How can I fix chewed through wires?

Question

I have two standard two prong wall plugs my puppy has chewed through completely, and he managed to sink his teeth into a laptop cord as well.

I'm thinking the wall plugs are history (a lamp and a fish filter) but hoping I'm wrong and it's an easy/safe thing to repair. I'm cautious since I don't want to wind up causing any fires.

Is there another option other than electrical tape?

I've also been looking at 'heat shrink tubing' for the laptop cord, but I don't think a 'tube' will slip over and still shrink down enough

Answer 1

Many laptop cords are standardized. Where there is no external power supply, they often just need a stock AC cord such as this.

If it is three prong, it may be like this.

If it is damaged, replace it. It is cheap, available at many locations and safe. Do not repair except as an emergency measure.

However, many laptops have an AC cord (the cord that plugs into the wall) that also plugs in on the other end to a power supply (a small plastic brick). The AC wire almost always can be disconnected from the unit and the same replacement technique applies.

The AC cord is on the left, the power supply and its cord on the right.

If the AC cord is damaged, replace the cord.

If the other wire attached to this unit (the wire that goes to the computer rather than the wall) is damaged, this is much more problematic. These wires are almost always not detachable from the power supply, and they are usually proprietary (non-standard connectors). If the damage is very minor, you may be able to get away with shrink tubing, if it fits over the connector (sounds doubtful), or plastic electrical tape (always a bit sketchy on a wire that flexes). This is a low voltage wire, but it still is problematic. You may need to get a replacement power supply from the manufacturer or a third party supplier.

On the other cords, there are two types of replacement plugs, screw on and piercing.

Pierce seems easier, but screw on seems more reliable. They are also available in polarized and three prong versions. Cut the wire above the bad section and bring your old plug to match.

Answer 2

For repairing lamp/laptop/zip style cords, you have this option:

1. Separate the two wires and cut the bad spots out.
2. Slip small shrink tube over each wire. Slip larger shrink tube over both wires.
3. Solder the wires together.
4. Shrink the small tube first, then the large tube.

Use this method if the cord would be too short if you just replaced the plug end.

Answer 3

If the lap top cord is damaged between the transformer and the wall plug you can repair it. The powercord will just be shorter. I would go to your local home center and purchase a replacement plug. Cut the wire at the point of the damage. Install the new plug and you should be good to go.

Answer 4

I can't speak to the laptop cords, but your lamp cords are guaranteed replaceable even if they turn out not to be repairable. If the chewing happened down near the plug your job is super easy. The wikipedia electrical wiring article includes a lot of terminology that you might find helpful.

Can you cut out a length of wire and re-attach the plug assembly?

If your plug assembly isn't damaged (our dear sweet puppy seems to prefer the cable itself) you ought to be able to disassemble it (exactly how depends on the plug, but usually with a little pushing or pulling you can separate the outer casing from the innards and you'll be able to see how the wires connect.

Most 2-wire electrical cord has very subtle ribbing on the insulation on the neutral side. The hot side will be smooth. And if your plug is polarized, the neutral prong will be wider than the hot prong. So you'll connect the neutral wire (with the ribbed insulation) to the neutral side of the plug (with the wider prong).

Would it be better to take out a segment of wire near the base?

With one of the lamps that Bear chewed up, I was able to just cut the cord above his chewing and re-connect it to the same plug. Another, he chewed much closer to the base of the lamp, so I actually cut the wire, pulled it deeper into the lamp base and used twist on wire connectors to connect it to the lamp wire. Again, make sure you connect neutral to neutral and hot to hot. The ribbing on the insulation is your clue! In that case the connectors sit under the lamp base so they aren't visible.

Do you need to replace the whole wire?

If the wire is really not salvageable or would be too short after the repair, you can buy 2-wire electrical cable by the foot at any self-respecting hardware store and replace the whole wire. At the fixture end, the brass screw is hot (so connect the smooth side of the cable) and the silver screw is neutral (ribbed side). As you take the lamp apart, pay attention to how it fits together. Often there are little screws or nuts that tighten the fixture down onto the cable at various points. Loosening those will make it easier to pass the wire through. Feel free to start a new Q with pictures if you need help tackling a particular lamp.

Is the dog really done? We retired a few lamps until Bear outgrew his cable chewing phase, and coated the cable of a few others in bitter apple. I'm sure you've thought of this already, but if you still have a chewy little puppy in the house, you might not want to put your newly wired lamp right back in his reach.

But! Unplug everything first

Finally, if it isn't patently obvious to you that you should unplug everything before you start this project, take a step back and ask a lot more questions before you start.