junction boxes

[Stephen]

Hello,

Please can anyone tell me the rules about junction boxes?

I could not find anything in the "old" FAQ and the wiki FAQ's rewiring pages reports an error.

Can you use a junction box if the last bit of cable on your reel is not long enough or should the cable be continuous? Should I save the piece that is too short for another job and start the new reel straight away?

Is it permissible to use junction boxes where you break into the existing ring to add or remove sockets to/from the ring main? Or again should you run continuous cable from socket to socket?

I used google but could only find a US FAQ that says: "Junction boxes must be located in such a way that they're accessible later. Ie: not buried under plaster." Is it acceptable to use them under floor boards provided they are secured to a joist with at least 50mm from top and bottom of the joist? Ort is under the floor considered inaccessible? How accessible is accessible?

Thanks, Stephen. (still waiting for the on site guide to the 17th..., but could not find anything in the 16th when I looked)

[Dave Plowman (News)]

I'd keep unnecessary connections to a minimum. Good practice on anything.

Same as above. But if breaking into an existing ring if might be the only practical way. With care you can use a junction box with not actually breaking the original ring if adding a spur - just removing insulation where needed.

Under floor broads is fine.

[Steve Firth]

Extremely easy women?

[tinnews]

I agree with this(and do it) but it does raise one issue/problem, if you don't break the CPC how can you put the mandatory sleeving on it?

[Andy Wade]

It isn't actually - or at least it's now a strongly deprecated practice in some quarters. All joints made using screw terminals should be accessible for inspection and, with the popularity of wooden floor finishes that can only be lifted destructively, organisations like NICEIC etc. won't allow their members to use traditional JBs under floors unless there's easy access from underneath.

To the OP: If you're altering a socket circuit and can't avoid a joint then it's better to use crimping - see the FAQ

(crimped connections housed in a ChocBox is another possibility). Putting in an otherwise unnecessary joint just to use up the end of a reel of cable would be looked on as very poor practice.

[neverwas]

Is there any kind of *unconventional* JB which is acceptable (or less unacceptable) in such locations please? I ask as I have a JB under floorboards in a bedroom where cabling for 2-way light switches wd have been difficult (for me) without it - and I thought at the time that they were still perfectly OK. (The pain was that the only nearby light fitting has the cable through a joist so I couldn't use a JB which goes through the hole for a dry-lining box and so be accessible from below.)

[Dave Liquorice]

Fold it back on itself and have the the ring cables entering the box through the same hole?

[meow2222]

Although chocboxes are getting used I dont think theyre compliant, as they're thermoplastic. Wiring junctions need to be in... I forget the exact phrase, but basically some type of fire retarding box.

If the joint needs to be buried, it can be soldered or crimped. Screwed. can become screwed in time, so access is needed for them.

NT

[Chris J Dixon]

I had to pull up the electrician doing my kitchen wiring. At the time he was linking out a redundant drop in the existing ring circuit, working from below the upstairs floorboards, most of the ceiling already having been pulled down (in preparation for re-boarding & skimming).

I spotted that he had installed a JB, and pointed out that the boards had not been lifted, and in any case, there was no way of reaching that particular point from above. He changed it for a crimped joint, but I shouldn't have had to intervene.

Similarly, if I had been picky, I could have jibbed at having myself to re-identify the circuit changes made at the consumer unit.

The guy was generally both capable and flexible, but it alarmed me that I seemed more aware of some significant points than he was.

Chris

[Dave Plowman (News)]

To be perfectly honest I think this distinction between JB and crimps was invented by some office wallah. If a JB connection is properly made it won't come loose - so the need for inspection is no greater than any other. Indeed, if a 'sparks' is incapable of tightening a screw terminal properly, is he capable of making a decent crimp?

[unopened]

How does one tighten a screw terminal properly? It's a genuine question, as I've seen variations in technique from the 'finger tight

• 1/8 th of a turn' to 'apply as much torque as humanly possible without shearing off the screw head, in combination with the phrase, "There, that'll fix the bugger."'?

If there is a BS applying to screw tightening, so much the better. Any reference?

Cheers,

Sid.

[Owain]

Obviously, you use the second technique for something which you don't plan to undo again in a hurry, but subsequent events prove it needs to be undone again almost immediately.

Owain

[Dave Plowman (News)]

With brass, 'till it groans. ;-) Finger tight plus 1/8th isn't anything like enough to push things fully home and apply enough pressure.

[neverwas]

I know it's bad from to reply to my own but has anyone experience of the "maintenance free" JBs from Ashley (see eg

I'd need to use 2 in place of a traditional 6-terminal JB but they look a possible solution (without my having to learn how to solder 3+ cables to IEE standards).

Failing that, what's the IEE/NICEIC line on a traditional JB which has its terminals tightened by a gorilla and is then filled with epoxy resin?

[PCPaul]

"Two grunts and a fart" as it's known around here.

[unopened]

if John Rumm happens to read this, perhaps putting something into the wiki might be in order?

Another suggestion for the Wiki is instructions for wiring plugs.

If you look here:

here:

makes me think there's a few things that the average technophobe might not appreciate - such as minimising the amount of visible uninsulated conductor; and not 'overtightening' the screw terminals (without saying how you'd know if they were overtightened or not). Making someone afraid of overtightening is more likely to result in loose connections, I would have thought.

Anyway, just a thought.

Regards,

Sid

[Frank Erskine]

"By law in the UK, all new electrical products must be supplied with a fitted plug."

This only applies to domestic-type equipment, and to portable products. For example an electric shower wouldn't be fitted with a plug (I hope!).

I've purchased theatrical lanterns and these didn't have fitted plugs (they're very rarely used with 13A plugs anyway).

[unopened]

Good point. Maglites don't come with 13A plugs either.

I hope nobody looking for advice on how to rewire a plug tries to follow these instructions:

's easy to forget websites are visible globally.

Cheers,

Sid

[jgharston]

" Cross your fingers and insert the new plug into the wall, and watch your appliance go. "

-- JGH

[Andy Wade]

That reminds me of 'Clix' plugs which readers over a certain age will well remember...