safe? You are right to be concerned, because mice gnawing on your home’s electrical wiring is a leading cause of hidden house fires. This blog post explains exactly how rodents create electrical hazards and provides the solutions you need to protect your property.

How Does a Mouse Create an Electrical Hazard?

Yes, mice can easily start an electrical fire by chewing through the protective plastic insulation surrounding your home’s cables. This exposes the live, energized copper wire inside, which can spark and arc against nearby building materials. Because mice often build their nests using highly flammable items like shredded paper right next to these warm cables, the risk of a rapid ignition is extremely high.

Why Are Mice Drawn to Electrical Cables?

Mice chew on electrical wires because their front teeth never stop growing, and constant gnawing helps file them down. They do not eat the wires for food, but simply use the round, accessible cables as chew toys to maintain their dental health. Since cables are routed through dark, undisturbed spaces inside your drywall, they are perfectly positioned in the exact paths where mice travel.

What Do Ontario Codes Say About Damaged Wiring?

The Ontario Electrical Safety Code (OESC) strictly prohibits compromised wiring, requiring all electrical cables to maintain intact, approved insulation to prevent arcing. Furthermore, the Ontario Building Code (OBC) mandates proper fire-blocking and clearances inside insulated walls to contain potential fire hazards. If rodents strip the insulation off your wires, your home immediately falls out of compliance and becomes a significant safety risk.

How Common Are Rodent-Related Electrical Fires?

Rodent damage is a massive contributor to structural fires, especially in rural and residential settings. The National Fire Protection Association estimates that rodents cause 20% to 25% of house fires where investigators cannot find a specific origin. Additionally, data from the Ontario government shows that electrical faults cause approximately 40% of barn fires in the province, a risk heavily multiplied by high rodent concentrations.

What Are the Warning Signs of Rodent Damage?

The most immediate sign of electrical damage is experiencing unexplained power fluctuations or frequently tripped circuit breakers. If your lights are randomly flickering or your microwave loses power without warning, a mouse may have chewed through a vital connection. You might also notice a faint burning smell coming from your outlets, alongside physical signs like small droppings near your baseboards.

How Can You Protect Your Property?

As a professional master electrician, I highly recommend installing Arc Fault Circuit Interrupters (AFCIs) in your electrical panel to combat this danger. Unlike standard breakers, AFCIs are specifically designed by Canadian safety standards to detect the microscopic, erratic sparks caused by chewed wiring and cut the power instantly. Once you hire pest control to eliminate the mice, a licensed electrician must inspect your vulnerable areas to replace any compromised cables.

Contact Us

If your lighting is acting up, having a designated master electrician inspect your electrical system is the safest course of action. Are you noticing any of these brighter lights flickering or humming, or is the brightness constant? Call us at 416-838-9006 or visit our contact page — we will be happy to help.