Lighting Circuit Nuetrals in Domestic Light Switches | Page 4 | on ElectriciansForums

Discuss Lighting Circuit Nuetrals in Domestic Light Switches in the Domestic Electrician Forum area at ElectriciansForums.net

B

Barrie Patrick

Its been many years since I passed my Apprenticeship and was active on the tools and although a little rusty, (the last training I did was a familiarisation course and an Inspection & Testing Course when the 17th Edition of the IEE Regs replaced the 16th Edition, 1988?) I think I am still a decent Electrician and good Tradesman so can still tell whats right and wrong but as so much has changed in the industry there can always be a little doubt in the back of your mind and I would like a couple of questions confirming?

I recently went to my Neices birthday party at their new house and one of my nephews said the 2 way lighting on the upstairs landing wasn't working and could I have a quick look rather than get myy neices friends, girlfriends brother, who had changed their Consumer Unit and wired up their garage to come again and sort it, I had a look and quickly found it was wrongly connected making 1 switch master to the other so I put it right. My neice was that proud of her new home she showed me round, we went to the garage and alarm bells started to go off, it has 3 lights controlled from a 2 gang light switch by the door, the lighting is wired in white 1.5mm 3 core and earth badly clipped with unevenly spaced clips of varying types and sizes and the switch box is very deep, looks crap but not necesarily unsafe, however there are 4 individual 3 core cables hanging down the wall unclipped and going into the switch box. I took off the cover and in the back were connectors for the 4 nuetrals (black) and 4 earths (Green/Yellow sleeved), the browns were the live feed in, loop to the next room that was built in the back of the garage and the 2 switch wires and the greys had all been cut off, so I took off the switch in the little room and the nuetral was also wired through the switch.

I looked at the Consumer Unit and it looked nicely done but no notices or circuit information given, only the ring main cables for downstairs were to short and the cables had been extended using proper joint boxes fixed to the wall underneath the new CU However no evidance of testing.

My questions are, and I already know the answer:

1) Its not in accordance with the BS 7671 or good practice to wire nuetrals through a switch, unless a double pole switch is used and certainly bad practice to use a connector pushed into the back of the box for the nuetrals and earth?

2) Lighting should be wired using the 3 plate system, no nuetrals at switches?

3) Under the Building regs the work is notifiable and the whole installation should be tested?

Barrie
 
If the OP has used pork pie JB's to connect each down light, then there's no access problem because if they went into the hole for the down light, then they can be easily accessed by the same hole?? I have done this on many occasions. I would never put them under floor boards though. And Wago's are a good idea but they have only been out for 5 maybe 10 years!! How can any one guarantee they are MF??? They haven't been tested long enough.

Jay

If they have no strain relief for the cables then they need to be fixed though. Daz
 
If the JB is resting on the under side of the ceiling, about 6 inch away from the down light, wheres the strain?? So you pull your down light down and the JB is there. Easy access, no strain??!!

The strain relief in junction boxes is there so that when the junction box and cables are moved around, the terminations are not put under stress, especially where the relatively non-flexible t&e is used. Daz
 
The strain relief in junction boxes is there so that when the junction box and cables are moved around, the terminations are not put under stress, especially where the relatively non-flexible t&e is used. Daz

I know what you are trying to say but i just cant see how a downlight is gonna move around when its in a ceiling. Jay
 
Down-lights have been installed without using strain relief or MF JB's for years without problems surely.

So have lots of things, doesn't make it right though. And don't have to be MF when accessible, but still should have strain relief.

The IEE Wiring Regulations state that terminals shall not be subject to undue stress,
i.e. taking weight of cables or fittings.
Currently a high proportion of Junction Boxes are installed behind Downlighters or
decorative light fittings, where moving the Junction Box in to position after wiring
could cause stress on the terminations.
 
It's more the juggling around and moving things around when the boxes are pushed up into the ceiling though. Daz

Is that why sockets, switches and cooker control units all have built-in cable restraints? Lots of juggling around especially with 6 & 10 mm cables, and quite likely that a "Part P" decorator will pull them free to tuck the wallpaper into the box or paint round them.

Maybe if the JB is in an accessible place where someone may trip over it, such as a loft then I agree the terminations could conceivably end up under some undue strain. I feel this is another of those regs designed to sell more expensive new products.

Having said all that, I usually use wago boxes or hager MF JBs as they're quicker to wire.
 
It's more the juggling around and moving things around when the boxes are pushed up into the ceiling though. Daz


ok, so what about the terminal block on top of the down light. Is that classed as inaccessible.
or If they have a transformer. Both of these would have the same problem as you described with the jb.
Jay
 
ok, so what about the terminal block on top of the down light. Is that classed as inaccessible.
or If they have a transformer. Both of these would have the same problem as you described with the jb.
Jay

Possibly so, but the regs state strain relief on JBs that are not fixed, as above. Daz
 
So have lots of things, doesn't make it right though. And don't have to be MF when accessible, but still should have strain relief.

The IEE Wiring Regulations state that terminals shall not be subject to undue stress,
i.e. taking weight of cables or fittings.
Currently a high proportion of Junction Boxes are installed behind Downlighters or
decorative light fittings, where moving the Junction Box in to position after wiring
could cause stress on the terminations.

Personally i have always used Hager J501 junction boxes for down-lights.

Did any of the older style Jb's have strain relief? All the ones i have seen on the job generally don't have it.
 
Quite often, people just used to use the 'normal' brown jbs and leave them dangling under floorboard and god-knows where :)
 
Ok, so you fix the jb to the joist. The cable that comes from it to the down light will still move around when, as you say, you are messing with the light. Not having it fixed would actually be better for the terminations.
bnin
 

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