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

 

[DPG]

I,m sure that junction box will fine and as long as all terminals are nice and tight the junction box if fixed and the cable cliped it will be good for 100 years or more !!!

Not convinced - I've seen quite a few loose terminals. Especially if there's also no strain relief on the cables. Daz

 

[Jay Sparks]

Another good reason why neutrals are connected in the switch back box's, is with the advent of the RCD. When testing your Zs on No trip, as you need to connect to the neutral as well, it's a lot easier to do at the switch, than the light fitting on ladders.

Jay

 

[Flanders]

Not convinced - I've seen quite a few loose terminals. Especially if there's also no strain relief on the cables. Daz

yes i have tloo but always belieave if its install propley in the first place then it will last for years .

 

[7029 dave]

yes i have tloo but always belieave if its install propley in the first place then it will last for years .

I agree with you, having said that any joint anywhere is going to be an fault liability.

 

[Marvo]

The reason that neutrals in switches is no longer considered bad practice is that nobody has ever come up with a valid reason as to why it is bad practice.
The arguments are that the neutral is not necessary in a switch box. That argument ignores the fact that a permanent live is not necessary at a 3 plate light point.
Another argument is that a switch box is not a suitable enclosure for joints,which ignores the fact that neither is a light fitting.

Neutrals through switch boxes is the normal way of doing things where I am and this post pretty much sums up my sentiments about it. It's something that some of the older guys feel strongly about but I've never heard a convincing argument against it.

 

[Barrie Patrick]

Have to say Thank You to everyone whose replied and I'm sorry if the topic of neutrals in light switches had previously been done to death on here but I've actually found it very useful to hear what some of the Younger guys on here actually do when installing and what they think. I think if I ever do any wiring again I'll think about running the neutral through the switch................... then Not do it LOL

One reason I remember the tutor giving us at Tech for not taking a neutral through a switch was it increases the chance of electric shock because there is a return path at the switch, I always thought this a little lame as there is already an earth there as a return path, that switched sockets outlets, spur units and double pole switches had a neutral and earth with a switch and it was deemed ok so like others I dont really have a valid argument for not doing it :-(

However, I'm afraid I will probably stick with what I know but now I wont criticise other Sparkies who do run neutrals through switches and if ever stuck I'll do it without that guilty feeling I would have once had LOL

Barrie

 

[PEG]

Welcome,Barrie, and may i take this opportunity to applaud an action,that three pages on,everybody has overlooked...

That is,that you got yer tools out,at your nieces party ...a man after my own heart...

 

[Paulgwat]

I would expect to see Neutrals being brought into light switch back boxes being something that will get more common with the rise in popularity of home automation systems as most of the lower cost systems such as Zwave and Fibaro etc need a neutral to work.

If doing a rewire I personally would bring a neutral to each light switch as a minimum, if not all of the Nautrals for that circuit.

My understanding was that the UK was the odd one out and that in most other European countries you would expect to see Neutrals in a light switch back box as a normality.

Paul

 

[M-Ty]

One reason I remember the tutor giving us at Tech for not taking a neutral through a switch was it increases the chance of electric shock because there is a return path at the switch, I always thought this a little lame as there is already an earth there as a return path <SNIP>
Barrie

You're right: It sounds like he was more familiar with the 13th Edition with its un-earthed lighting circuits, if non-conducting floors, and/or metal fittings (now luminaires) placed out of reach.

 

[hightower]

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. ...

 

[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.

 

[IzzyS]

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