Inaccessible junction boxes
I need to use junction boxes to connect up socket connections (spurs) to a ring main, but these junction boxes will be inaccessible later on. Can I solder the solid cores, and then clamp them under the terminal screws?
If you are soldering, do it the other way round -- screw them in as normal first, and then solder the terminal and conductors together. You should only be considering this if you are already fully competent at electrical soldering. More commonly crimped connections are used, as it's a method which is more likely to produce a good result in less skilled hands, but with the proviso that a good quality ratchet crimper is used.
Where are these junction boxes going?
Junction boxes under floorboards are considered to be accessible - even when gaining access involves removing long floorboards, laminate flooring, two sofas a piano and a complete set of the Encyclopedia Britannica. :-)
If the junction boxes are really going to be inaccessible it's better to redesign the circuit to move them somewhere with access, if only because you can guarantee where any fault will occur.
Spurs are often wired into a socket that is on the ring, which avoids the need for a junction box.
No this is a bad idea as it would be difficult to get a satisfactory joint. Such joints would normally be crimped, but again you need to use the proper tools to get a good joint.
John
Does that include fitted carpets on which are shelving units bolted to the wall?
If so, thats *crazy* - a junction box buried in painted plaster would be far easier to get at.
Or is it accessible as in "I eventually had to go down to the cellar to find them." "That's the Display Department." "With a torch." "The lights had probably gone." "So had the stairs." "But you found the plans, didn't you?" "Oh yes, they were 'on display' in the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying 'Beware of the leopard.'"
I'm sure Douglas Adams would have loved Part P.
Sid
Is there really any likelihood of junction boxes developing a contact fault? As long as they are done up tight enough but not so tight as the screws are bordering on splaying the female socket apart, I can't see how or why a junction box would ever fail.
Well, that's what I'm hoping as I have 2 buggers that are only accessible by pulling down the downstairs ceilings!
:¬)
No problem. I have a Stanley knife and a staple gun in the toolbox. I did have to cut through a downstairs ceiling to get to one beneath the floorboards and under a bath though.
Seen lots of those too. I've even met one with a gas cooker connector screwed through it as well.
So would Kafka.
John
I see a few junction boxes where the connections inside them have failed in some way. Usually these faults are where a conductor has broken off at the terminal which has sometimes then led to arcing within the box.
These problem are, as you suggest, usually the result of defects in the initial installation, such as the connections being under or over tightened. Cross-threaded screws are another common problem.
These are rare events though. Most junction boxes will outlast the rest of the installation.
I wouldn't lose any sleep over it - just keep a large hole-saw handy. ;-)
John
Not by the NICEIC these days, apparently.
This isn't anything to do with Part P, which is flawed for enough reasons - but this isn't one of them.
The message from Andy Wade contains these words:
If they're /that/ inaccessible they'll never know they're there!
Presumably this is NICEIC's interpretation that's changed, rather than the regs themselves.
You don't happen to have a reference or URL, do you ?
John
Yes.
"Connections" magazine, Issue 157 (Spring 2006), page 43 - an article on accessibility of connections, which contains the following:
"[...] However connections required by Reg. 526-04-01 to be accessible should *not* generally be located under a floor where a carpet is likely to be laid. A fitted carpet can effectively render connections beneath the floor inaccessible because of objections from the occupier to the carpet being lifted, or difficulties in finding the access trap."
IMO carpets are the least of your worries. It's laminate flooring, sheet vinyl on hardboard, or even ceramic tiles over floorboards that make such connections _really_ inaccessible.
Hmm....
All a bit subjective, isn't it?
I don't recall NICEIC being given the authority to set standards or even to lay down the rules on their interpretation.
Having said that, one can see some common sense in what is being said.
As I suspected.
That laminate flooring is usually laid _across_ the floorboards doesn't help either. Even vinyl flooring laid over hardboard is bad enough.
I now generally consider laminate floors as being "solid" and design or quote accordingly.
Fortunately the only time I've really had to get under some ceramic tiles there was enough space to crawl under the floor from another room.
Phrases you don't want to hear: No.765 "We've had new flooring put down since you quoted for the work."
John
You are right that they don't set the standards. They do _interpret_ the standards in the field. Their inspectors have something of a reputation for ring-fencing the regs. It would take a lot of courage for a member to challenge the inspector. OTOH the member could change to one of the many (currently nine I believe) other organizations that register electricians. However the NICEIC have positioned/marketed themselves to the point that many members of the general public and many goernment/ngo/commercial 'officials' treat them as if they were the only certification body for electricians.
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