Just found out that extending a ring main with junction boxes is now no longer allowed in the IEE regs.
Uh Oh.
I have to use junction boxes otherwise I would have to remove fitted wardrobes and the entire bathroom.
Whats wrong with junction boxes? The floorboard above them will be screwed in place and not nailed and marked as an access point for the junction boxes.
Any comments?
Nothing.
Nope. Sounds fine to me. However, I would crimp instead. More reliable and doesn't require periodic inspection.
Christian.
Who/what/where does it say that?
You found out from an unreliable source.
They have to remain accessible, otherwise use crimps.
The phrase
"N.B. This method is now excluded from the IEE Wiring regulations, but remains for reference. "
fro this site
Would it be possible to use additional sockets instead of a junction box? That way you'd make sure the connections are accessible, as well as gaining more sockets!
On the subject of crimps
1) What's the correct way to join 3 conductors (e.g. to create a spur from a ring main) - one size up butt conector? piggy back spade connector ? ring terminal and bolt?2) how do you finsh the job off? Heat srink? Place in an enclosure of some sort? wrap in insulation tape? Presumably where the outer cable sheath has been removed the wires need to be protected by something?
Jim
And, a piece of 2.5 T&E has two different thickness wires - the L&N and earth. Do you use the same size crimp on all three? Or drop a size for the earth? And if you drop a size, what do you do when crimping 1.5mm (and there isn't a next size down readily available)?
Rod
It's a shame these haven't been answered. My experience of screw terminal isn't that good in that copper appears to creep and things can get hot as a result of the loosening. I am aware of crimp connectors for automotive use yet a quick glance at the likes of Screwfix haven't come up with any suitable crimps for fixed installations. Can someone point me in the right direction for crimp connectors and possible housings?
Many thanks. I saw these and assumed they were for automotive use. Is heat shrinking sufficient? Just that it's generally a lot thinner than the original PVC found on Flat T+E cables. Would you put heatshrink around the whole T+E cable?
Then you're not tightening them correctly - it's as simple as that.
Use a screwdriver with the same blade width as the screw, and tighten firmly. If a single cable into a terminal designed for three, double it over. If you're worried about stripping threads, practice first. And use a screwdriver in good condition to avoid damaging the slot.
I accept that. Just that I'm always wary of brass screws and threads. They're not very strong.
They are, for all practical purposes. Like I said, get one and test it to destruction.
"Dave Plowman (News)" wrote in news: snipped-for-privacy@davenoise.co.uk:
Over the years I have had several brass screws fail - typically one half of the head simply flying off. OK - typically duraplugs rather than fixed wiring.
I have just fitted some GET sockets (from TLC) and these have had the firmest, most confidence-inspiring screws/wire clamping I have used. Excellent.
In message , Fred writes
Yeah but the insulation on the T&E has to withstand being pulled through holes, under floors etc. once the cable is in place it's not going to ahve to withstand such mechanical treatment.
I put a length of heat shrink over the whole joint/cable
Re teh comment about sizes, I found that the same size crimop (whatever it was) was fine for the all three wires in 2.5mm T&E
MK plugs - pricey as they are - are a pleasure to wire up; form a loop in the bared flex just large enough to slip over the brass stud (folded in a clockwise-downwards spiral, of course, for compatibility with the stud thread ;-) and screw down the bolts-with-captive-washers till they're nice and snug.
For terminal blocks, rising-clamp construction like the Zeta pieces are several notches up from the cheapies; inbetween are chocblox which have a leaf between the screw and the wire.
Habits vary - as we've discussed here - on 'prejoining' conductors before securing them. Pros frown on twisting together conductors going into the 'tunnels' of a socket, as 'when' you do a full-bore period inspection you'd have to untwist, inducing fatigue. Back in the real world of domestic installs, where sockets are fit-n-forget and go undisturbed from one decade to the next, light pretwisting strikes me as worth doing...
No-name junction boxes, OTOH, are often devilspawn; my most common failure experience with these is the plastick base moulding giving way if you apply a realistic torque to the screw...
Stefek
I would agree wholeheartedly about MK plugs, but regarding sockets I don't honestly think they are (or were) as good.
When I rewired my parents' house - ooh - over 20 years ago I used a mixture of MK and Crabtree sockets, and had trouble with several of the MK sockets - poor contact in the sockets gave rise to overheating, even when using MK plugs and only lowish-power appliances (food mixer, vacuum cleaner, etc). Replacing the offending sockets with Crabtree ones solved everything.
Are Crabtree still about? I haven't seen 'em for years!
Yes - part of the Electrium Group, along with a few other well-known names:
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