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?
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.
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".
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.
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.
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.