Lighting circuit not working after earth removed.

[Bosworthbear]

ok. I tried to fit dimmer switch, realised that I needed to earth it to the metal case. Unscrewed earth in plastic box, decided that I needed a seperate earth wire. Replaced everything and didn't fit dimmer. Light still works. However I now find that the other (newer) lighting circuit for the upstairs lights no longer work and all of the lights in the upstairs extention have ceased to work.

My fusebox has a sticker on saying that if an earth is not working properly then it will trip, but the testing button shows no problems trips and then works again on all lights bar the extention circuit. Where do I go from here please???

 

[luminaire]

What do you mean by "unscrewed earth in plastic Box"? What plastic box?
Do you mean the earth terminal on the back box presuming that to be a dry lining box. Because removing and replacing that back again should not affect anything.
So either you've done something else or a fault has suddenly occurred on the newer lighting circuit.

 

[TicklyT]

How many wires have you got at the switch?
With loop at switch wiring, transposing the 'loop out' wire, would mean everything beyond the switch would then be controlled by that switch.

Has somebody been very naughty, and used the earth terminal in the plastic box to connect the neutrals

 

[Bosworthbear]

There are three neutrals twisted together attached to back plate/plastic box. Three other wires, 2 of which are connected to"front" switch.

 

[jj4091]

It does not sound as though you have an earth wire in the switch box, which means that you cannot safely fit a metal faced dimmer without running in a separate earth wire from another source in the lighting circuit. It would probably be a lot easier to fit a plastic dimmer & connect it as the old one was.

 

[ban-all-sheds]

There are three neutrals twisted together attached to back plate/plastic box. Three other wires, 2 of which are connected to"front" switch.

This is very unlikely.

AFAIK, the practice of looping through switches, which is the only way you'd get neutrals there, is too recent for there not to be an earth. Conversely, unearthed lighting circuits date from too long ago for the circuit to have been looped through the switches, they'd have been looped through the ceiling roses and just live/switched lives dropped down to the switches.

 

[daytona]

well,sounds like you did something in the switch .can you upload a photo?


first of all you said you had an earth attached to the backbox,then 3 neutrals,so somethings going on.

cant believe im still here,has anyone seen my apprentice?

 

[TicklyT]

With three cables at the switch, it does sound like loop at switch, in which case, there would normally be a total of 9 wires.

3 X CPCs (earths) in terminal attatched to back box.
3 X Neutrals commoned together in a choc bloc connector
Live Loop In
Live Loop Out
Switched Live

Normally, there would be three wires connected to the switch. loop in & loop out together on one terminal, and switched live on another.

It is not unknown for a wire to break when an accessory is disturbed if the core was nicked when the end was stripped, or if the core was cut by the terminal screw, leaving little clue as to where it was connected.
Were there any short stub ends of wire left in the terminals of the switch you removed?

Before connecting any other wires, be sure you know exactly where the wire goes