[How] Can I safely repair the nick in this electric cord?
August 11, 2010 8:49 PM   Subscribe

[How] Can I safely repair the nick in this electric cord? Is there anything I can use besides electrical tape?

There is a small nick (pictures: 1, 2) in the insulation of the cord of a small home appliance (20 Watts, polarized 2-prong plug.) For financial reasons I want to fix it rather than replacing it. This is not an appliance that would be left unattended, but I don't want it to catch fire or shock me.

The nick is very close to the appliance end of the cord (rather than the end that plugs into the wall socket) so I can't just cut it at the nick and put a new plug on. And the way the wire attaches to the motor inside the appliance looks rather complicated as well, so I can't just strip some more of the wire and re-attach the stripped ends to terminals inside, either.

How safe is just using electrical tape if the nick is small and the metal wire is still intact? Is there something better/sturdier/more flexible? (Am I correct that I basically just need to use something that has insulating properties and will stay in place?)

I saw a product called brush-on electrical tape but I'm not clear on how much of an insulator it is--packaging only emphasizes that it seals out water. Does silicone sealant have sufficient insulating properties? That's more flexible and would seem to make a better patch/seal. I realize that this is not an approved use and would not be to code, but I'm using this for a personal appliance, not home wiring or an installed washing machine or disposal or anything, so my only concern is safety.
posted by needs more cowbell to Home & Garden (18 answers total)
Do you have a pair of wire cutters and a screwdriver? You can cut off the plug, separate and strip the wires, and install a replacement plug--a couple of bucks at the hardware store.
posted by hydrophonic at 8:53 PM on August 11, 2010

Unfortunately, as mentioned in the question, the nick is too close to the appliance itself to do that. It's less than half an inch from where the cord meets the appliance body.
posted by needs more cowbell at 8:56 PM on August 11, 2010

If the silicone sealer will stick the cord, then yes, it is an adequate insulator. Another possibility is heat shrink tape.
posted by Bruce H. at 9:07 PM on August 11, 2010

Will it insulate sufficiently even if it is directly touching some of the bare wire way down inside the nick?
posted by needs more cowbell at 9:10 PM on August 11, 2010

Is the nick on both wires or just one (it's hard to see from the image)?

If it is just one wire, you are probably ok with electrical tape.

If it is both, I would try to replace the cord.

With the nick on one wire, you just need to separate that one wire from touching something which is grounded, electrical tape will work fine. If it's nicked on both wires, then you need to make sure nothing conductive can short across the two wires - so electrical tape wrapping both would not be adequate - you would have to separate the two wires and it doesn't look like this is possible from the picture...

One thing to remember in these situations - it's not always your safety, it might be the next person who uses the appliance and does not know about the issue who runs into a problem. So just be sure the tape covers the nick and will stay in place (I personally would start to wrap the tape right at the nick, after several times around the cord, I would continue to tape around the V section which apparently enters the appliance to ensure the tape does not slip down the cord.)
posted by NoDef at 9:11 PM on August 11, 2010

Similar to Bruce's reply, I would use silicone or super glue and then wrap it in heat shrink tubing.

I believe that the tubing would help contain the filling material during movement.
posted by Sonic_Molson at 9:12 PM on August 11, 2010

I love that brush-on electrical tape. I've used it for cord repair but also for all kinds of other stuff. It's way durable.
posted by galadriel at 9:31 PM on August 11, 2010 [1 favorite]

I can't tell what it is but judging from the strain relief (the triangular ridged bit) visible in the picture it looks like it's meant to move around. What I would do is:

1) Hot glue to cover the nick.

2) More hot glue to extend the strain relief out past the nick. You need to build up something roughly conical, extending and tapering away from the existing plastic triangle. Right now there is (roughly speaking) a stress concentration right where the nick is, and you need to stiffen the cord there so it will want to bend further out when it's moved.

3) Shrink wrap over the whole thing to keep it in place (you should be able to buy shrink tape you can wrap around and then heat; it won't be possible to slip actual shrink tubing on since there's stuff in the way on both ends.

