What does this mark mean?

[RegB]

Hi, I wonder if anyone can clarify this. There's an electrical water heating appliance in the loo. As you can see in the picture in the link below there's an earth symbol above a screw next to the power cable. Presumably the appliance is earthed through the main cable so does anyone know what this extra earth is for? Supplemental bonding perhaps?
(Link below)

Earth pic

• RegB
• 5 Aug 2009
• 1

Many thanks for any ideas.
Reg

 

[JohnD]

It's an earth stud

It will be for cross-bonding to other pipes and circuits especially if in a bathroom, or the the Manufacturer's Instructions require it.

Note that Supplementary Bonding in a bathroom has to be 4mm cable, so the cable in the flex will not be big enough.


If it is in a room which does not contain a bath, shower, etc then you are not required to Supplementary Bond.

 

[RegB]

Fantastic. Thanks for the info John. All the best, Reg.

 

[Lectrician]

Note that Supplementary Bonding in a bathroom has to be 4mm cable, so the cable in the flex will not be big enough.

Positive

 

[kai]

Correct me if I am wrong.

I thought that the Supplementary bonding can be less than the 4mm, provided that the earth core is an integral part of the supply flex to the heater, AND it is wired through a fuse-connection unit, NOT a socket outlet.

 

[RF Lighting]

 

[JohnD]