I understand there are two main methods of rewiring a domestic property lighting circuits. Ceiling rose and junction box methods. We were wanting to go the junction box method, however, it seems that if the JB's are being located beneath the floor boards on the first floor to provide the required cables for the ground floor and the first floor is going to be carpeted throughout, then we would not be permitted to rewire this floor the JB method. Is this correct? Hope someone can clarify this. Thanks. (If I haven't confused everyone}.
Rewiring domestic light circuit
- Thread starter Liamondo
- Start date
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It's correct that you could not use traditional JBs (with screw terminals). However, if you really wanted to, you could do it using 'maintenance-free' JBs.
Having said that, why do you want to use JBs? Using the 'loop-in ceiling rose' method leaves all the connections accessible, which will/would make very much easier for you if there ever were a need to modify or extend the circuit, not to mention easier fault-finding in the case of any problems.
Kind Regards, John
The JB method was intended for use with ceiling roses that did not contain loop terminals.
Since they all do now, that method has been obsolete for decades. It also costs more, takes longer and as you have found, can't actually be used if the junctions are concealed under the floor.
Another option is to loop at the switches, which is desirable where other light fittings are used that have no space inside for connections.
Since they all do now, that method has been obsolete for decades. It also costs more, takes longer and as you have found, can't actually be used if the junctions are concealed under the floor.
Another option is to loop at the switches, which is desirable where other light fittings are used that have no space inside for connections.
I would be wary of using the loop in ceiling rose method these days. No one wants pendants hanging from ceiling roses any more and many fittings on sale don't have loop in terminals.
There must be many houses with junction boxes under the floor. Is the maintenance free solution actually a regulation or just guidence?
There must be many houses with junction boxes under the floor. Is the maintenance free solution actually a regulation or just guidence?
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I believe it's now a regulation within BS7671 that "inaccessible" junction boxes must be only the "maintenance free" type, although of course BS7671 itself is really just guidance anyway, since there's no compulsion to follow it.
Personally, from what I've seen of the so-called "maintenance free" boxes I'm not sure that I'd trust them to be that anyway, and would be far happier with the traditional screw-terminal box. And what is "accessible" supposed to mean anyway? It seems that a lot of people have taken it that a box under floorboards is not considered to be accessible, but if it's done with future access in mind I would have to question that.
Realistically, how often is one ever likely to need access to a regular junction box after it's installed that, on the rare occasion it might even need to be accessed it would be unreasonable to just lift back the carpet and remove a floorboard which had been replaced with such access in mind?
It is one of the methods accepted for inaccessible joints. 526.3
One option is to put the junctions in back boxes in the wall a few inches above the floor and cover with a blank front plate.
It depends what you mean. It is an explicit regulation (for new 'inaccessible' joints/JBs) in BS7671, so one would be non-compliant with BS7671 if one installed new inaccessible JBs which were not 'MF'.
However, you might simply be making the point that there is no statutory (or other 'mandatory') requirement to comply with BS7671. However, as you know, for the great majority of people, the only way they can demonstrate/claim compliance with Part P is to demonstrate compliance with the current version of BS7671.
Kind Regards, John
Phew what a mine field. Thanks John and all who answered. Main reason is a shoulder problem and spending ages under a ceiling connecting several wires will be very uncomfortable. I need to maybe reconsider the JB method. Thanks again everyone.
The traditional screw terminal type need to be re-tightened after a few hours/days, the MF ones do it automatically.
Then loop at the switch. I have only 3-plated a handful of times in the last year
Since when? I've gone back to such junction boxes I've installed years later and they've been fine. Or are you saying that junction boxes are now becoming a similar fiasco to the terminals on main switches which mysteriously seem to work loose? If so, then perhaps the JB manufacturers should stop trying to re-invent the wheel with new designs which don't work and return to tried and tested designs which do.
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