I would do all of this is some obviously hideous color so it was harder to forget that the repair happened, because you ought to check it every once in a while to make sure it's not wearing, fraying, or (this would be bad) getting warm where you did the repair. From what I see in the picture I don't think any repair you do will last unless you figure out some way to extend the strain relief.
posted by range at 9:32 PM on August 11, 2010

All the solutions mentioned here will provide adequate electrical insulation. Your biggest concern is to be sure the problem does not get worse over time due to the fatigue of normal use.

Since you still have all the insulation intact, you just need something to hold it together. I suggest getting some quality electrical tape (Scotch/3M - it comes in yellow) and applying it properly (Electrical Taping Skills: A Lost Art?). Using the right technique is the difference between a clean, long-lasting repair and a sticky, unraveling mess.

Oh, and I would probably separate the two conductors around the nick to tape it directly.
posted by pants tent at 10:01 PM on August 11, 2010

I would put a tiny drop of super glue in the nick then I would manipulate the cord to close the gap. superglue does a respectable job bonding vinyl to itself.
posted by hortense at 10:30 PM on August 11, 2010

I am not an electrician, I'm just a chick with a couple of toolboxes doesn't have a lot of cash to throw around either.

I'd wrap it securely with tape. That's it. If the wire isn't broken/touched/nicked, then it's only the outer covering you need to worry about. I wouldn't use superglue, why force something alien into the wiring that wasn't there in the first place?

I'd wrap decent electrical tape around it while the cord is firmly pushed 'shut', so the nick isn't spread apart. And I'd check to see it doesn't get hot whenever I used it.

(And then I'd start saving for a replacement, because life is too short to worry about dodgy electrical repairs.)
posted by malibustacey9999 at 3:39 AM on August 12, 2010

Can you cut the cord and install a connector at the break?
posted by A189Nut at 4:02 AM on August 12, 2010

Since it's so close to the strain relief, I would start wrapping heat shrink tape around the strain relief (starting at the device end) down the cord about two inches past the nick. Heat it according to the package directions being careful not to damage the cable any more. This should create a second strain relief on top of the first that should protect the nick from getting worse. You could do one of glue filling or liquid tape methods first if you are really concerned, but the key here is to prevent bending the cord too much.
posted by buttercup at 6:23 AM on August 12, 2010

"I saw a product called brush-on electrical tape but I'm not clear on how much of an insulator it is--packaging only emphasizes that it seals out water."

This is good stuff and you can build several layers for added protection. I've used it quite a bit. The other option is self vulcanizing electrical tape but it'll be awkward to use with such little clearance.

I'd avoid super glue as it's too brittle and avoid regular silicone because the acid it gives off while curing can corrode the wire. And I'd be leery of hot melt glue; some are UL listed for electrical purposes but some are conductive.
posted by Mitheral at 7:53 AM on August 12, 2010

I came in to give Mitheral's comment. Hot glue is also pretty fragile to mechanical stress. I would avoid it similarly. Tape and/or liquid tape would be my solution. If you can get a heatshink tube over the plug-end that might work, but to get one that will size properly to the cord, you often need to cut the plug off which is just making the situation worse, IMO.
posted by bonehead at 10:00 AM on August 12, 2010

> If you can get a heatshink tube over the plug-end ...

Which is why I recommended heat shrink tape instead.
posted by Bruce H. at 12:35 PM on August 12, 2010

I ended up rigging something up with electrical tape ($0.99) and a foot of clear vinyl tubing ($0.41) (that I happened to see at the hardware store) placed over it for more protection and to avoid further stressing the area. Silicone worried me due to Mitheral's comment about acid, hot glue involved buying a glue gun, liquid tape was $10.00, and heat shrink tape was also expensive, so those started to get into territory of "just spend the money on replacement instead." Which I'll do eventually, but this will do for now.

Thank you for all the ideas/comments, especially for drawing my attention to the need for strain relief at the point of the nick and for making me feel like this is a sufficiently safe solution as long as the tape stays on.
posted by needs more cowbell at 2:24 PM on August 13, 2010

And thank you for the feedback.
posted by Bruce H. at 4:48 PM on August 13, 2010

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