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Can Mice Eat or Chew Through Romex & Electrical Wires?

Mice. It has been a major problem for humanity for thousands of years. It spreads disease, destroys our crops, papers, and many other things. 

Even now, we could not find an easy way to deter them from our households. Let’s find out if your electrical wires and Romex are safe from them.

Can mice eat or chew through Romex & electrical wires?

Mice can easily eat or chew through Romex & electrical wires. Romex is easier to cut through for mice as it has a minimal insulator. Once the insulator is open, it’s not difficult to cut through the soft copper lines for them. These electrical wire damage can cause short circuits or even fire.

We know mice and rats eat everything. Well, that’s not a complete truth. They need to constantly chew things to sharpen their teeth. Even if the thing is not edible.

But it seems like they have a special attraction to electrical wires. Why so? There might be several reasons.

Electrical wires have the perfect shape to grab and chew with comfort. Some electrical wires also contain degradable plastic made of soya. That also attracts mice and rats.

Romex is the most defenseless type of wire against mice. It contains two or three THHN wires with a grounded copper line. The problem is the insulators of Romex are very thin so mice can easily eat Romex.

Romex has thin polyvinyl chloride (PVC) sheathed and is good for indoor use. Because of the thin PVC layer, it is not suitable for outside use and is mostly used inside homes.

So, a home with mice and Romex is another name of disaster if not taken care of early.

There are many types of cables in our households. Ribbon electrical cables, aluminum shielded cables, twisted pair cables, fiber optics cables, etc.

Unfortunately, no cables are completely safe if there are mice in the house. But a cable with a hardy insulator may protect the wire for a while. 

The problem occurs in the hidden places of the house where those cables are lined and the place also contains some room for the mice. They can make a nest and continue chewing through cables happily. 

They may not chew through cables in one turn if that contains a hardy insulator. But if the mice nest around the cable, they may come back again and again to chew the same cable.

You can save your wires by protecting them with an extra plastic layer. Although it’s not easy. Repealing the mice from your house and sealing all their entrances is the best way to solve the problem.

What happens if a mouse chews through Romex and electrical wires?

Usually, if a mouse chews through Romex and electrical wires, that will cause an electrical outage of a certain part of your house or even the whole home can go out of electricity.

That depends on which wire is damaged by the mice. If the mainline wire is damaged, that will cause a complete electricity outage.

If they cut through other wires that connect to the mainline, it will cause an electrical outage of a part of the house.

However, this kind of damage to the Romex and electrical wires is very difficult to identify and fix. 

Always call a professional in these kinds of conditions. Trying to fix electrical wires without much experience can be highly dangerous.

But if you are unlucky enough, this type of wire damage can cause an even worse scenario. 

In simple words, there are positive and negative wires inside cables that must be separated from each other. 

When a mouse cuts through the insulator, there is a high chance of short circuits. That means those two cables can get connected.

A short circuit can cause tripped breakers. Breakers are used to stop the damage from short circuits. If the breaker does not work, it may cause a fire which is very hard to control as you can’t use water to stop the fire.

Every year this type of home electrical short circuit causes a fire that takes the life of 420 people on average and 1,370 people get injured (National fire protection Association). 

So, as you can see, wire damage by mice and rodents should not be taken lightly. 

If any type of electrical fire starts, cut off the electricity and remove the oxygen source. Call the fire department asap. Do not use water, a fire extinguisher will help the most. 

How to tell if mice chewed through wires?

It’s hard to tell if mice chewed your electrical wires or not. Here are some tips to know if mice are damaging your wires or Romex.

Do not wait:

Do not wait for the signs of chewing. As long as you can detect mice in your house, take steps against them. 

You can’t trust any mouse when it comes to chewing stuff. Most of the time the electrical wire damage remains unnoticed until a disaster happens.

So, taking steps to repel them and protect them from entering your house is the best you can do to stop wire damage and mouse-born problems. 

Check the wires:

Check the wires every month to make sure no wires or Romex are damaged. If you see any damaged wires or teeth marks on the wires, take steps.

Check the wires of the hidden parts of the house. Check the wires by sight or turn off the mainline before touching.

Check other signs:

Check the hidden places of the house and look for signs of mice. If you find any smell, droplets, bitten wood, or anything that indicates the presence of mice, take steps to remove them.

Electrical outage:

If you know there are mice in your house, and suddenly electricity goes out. You can assume mice have done it. 

However, there can be many other problems that can cause electrical outages. If this happens, talk to a professional and let the authority know about it.


You may sometimes hear mice at night. But most of the time they try not to make any noise in our house.

Their wire chewing sound can be noticeable in a quiet place. 

How to keep mice from chewing Romex and other electrical wires?

There are some ways to save Romex and wires in your home. Protecting your house from mice and rats is the best way to stop them from chewing on the wires. Here are some quick tips to deter mice from your house.

Annual rodent inspection:

Some pest clearing agencies can remove all the rodents from your home. They use professional technologies, tools, and advanced methods to do that.

By doing an annual rodent inspection, you can get a rodent-free house. That results will stay if you take further steps to stop mice and rats.

Make your home rodent-proof:

Seal all the holes and cracks so that even a tiny mouse can’t enter your house. A hole larger than 6 mm can be an entrance point for mice.

By sealing out all the holes, no mouse can get out and inside your house. So, you can take further steps to remove them.

Make your house unfavorable to mice:

Know their food source. Do not keep any food outside and even a small part of food should not be left uncleaned in the ground. Cover your trash can all the time.

Set traps:

After sealing your house, and removing all the food sources, you can easily trap them with food and remove them comfortably. You can find various types of rodent traps in the market and online.

However, if there are a lot of them, trapping them can be a long-term process. It’s useless if other mice can enter your house.

How do you fix a chewed wire?

Follow the steps to fix a cord chewed by mice. 

  • First turn off the electricity. Make sure the cable does not have any electricity.
  • Cut off the chewed section of the wire.
  • Separate 2 parts of the wires about half an inch. Do the same with the other wire.
  • Stripe the wires using wire strippers.
  • Insert a heat shrink in a cable.
  • Now connect a cable with another. Use an electrical wire connector to connect. Make sure you are connecting the right cable.
  • Repeat step 6 with the other cable and place the heat shrink. Heat the heat shrink to seal the wire.

Final thoughts

Electrical wires and Romex are mostly defenseless if you don’t take any steps against the mice and rodents. Electrical wire damage must be taken seriously as it can make a fire and take lives and properties. The best way to save electrical wires is to stop rodents from entering your house.