Lighting Circuit Nuetrals in Domestic Light Switches

[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

 

[Midwest]

BS 7671, 526.3. Makes a start.

 

[hightower]

Must have been here in my 2365 textbook.

 

[Andy78]

On the subject of accessibility I'm sure I've seen somewhere that a hatch in the floorboards is acceptable for screw type junction boxes. Will try and remember where I saw that. ...

It's debatable really whether or not a hatch is considered accessible or not. I personally only fit MF connections under floors. I may make an exception for a marked board in a central heating cupboard or understairs cupboard that has exposed boards as it is easily spotted and accessed.
A hatch under a floor is only accessible after all the furniture has been moved and the carpet taken up. Not my idea of accessible. And it's only accessible in that manner as long as no laminate/tiles/lino is put down over it.

 

[richy3333]

Hi Again Midwest,

I have installed some down lighting fited with cold running LED's in my kitchen and utility room and downstairs toilet using the existing 3 plate lighting system, I just used a junction box to create the lighting point in each room then looped the switched live and perminant neutral and earth (cpc) from light to light, it all went in very nicely.............. Please dont tell me there is now a Reg that says I should have switched the neutral LOL

Barrie

hope that JB was a MF one

 

[Jay Sparks]

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

 

[DPG]

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

 

[Jay Sparks]

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??!!

 

[DPG]

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

 

[Jay Sparks]

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

 

[DPG]

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

It's more the juggling around and moving things around when the boxes are pushed up into the ceiling though. Daz

 

[Simonslimline]

Down-lights have been installed without using strain relief or MF JB's for years without problems surely.

 

[DPG]

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.

 

[Old Tiler 19727]

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.

 

[Jay Sparks]

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

 

[DPG]

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

 

[Simonslimline]

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.

 

[DPG]

Quite often, people just used to use the 'normal' brown jbs and leave them dangling under floorboard and god-knows where

 

[7029 dave]

Quite often, people just used to use the 'normal' brown jbs and leave them dangling under floorboard and god-knows where

Always screwed mine down to the joist, Dave tight as good as any MF jb.

 

[DPG]

Always screwed mine down to the joist, Dave tight as good as any MF jb.

Agree. Done up nice and tight and the jb screwed to the joist is good for years. Daz

 

[Jay Sparks]

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

 

[DPG]

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

No, use a JB with strain relief for both the incoming and outgoing cables. Doesn't have to be fixed then and no dangr of cables working loose. Daz

 

[Andy78]

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

The reason you would fix the JB to a surface is so that you could add external strain relief in the form of cable clips.

 

[Jay Sparks]

But how can you clip the cable supplying the down light. LiKe i said, there is very little chance of movement on the terminations if the job is done right. How often do you need to take the down light down.

 

[ipf]

Heavens above! We're 'outlawing' decently installed, unfixed brown jb's, above recessed lights when you look at the state of some of the items we come across. Let's get real.....

 

[DPG]

To be fair, I don't think anyone is outlawing decently installed traditional round junction boxes! Daz

 

[Andy78]

All that's being stated is what's currently compliant and what's not.
This may or may not have a bearing on what makes sense or has a bearing on real life issues in installs.

 

[ipf]

To be fair, I don't think anyone is outlawing decently installed traditional round junction boxes! Daz

'outlawing'....being used as a term of phrase, not literally......but almost as good as, and I'm sure some would take it that way.
It's just making mountains out of molehills, again.

 

[Midwest]

Common chaps you can't argue DPG's point. Brown circular JB's have been around donkeys years. They were designed to be fixed to a surface, joist perhaps, and the cables entering them were clipped to said joist. No strain likely on terminals. That was how I was taught as an apprentice. Over the cause of time, these JB's have been used in a way they weren't designed for, done it myself.
I very rarely use them now, preferring MF boxes. Cables entering fittings (sockets etc) are normally clipped, in trunking etc or covered over with plaster. Is someone takes off the faceplate (Mr Decorator), well you can't cover all bases, and is another matter entirely. All of the of the downliight I've fitted have a cable strain clamp. Not the case for all other luminaires I grant you.