Earth Wire to Metal Switch ?

[self builder 123]

Hi

In our house we have MK modular switch plates fitted. The switch module is snap mounted in a grid. The grid itself is earthed to the metal back box.

Now the metal cover plate is simply attached to the grid using 2 screws.

So the metal cover plates are earthed via these screws ?

I take it that this is compliant / safe ?

Many thanks.

 

[wingcoax]

If there is no terminal on the back of the plate, then yes it is ok.

 

[self builder 123]

So if for any reason the face plate became live then it would connect to earth via the screw fixings.

I take it that this is safe and acceptable to our BCO ?

 

[sparkybird]

I think you'll find that there is an earth terminal on the MK grids. Is it going to be that difficult to run a bit of 1.5 earth to it from the back box?

SB

 

[Spark123]

No, you always need to earth the face plate where there is an earth terminal provided.

 

[self builder 123]

I understand that the grid mounting bracket is earthed to the metal back box, which itself is earthed.

However the metal face plate relies on the screws to earth it to the grid mounting bracket.

This just seems odd ?

 

[self builder 123]

Hi Spark 123

I understand that the face plate will be earthed through the metal screws - I take it that this is safe and acceptable ?

 

[Spark123]

No, it isn't imo acceptable as what happens if someone loosens the screws off?
Similar concept to sockets, the back box can be earthed through the screws but you cannot earth the socket front from the back box via the screws.
In either case I tend to put the link in and earth both the accessory and the back box as belt and braces.

 

[Johnmelad502]

Hi Spark 123

I understand that the face plate will be earthed through the metal screws - I take it that this is safe and acceptable ?

Fit the earth wire to the back of the switch as a minimum. I personally would then run an earth from the switch to the backbox as well.

 

[self builder 123]

Hi

back box is earthed.

grid plate is earthed to back box via earthing wire.

face plate screws onto the grid plate - there is no earthing tag on the face plate.

Parts came from MK Electric.

So as there is no earthing tag there is no requirement to earth ?

 

[Spark123]

If the grid is earthed then that is fine, I was thinking you were meaning earthing the grid via the back box screws.