Metal sockets and additional earths

[HertsDIY]

Hi,

From previous research I know that additional earth wires are advised when metal light switches and sockets are involved and that this is done by adding an extra earth wire from the metal switch/socket plate to the back box in the wall where there is (usually) a screw provided.

Is this any different in the bathroom for my metal shaving socket as I noticed the electrician has connected this new socket without an additional earth to the back box?

Thanks in advance for your thoughts/comments.

 

[ricicle]

It is not considered necessary if the metal box has at least one fixed lug and the cpc is not via conduit or the like glanded into the box.

 

[HertsDIY]

Thanks for response but please translate!!!

 

[ricicle]

If the metal box has one lug (screwhole) which is actually part of the metal box (rather than being a seperate adjustable one which can move to allow for plate levelling) then this is considered adequate to provide an earth path via the plate screws to the box.
This all assumes that the light circuit actually contains an earth (Circuit Protective Conductor)

 

[Chri5]

I'd want a cast iron earth for the f/plate.

In addition to the screw on a fixed lug (which 'joins' the faceplate housing to the back box) run a strapper earth which is a sleeved earth or bit of grn yellow 1.5mm single core between the back box stud and the earth point on the metal faceplate.

Bathrooms, metal plates and 100% earth connection makes sense and it adds all of 2p to the job and takes at least 13 seconds.

 

[CWESPARK]

I'd want a cast iron earth for the f/plate.

In addition to the screw on a fixed lug (which 'joins' the faceplate housing to the back box) run a strapper earth which is a sleeved earth or bit of grn yellow 1.5mm single core between the back box stud and the earth point on the metal faceplate.

Bathrooms, metal plates and 100% earth connection makes sense and it adds all of 2p to the job and takes at least 13 seconds.

Not at my prices it don't!

 

[deafboy]

and of course we are assuming that the cable supplying the shaver has an earth wire?

 

[ban-all-sheds]

In decreasing order of goodness:

1. Cpc to earth terminal of accessory, additional flylead from there to earth terminal of box.
2. Cpc to earth terminal of accessory.
3. Cpc to earth terminal of box, additional flylead from there to earth terminal of accessory.
4. Cpc to earth terminal of box.

 

[JohnW2]

In decreasing order of goodness:

1. Cpc to earth terminal of accessory, additional flylead from there to earth terminal of box.
2. Cpc to earth terminal of accessory.
3. Cpc to earth terminal of box, additional flylead from there to earth terminal of accessory.
4. Cpc to earth terminal of box.

I agree that is a reasonable ordering of 'goodness' but, if I may be so bold, I would suggest that there are variants of (1) and (3) which would theoretically represent an even higher degree of 'goodness' than (1), namely:

• 1a... CPC to earth (or should that be bonding?) terminal of accessory, with CPC then continuing, unbroken, to earth terminal of box.
  3a... CPC to earth terminal of box, with CPC then continuing, unbroken, to earth terminal of accessory.

I don't think there is really anything to choose between (1a) and (3a) but, because they utilise an unbroken CPC, I think this method theoretically deserves an even higher 'goodness' rating than the 'additional (which I take to mean 'separate') flyleads of (1) and (3).

Kind Regards, John.