Missing neutral...

[Mike Blair]

got a call and they said they had a 2 way switch and it stopped working.. after they changed some lights and sockets. The switches them selfs where both trying to switch one light i looked inside and seen the neutral in earth sleeving... but No actual earth was connected "metal faced socket after some tests found out one cable coming in is a switch wire for the first light and the other cable coming from the second cable is live and neutral...


all fixed and corrected now but can someone explain to me...How the hell did they have it working in the first place??

 

[uksparks]

You have three conductors there that could be connected, two browns and a blue, I am sure this would have worked fine.

The neutral is possibly sleeved in green and yellow as its a conductor that is not being used and they have done the sensible thing and earth it which is why you are supposed to do and not just chop it off. I can see an earth there too.

The front faceplate if metal should have a tag to join on to, which you should, but if its screwed into the back box, it will make continuity anyway, so not as bad as it sounds.

 

[Mike Blair]

sorry for the bodgy diagram but this is what it was wired like

 

[uksparks]

Just a thought, but I'd be inclined to think a jumper has been removed.

 

[uksparks]

My thinking is that you have a brown and blue coming in the back, the brown is permanent live and the blue is the switched live going back to a fitting, and the other brown wire, I would suspect this is just a switched live that would be connected to L1 or L2 on one of the switches, and a jumper from the other brown which should be in COM to the COM on that switch maybe.

Don't forget to sleeve the blue with some brown.

 

[Mike Blair]

the neutral in the switch isn't to the supply that's the return neutral so them 2 lights need a return path you get me?

 

[uksparks]

Have you actually put a meter between any of them to see which you have voltage on?

 

[Mike Blair]

yes i found out what was a switch wire and what was not. this diagram make more sense on what i had?

 

[uksparks]

If you say it's like it is, there's no way it could work as you don't have a permanent live at the switch.

 

[Mike Blair]

that's what i said when i went in. one light "the one light on its own" was switching and the other 2 did not turn on. but thay said before the builders came in and did the work. the lights worked on a two way switch but i really cant see how it worked? heads baffled

 

[uksparks]

I think I'd need to be there to see it to be able to say what's wrong.

 

[Mike Blair]

another image

 

[uksparks]

I'd try connect the two Browns to the other side of the switch, so you have the blue in L1 on one side, and the jumper between the commons, and a brown in one of the con I s with the jumper and the other brown in L1 on the other switch, you may have to swap the Browns if it doesn't work one way, try them the other way, what you need is the permanent live in the common with the jumper.

 

[egg67]

Think he fixed it, just wants to know why it was working before builders changed the fitting with that wiring, but unless we can see the wiring before the builder f:cked it up we will never know
But at lest Mike fixed it and left it nice and safe

 

[Mike Blair]

i fixed it not the best method...but its safe and works and didn't kill the client with a bill I feel bad when it happens to people. they pay alot of money for something and no one tests the lecky..so once all the floors in and tiles are on....then there's a problem and it all has to come off due to a idiot

 

[egg67]

It's what happens a lot in our trade, builder kitchen fitter plumber think they know what they are doing, after all it's just a light switch or a plug, do it then self get it all wrong ring us up then think we can fix it without ripping out all the nice work they have just finished . If only they had got us in at the begging

 

[Richard Burns]

I take it that there is no RCD protection and they were using the earth as the neutral return. Dangerous and foolish.

 

[Dave OCD]

And what about the seemingly jagged rough hole in the rear cable entry ?? Maybe a 20mm knockout wasn't obvious enough for them ? :smile5:

 

[Mike Blair]

very dodgy. everything is rcd protected but the lighting.. its been sorted now had to take a earth and neutral from the same circuit and lucky enough there was a light fitting in a cuboard roughly 5 meters away also extended...EVERY SINGLE CUT EARTH IN EVERY SINGLE SOCKET AND SWITCH Dont get why people have the need to cut away the earth cable.

Btw random question... in a bathroom everything has to be rcd protected. these old boards that have everything BUT lighting on the rcd would you find it best to put a rcd spur for the bathroom lighting?

 

[spanishash]

very dodgy. everything is rcd protected but the lighting.. its been sorted now had to take a earth and neutral from the same circuit and lucky enough there was a light fitting in a cuboard roughly 5 meters away also extended...EVERY SINGLE CUT EARTH IN EVERY SINGLE SOCKET AND SWITCH Dont get why people have the need to cut away the earth cable.

Btw random question... in a bathroom everything has to be rcd protected. these old boards that have everything BUT lighting on the rcd would you find it best to put a rcd spur for the bathroom lighting?

Could you not just replace the lighting mcb for a corresponding rcbo? This would then make all switch drops on the same circuit 'up-to-date' concealed in walls/partitions, as well as providing protection to the bathroom.

 

[Mike Blair]

ah yes did not think of that for some silly reason "durp moment" but. what if the board was on rewireables 3036 fuse do they do rcbos for them?

 

[Dave OCD]

No Mike, you'd be looking at a new CU if that was the case, IMO always worthwhile where rewirables are still in use.

 

[shanky887614]

No Mike, you'd be looking at a new CU if that was the case, IMO always worthwhile where rewirables are still in use.

especially as most 3036 boards have about 4/5 cables in each fuse going god nows where

 

[derbylad]

that's what i said when i went in. one light "the one light on its own" was switching and the other 2 did not turn on. but thay said before the builders came in and did the work. the lights worked on a two way switch but i really cant see how it worked? heads baffled

one of the first things i learned was dont believe what they tell you automatically,for instance if the switch only worked on 1 light in the first place then you have now been conned into rewiring the other lights for free.! Get your tester out and then find what's what

 

[Dave OCD]

especially as most 3036 boards have about 4/5 cables in each fuse going god nows where

I did a CU change today just like that, what was crammed into a 6 way brown Wylex is now 9 circuits. Bloody nuisance finding out exactly what goes where sometimes though. :smile5: