I was always under the impression that wire nuts created a better electrical connection than using electrical tape. I'm still under this impression and I think it is correct. However, I was taking apart a junction box in my basement last night and found a connection that piqued my interest. This is older wiring, so I was a little bit worried that maybe it was aluminum wiring, but it looks like it is copper. However I am unsure why there would be the coating /solvent / solder on here. The whole thing was then wrapped up in electrical tape. Is there a reason that this wasn't connected using a wire nut? It's not aluminum wiring, right?enter image description here

  • 3
    It looks like a bad attempt at soldering, followed by the leftover gunk of the tape's adhesive.
    – brhans
    Mar 20, 2018 at 21:59
  • 2
    Whoever did it had no nuts?
    – freshop
    Mar 20, 2018 at 22:06
  • 3
    It was a thru-wire, and he was tacking additional wires onto it, probably not in a junction box, the thru-wire didn't have enough slack to terminate it in the normal way at a nut. There are several serious problems with the wiring methods here. Mar 20, 2018 at 22:48
  • 2
    Electrical tape is insulation only. Electrical tape does not compress the wires and make a secure electrical or mechanical connection. These are solid copper wires, not aluminum. If you wanted to make a secure connection you could use an electrical "split bolt" connector and then tape it up with electrical tape to insulate it. This might not comply with code, but I think it would be safe. homedepot.com/p/… Mar 20, 2018 at 23:32
  • Never. It needs to be said up top in bold. Don't use electrical tape for making connections.
    – GManNickG
    Mar 21, 2018 at 5:26

4 Answers 4


I tend to agree with the comments

  1. This is an inline splice
  2. Whomever did this was covering solder

So, having said that...

Electrical tape is good for insulating wire. It cannot hold wires together. In this case, the solder is holding the wires, but I really wouldn't trust solder for electrical wires. Wires can get warmer when in use, which could weaken or break the solder.

Wire nuts involves twisting the wires together, meaning the wires hold themselves in position, The nut insulates the top and helps (somewhat) stop movement.

I would only use electrical tape on a wire that has had its insulation damaged.

  • 1
    I'd be willing to warn that electrical tape isn't even good at insulating wire either? (although, its something we do. If this was a good solder connection, then tape (could) do the trick, but still wouldn't be allowed. Even a wire nut can feel the pain under heat/cool cases. I've often seen E-Tape be used ON wire nuts, messy to work on when tape gets older, but perhaps it adds some piece of mind.
    – noybman
    Mar 21, 2018 at 1:56
  • 3
    A proper solder job is code. That isn't one. It also isn't code because it isn't in a proper junction box, noting the background does not resemble a junction box. (unless he cut this specimen completely out of his wiring and set it on a benchtop). This job belongs underneath a model railroad, not carrying mains. Mar 21, 2018 at 18:11

This is dodgy work

Your house may have a lot of it. If this is your first time laying eyes on electrical work, don't normalize it.

What happened here is the inline wire was pre-existing, and the hack decided to add 3 wires to it. So he peeled back some insulation, and lacking any other way to attach the wires, spiraled them around and soldered them. This would be legal in Knob-n-Tube wiring in 1924. However in that case the 1924 person soldering it would have soldered 100 connections a day, and would've rolled off yet another perfect one. This was a one-off done by a person with no experience soldering mains sized wires, not even the right soldering iron!

The wire is also weird. Most house wiring is done with cable, i.e. NM (Romex) which has no markings on the conductors. Some wiring is done with single wire (THHN/THWN-2) but you can't do that loose, it's required to be run in raceway or conduit, i.e. junction boxes. Also the coating is incorrect for THHN and the blotchy red markings don't resemble THHN. It looks more like low voltage/automotive wire.

Honestly given the wire, and the wiring methods, and the background, this resembles to me feeder wiring on large model railroads, i.e. that run underneath the benchwork. For that application, this would be acceptable. If this is an "identify this wiring" question, final answer.

Soldered connections, properly

First, a proper job is done of soldering it, which wasn't done here.

Then, there's a "best practice" with electrical tape which is essentially a lost art. It involves double-layering vinyl electrical tape with the old cloth "friction tape" (which I can't really describe if you don't know what it is). Properly done, it's a masterpiece, like a served guy wire connection.

You didn't state which wiring method was in use in this location, so I can't comment on whether solder is legal with this wiring method.

  • Thanks for your feedback. I don't have much experience with electrical but I'm learning it. The wire itself is in a black sheath and has a red/white wire inside and then a black wire. It looks relatively normal to me, just older. I'll take a picture of it when I get home. Now you've got me a little concerned about the wiring throughout my house, which is about half this stuff and half 12/2 romex. Mar 22, 2018 at 13:12
  • here's what it looks like. imgur.com/a/RFzji Mar 23, 2018 at 13:07

This looks disgusting.

What worries me is why there is so little solder there. It could be whoever did this was trying to save on solder, but that would be weird, as it isn't that expensive.

Clue: the insulation on the wire at the left side of the picture is burned.

When doing this kind of soldering, you need a high-power iron (like >100W soldering pistol) which will quickly heat the wire and allow you to do the job without burning the insulation too much. It might melt just a little bit... but this one looks like it's been barbecued to a crisp.

This looks like someone had an underpowered soldering iron and left it there for a looooong time (while the insulation started to burn) until he finally could manage to melt a little bit of solder, then called it a day.

It's a bit counter-intuitive but a powerful soldering iron will allow you to do a good solder before the heat travels too far into the wire and burns the insulation.

I'd be worried about a cold solder joint, which may crack or turn into a loose contact.

I was always under the impression that wire nuts created a better electrical connection than using electrical tape.

Besides solder, if you want a good connection you need something that presses both conductors together with a very strong force. A wire nut does this, in fact the metal "helix" inside applies so much force it's similar to a crimp. The metal "helix" inside is like a self-tapping nut. When you screw it on the wires it will bite into them and hold them together.

Tape around wire is only insulation in the best case, after a few years when the adhesive degrades it's more like decoration, it doesn't help the contact in any way whatsoever.

It's not aluminum wiring, right?

No, it's copper.

Doesn't change the fact this is crap.

If you want to redo it, don't solder unless you know what you're doing and have proper tools. Also the wire looks very oxidized which won't help.

I'd just cut it off, clean it up and put a legal connector (wire nut or wago).


Well i dont think they use shrink tube in house wiring, but if you had zero slack on the wire, thats what I would do. Put some heatshrink on one side loose, and then do some kind of solder and heat shrink it up so no one could see the mess. But yeah wire nut or even better are those new locking connectors (lever lock quick connect terminal blocks according to search engine) for all connections that might one day need to be removed.

The person who did this wanted it to be permanent, perhaps to simply extend a short wire if its in a box. Has nothing to do with better electrical conductivity. But really who can get in the mind of the electrical taper? not me! just fix it if you can or re wrap that sucker and hope it is out of the way... I'm not sure i have seen soldered mains wire in any apartment or house i have owned... The risk is obviously it shorting out (poor insulation, insufficient tape, etc), people tie copper wire together all the time and its fine. But the exposed copper is generally inside something, like a wire nut.

  • 2
    Welcome to Stack Exchange. It is not at all clear that you've posted an answer here. This type of connection definitely should not be ""re-wrap that sucker and hope it is out of..." it is a situation requiring repair.
    – noybman
    Mar 21, 2018 at 1:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.