ECN Forum Forums General Topics of the Trade General Discussion Area Welded Copper Connections

Have any of you welded copper for connections, I'm not talking about exothermic welding(cadwelding), I'm asking about what i assume would be using an oxy acetylene torch. or have any of you came across old welded connections? Does it seam to be as bullet proof a connection as they get? If you have experienced this could you give me your thoughts and any information you think may be pertinent on it. If not, have any of you used cadweld(exothermic) for power connections? Or happened across any?

Thank you

Cadweld was only used for grounding/bonding throughout my many years.

I have not seen any exothermic type connections on any energized conductors.

Perhaps it may be done within the transportation fields. (Railroads)

I haven't seen exothermic connections used for energized conductors, but that could be because you may want to disconnect the ungrounded wires.
But if they exist, ERICO (aka Cadweld) would know about them.
BTW - ERICO stands for Electric Railway Improvement COmpany, which was founded in 1903.

Anyone wanting to see a cool way to install wire terminals is invited to check out https://www.youtube.com/watch?v=KuMkQxdn7OA.

I've actually already asked ERICO about the application, i asked them if they were rated for the use and they without hesitation said yes and that they are rated for(or above) the current and temperature of the wire used with, as you would probably assume.

to the point of disconnecting wires, i was thinking the application may be used for inline splices, like long runs, or hard pulls, cadweld and heat shrink, i figure that would be pretty bulletproof/reliable. not that compression isn't great, but you know, in the name of "better" and "why not".

thanks guys

My question would be about the insulation. Would welding compromise the insulation on the conductors and how are you going to insulate the splice? One layer of heat shrink will not be "covered with an insulation equivalent to that of the conductors" 110.14(B)
That article does identify "welding" as an acceptable method tho.
I suppose if this was more popular method someone would go to the effort to come up with a listed insulation system beyond tape or multiple layers of heat shrinkable tubing. (assuming that is even acceptable to an AHJ).

The Russians seem to favour welding for splicing household-sized conductors in junction boxes. I've seen several Youtube videos on that topic. Here's one of them:
https://www.youtube.com/watch?v=KgOKhfVON4Y (not that I'd recommend his twisting technique, feels much too likely to put too much stress on some conductors, eventually breaking them)

His equipment looks very much like a graphite block wired to a plain welding inverter/transformer.

First, I feel sorry for anyone who may have to open that splice for whatever reason.

Second, what is the purpose of splicing what appears to be small gauge (<10AWG) in that fashion?

Tex, I see that you said they seem to favor that procedure, but why??

Thanks for the link BTW.

1.5 mm2 is roughly 16 AWG and commonly used for circuits up to 13 or 16 amps in Europe. I have no clue why they're using this type of splice but there are so many Youtube videos on this technique that I've concluded it must be popular. The only reason I can think of is that they want to bury these splices in an inaccessible location (one of the videos shows them plasterboarding over a junction box) and most European regulations stipulate that only maintenance-free connections (soldered, welded or crimped) may be used in inaccessible locations. The wording varies a bit, in the UK it's "maintenance-free" while in Germany it's "non-undoable" or "permanent", which rules out Wago connectors. I suppose that wording goes back to when the only real alternatives were either screw connectors or permanent splices (soldered or crimped).

European device boxes tend to leave little room for conductors and splices so junction boxes are somewhat common but customers often dislike visible covers on walls, so I guess that's one alternative. Another would be using deeper device boxes, pretty popular in Germany these days.

Welding is definitely better than twisting and taping, also shown in quite a few Youtube videos from Eastern Europe! BTW, I don't understand any Russian but I think the chap in the video I linked to talks about Wago connectors and probably gives reasons why he prefers welding.

Tex:

Thank you for your input. I like the term "non-undoable"!!

I guess that for inaccessable splices, it's the way to go.

Thanks again Tex & stay safe!!

When I was reworking the boxes in this house after moving in I found quite a few splices that were just twisted and taped. It was an interesting method too. He twisted about an inch of wire, leaving about 3/4" of twist, very tight then there was a 3/4" pigtail of one conductor sticking out that he folded over the twist and crimped down with his pliers.
They were all very neat and done exactly the same way so I assume he learned that somewhere but I have never seen it anywhere else. There was no indication that these joints heated up, even the ones going to the 1440w heaters in the bathrooms. Both bathrooms were remodeled and all of that wiring was replaced. It was easy to spot. The original house wiring was silver paper NM, this was brown plastic NM with the color coded copper (neutrals were tinned). I think it is all gone now.

I'm not sure how this heat shrink doesn't cover it.

https://multimedia.3m.com/mws/media/23074O/3mtm-heavy-wall-heat-shrink-tubing-itcsn.pdf




Also, not that i believe you wouldn't be able to direct burial this splice but my thoughts on the application are in instances where you would use a compression butt splice, or maybe a junction block, all inside enclosures.Thanks for the point on the insulation though, I've only exothermic welded grounding and bonding conductors but i don't remember any kind of damage to the local insulation, definitely gonna look closer next time.

Yes, if done properly twisting is a type of cold weld and very reliable but even back in the day not everyone managed to get that right. The same technique was used extensively in Japanese audio equipment back in the 60s and 70s, it's known as "wire wrap" in that field. In audio it was typically used to connect wires to a post soldered into a PCB rather than joining wires but the physics are the same.

The worst splice method I've personally encountered is looping several small wires around an M3 screw with nut and washer, tightening the screw and taping the whole lot. It was tremendously popular from the early days of electricity into the early 1960s in Austria and these splices fail by the dozen! I've never been to a place with that type of splice that didn't have at least a few loose ones! My first experience with them was pulling a few splices from a box just to get an idea of what goes where, then turning the circuit back on, only to hear a highly ominous crackle and fizzle from that box! Just moving the splices had loosened the connection enough to make it arc! Needless to say I always disconnected all power when leaving from that point until the full rewire was completed!

Wire wrap was also used in industrial equipment of the day. When I worked at GE I 'fondly' recall making up control systems for VFDs using the wire wrap method.
I even have my old wire wrap tool in my box of mementoes...along with my slide rule and drafting triangles.

Wire wrap depends on the sharp edges of the pins biting into the wire as you wrap it. That is not like simply twisting 2 round conductors together.
As for the shrink tube, I still wonder how many of the characteristics of the wire insulation are "equivalent to that of the conductors". What is the temperature rating? 60c? 75c? 90c?

https://multimedia.3m.com/mws/media/23074O/3mtm-heavy-wall-heat-shrink-tubing-itcsn.pdf






https://standardscatalog.ul.com/standards/en/standard_486D


I know there is some junk shrink tubing out there, but your statement has me curious because not that i work with a lot of hard line standard followers but i have never heard of a problem code wise or in practicality of using shrink tubing for splices. have you heard of problems either standard wise or in actual use? /inspector issues? do you think it is a poor application?

thanks

Cool. I guess my problem was that I just saw the unlisted "junk" trying to be used. Good to know.
Thanks.