Dummies Guide to Domestic Electrical Work

You must put the splices in boxes and those boxed MUST BE PERMANENTLY ACCESSIBLE.

Absolutely correct all junctions need to be accessible or repull the wiring. I know it is a pain, safety first and always when it comes to electricity. After all you are sleeping in this home....

You have to say which country you are in. You look like you are in the UK, and the two US answers you got are not the case for the UK.

Cables should go through the joists in holes at least 2" below the top of the joist (and at least 2" above the bottom if the joist also has a ceiling attached to the underside).

Why did you cut them? Oh well, a bit late now, but you may well have made it non-DIY repairable unless you can solder or crimp cables.

As the join is inaccessible, it must be crimped, soldered or brazed (crimping is the most common way, and brazing is not appropriate for standard Twin and Earth cable). The join should also be in a suitable enclosure. If you are crimping, you can use a large junction box as the enclosure and simply ignore all the terminals. If you are soldering, you can use a junction box as normal, and then additionally solder the conductors to the terminals. Unless you are experienced with crimping or soldering and have the right tools, you shouldn't attempt either.

Obviously, pulling through a new piece of cable would be a better solution than making a join, if that's possible.

There would appear to be another fault which you have not found or you have introduced. This seems like you will need to get an electrician in anyway.

OK, good advice - I am in the UK so will will focus on Andrews comments:-

2 - I cut them because it seemed safer than leaving live cables with nail holes in the insulation. However note use of the word 'dummy' in title!

In light of the good advice given I will now endeavour to place these junction boxes in accessible locations, and will at a later date re-visit when I get on to fixing the faulty light / calling in a real electrician.

So - final questions : what is involved in crimping and does my suggested solution sound sufficient to avoid shock or fire risk?

Thanks!!!

i.

That's normally good enough to ensure they don't get nails through them. In old or less well installed installations, notching the top of the joist for cables is the usual way they get nails through them at some later stage.

You need to buy some insulated crimps matching the conductor size, and a ratchet crimping tool. You should make up perhaps 10 or so good crimped practice joins before doing the real ones. You really need someone to inspect them and tell you if they're good or not. You should still ensure the joins are in a reasonably fire-proof enclosure such as a junction box.

I don't understand -- don't you need to join the cables back together? It's fine if you don't need to.

It does have to be said that the rule about making joins accessible (unless crimped, soldered or brazed) is not one which is well known or understood by electricians -- plenty of them break it.

Since I can't inspect the quality of your workmanship, I can't comment on the likely shock or fire risk. It would certainly be possible to do the job badly enough that there was an increased risk.

Andrew,

Ah - I think I may have been a little unclear in my description. I'm not looking to reconnect any severed cables. Just tidy and terminate all ends so that any risk is reduced. It's surely wrong to leave mains cables just taped up, so I want to do the right thing and tidy them up safely.

Therefore no need to crimp - I'll just put ends into separate junction boxes.

Thanks for your help and advice, much appreciated.

i.

If you can find the "other ends", disconnect and insulate them. Better - if you can do it - remove the other ends from their junction boxes.

"other end" ------------ cut ------------ "other end"

You know where the cut is. One of the "other ends" goes to the light that stopped working. The remaining "other end" goes to a location that is a source of power - either the service panel or another junction box. I think it is worth the effort to locate the "other ends" and disconnect them. If you can remove them from the junction boxes, that's best - and you wouldn't need to put the cut ends in accessible junction boxes.