Crimping

[DerbyBorn]

A friend (some years ago) managed to drill through a ring main cable in his kitchen. An electrician fitted a box and blanking cover and re-wired the section down to a socket that was fed by this damaged cable.

He would like to do away with the blanking plate as he wants to position a cupboard that will be half over where the blanking plate is and do some tiling.

I seem to recall that properly crimped connections are permitted - and that these can be buried in plaster (with a bit of protection).

Can someone point me to the authoritative information on this? He will be using an electrician - but wants to instruct the work correctly as one electrican has already wanted to re-wire back to another room and the disruption is not considered worthwhile.

[John Rumm]

(includes link to appropriate section of BS7671 17th edition)

[newshound]

I believe I am right in saying that soldering is also acceptable, and sometimes you can do this where there isn't enough room or spare cable to crimp. Ideally you would double sleeve with heatshrink, one for each conductor and one over-sleeve. I've done repairs where I've used PVC tape or self amalgamating tape for over-sleeving, although I don't know how strictly compliant this would be.

[John Rumm]

Yup soldering is ok as well with adequate mechanical support and insulation...

[Lobster]

On 30 Dec 2013, DerbyBorn grunted in news:XnsA2A6D03E3331TrainJPlantntlworldc@81.171.92.236:

I had a similar problem myself a few years back when I had to get an electrician (NICEIC qualified, etc) in to sort out a wiring problem, which turned out to have been caused by a previous occupier of the house having put a picture hook through a buried cable. Regardless of what I tried to say about the regs, he was adamant that crimping/soldering etc was unacceptable and the whole cable run had to be replaced (which, to be fair, he managed to do very effectively).

You might find similar... possibly worth asking the question over the phone as a hypothetical before engaging a particular electrician.

(One thing I've learned over the years is that however tactfully it's done, tradesmen do not like having a layman telling them about regulations...!)

[tony sayer]

In article , Lobster scribeth thus

Crimps are fine used them for years on many differing projects currents cables and voltages and never a problem. However do use decent ratchet crimpers like this,

But NOT like these useless ones;!..

[dennis]

Ratchet crimpers are only better if they are adjusted correctly. They can produce a poor joint if they aren't adjusted correctly. The correct setting depends on the wire size and they are unlikely to be perfect out of the box.

You can also produce a perfectly fine joint using non ratchet tools if you know what you are doing.

Possibly the worst fault is over crimping the joint as that weakens it but it may not pull out of the connector when you test it.

[Vir Campestris]

Having just put a couple of crimps on with a pair just like the latter - they need a bit of welly on the squeeze, but the crimp didn't want to come off. What's the problem with them?

Andy

[tony sayer]

Dennis.. Used that type and some very slightly larger ones for years. Never had to adjust them and never as yet had a duff joint. IIRC the ones you do have to adjust are these way outside the realm of DIY applications!...

[tony sayer]

They don't put sufficient overall "size" pressure on the crimp ..

When crimped as they oughta be its a sort of cold weld..

[dennis]

You can adjust the tool station one.

[fred]

In article , tony sayer writes

And because you never know whether the pressure applied on a non ratchet tool has been enough to complete a proper joint. If not then you don't get a gas tight joint and don't find out until it goes high resistance later (thro' looseness or corrosion) and the joint or the loop overheats.

[tony sayer]

In article , fred scribeth thus

Precisely, couldn't have put it better myself;)..

[The Medway Handyman]

"a gas tight joint". Interesting. That phrase is used in the blurb for Wago connectors as well.

It clearly communicates the meaning, but how did 'gas tight' become applied to electrical connections?

[Andy Burns]

Probably started with wire-wrapping tools from the 50's onward, where wire is wrapped tightly round a square-edged post so that the copper is 'crushed' onto the corners and you get a direct metal to metal seal that is indeed gas tight, so won't oxidise.

[fred]

That's certainly where I picked up the term.

[Dave Plowman (News)]

I'd say it was right to do this since it was obviously possible. A crimp etc repair should only be used if it isn't practical to replace the section. In your case this might have meant two lots of crimps to replace the damaged section of cable.

[Andrew Gabriel]

Lots don't actually know the regs, and certainly wouldn't understand the reasons many of the regs exist. They know only what someone else has told them whilst they were training. When I did my BS7671 training, the folks on the course for the second and third times were all electricians who had failed it one or more times beforehand. That doesn't apply to all electricians of course, but there are quite a number of practising electrians who have failed their BS7671 several times and stand no chance of ever passing.

Furthermore, if the guy has never done crimping and/or doesn't have the right kit, then it's probably not a good idea to force it on him.