Earth Bonding

CMairiD · May 6, 2011

We are getting ready to take over some new builds, so went out today to do an inspection of the gas installations.

The only thing that stood out was the fact that the earth bonding is outside of the sunken meter boxes. Spoke to a sparky mate that says sparkies are quite happy to bond outside of the box as long as it's an 'outdoor grade' clamp and that BS 7671 gives them ability to do so.

Of course our BS 6891 on low pressure pipework requires the bonding to be inside the building or inside the meter box. The only reason I picked this up was because I know what will happen. If the service engineers don't pick it up at annual service, then the auditors will pick up their paperwork for missed defects.

So have you guys run into this before and if so, how did you resolve it?

villa_tom · May 6, 2011

I have seen this loads on new builds where I used to work, we just left as was and noted it on the paperwork. I suppose you could class it as NTCS if you wanted. I was just told that aslong as its within 600mm and not after the first tee then it was fine, although I would note it down on my paperwork

stevetheplumber · May 7, 2011

ive never heard it has to be in the box just in the first 600mm

SafeGasInstall · May 7, 2011

600 mm before the first T for me too,or as it enters the building first visual point will do

tamz · May 7, 2011

It can now be anywhere before the first tee.

This is the problem where different trades and different BS intersect.
From 6891
"For meters in outside meter boxes/compartments, the bonding connection should be preferably inside the building and as near as practicable to the point of entry of the installation pipework into the building."

The problem with inside the building, especially up here where 90% of houses have a solum is the next idiot to come along gives it an NCS as they can't see a bond.

It is not an issue if they use the correct clamps.

Reg Man · May 7, 2011

This has always been a pain to interpret. BS6400 say's within 600mm of the meter outlet. BS7671 says at the point of entry into the building. So the meters a little remote from the building; am i going to run metre's of earthing cable to get 600mm from the meter? No I will put it at point of entry into the building. What is it there for in the first place? protection against shock within the building not outside?