Earthing existing lighting switches

[SykesIT]

Hi I have an older house with no earth wires in the downstairs switches for the main light. The light itself is earthed but the 2 switches that control it are inset and have no earth.

I want to add an earth (CPC) and RCBO on the circuit so I can use metal back boxes (As I assume plastic are not available to be plastered in a wall) and switches.

I understand that the earth will need to be 4mm earth for safety but can I just send the earth back to the consumer unit which is in the cellar below the floor or do I have to go to the ceiling rose? 

One switch is right behind the earth leading to the ceiling rose (in a void above cellar door) as I believe this was run seperate over 10 years ago, so can I connect in to this with a junction box or is this not allowed.

Thanks

 

[Murdoch]

Having switch drops not earthed and no metal back boxes points at a 1960’s or early 1970’s installation ..... so before you start spending money I would recommend you get the circuit tested properly ......

do you have test kit?

 

[Evans Electric]

You say the ceiling rose is earthed  ,  might be worth checking the switch drop cable to see if theres an earth  snipped off  in the cable . Check that it,s connected at the ceiling rose.    Or presumably  just a twin cable was installed .  Stupid stuff like that  went on a lot back in the day.   

You say you can get back to the cellar so you only need a 1.5mm  Green/yell  back to the board  , not 4mm .  

 

[Spoon]

You say you can get back to the cellar so you only need a 1.5mm  Green/yell  back to the board  , not 4mm .  

Reg 543.1.1 says he has to use 2.5mm or 4.0mm mate..

the cross-sectional area shall be not less than 2.5 mm2 copper equivalent if protection against mechanical damage is provided, and 4 mm" copper equivalent if mechanical protection is not provided (see also Regulation 543.3.1 ).

 

[Spoon]

Hi I have an older house with no earth wires in the downstairs switches for the main light. The light itself is earthed but the 2 switches that control it are inset and have no earth.

I want to add an earth (CPC) and RCBO on the circuit so I can use metal back boxes (As I assume plastic are not available to be plastered in a wall) and switches.

I understand that the earth will need to be 4mm earth for safety but can I just send the earth back to the consumer unit which is in the cellar below the floor or do I have to go to the ceiling rose? 

One switch is right behind the earth leading to the ceiling rose (in a void above cellar door) as I believe this was run seperate over 10 years ago, so can I connect in to this with a junction box or is this not allowed.

Thanks

It sounds like the light fitting is OK as it has an earth going to it.

Just the light switches may not have.

As above, check cable to see if the earth has not just been snipped off.

As a different solution, you could make the switching of the light wireless. Then  you can add switches where you like.  Quinetic apparently do a nice range. 

 

[Sidney]

Are the cables buried in plaster or run in conduit?

 

[Pete10001]

Hi I have an older house with no earth wires in the downstairs switches for the main light. The light itself is earthed but the 2 switches that control it are inset and have no earth.

I want to add an earth (CPC) and RCBO on the circuit so I can use metal back boxes (As I assume plastic are not available to be plastered in a wall) and switches.

I understand that the earth will need to be 4mm earth for safety but can I just send the earth back to the consumer unit which is in the cellar below the floor or do I have to go to the ceiling rose? 

One switch is right behind the earth leading to the ceiling rose (in a void above cellar door) as I believe this was run seperate over 10 years ago, so can I connect in to this with a junction box or is this not allowed.

Thanks

Why 4MM2?

 

[Spoon]

Why 4MM2?

Reg 543.1.1 says he has to use 2.5mm or 4.0mm.

See my post above with a quote from the regs.

 

[Murdoch]

If the op is planning on running a seperate earth, then why not replace the cable to the switch? 

There may be a conduit in the wall too ....