Main Bonding !!!!!!!!!!!!!!!!!!!!!!!!

Toneyz · Jan 4, 2018

Had the electrical consultants out to site today to look around and he wants us to bond the steel girders on each floor around the lift, this is just a isolated piece of metal supporting the concrete floor where they cut a hole for lift.Also, the gas is a new supply (wall surface meter box) screwed iron on outside then changes to copper approx direct to combi boiler a meter. When we bond the water this is a copper pipe teeing of to feed toilet rooms etc.ending up with this boiler supply.All pipes are common on to the plate under the boiler- what are your thoughts.

Pete999 · Jan 4, 2018

anthonybragg said:
Had the electrical consultants out to site today to look around and he wants us to bond the steel girders on each floor around the lift, this is just a isolated piece of metal supporting the concrete floor where they cut a hole for lift.Also, the gas is a new supply (wall surface meter box) screwed iron on outside then changes to copper approx direct to combi boiler a meter. When we bond the water this is a copper pipe teeing of to feed toilet rooms etc.ending up with this boiler supply.All pipes are common on to the plate under the boiler- what are your thoughts.

Hope you get a VO for the extra work Ant, cant really see why this wasn't picked up at the design stage.
What were his reasons for this at this late stage, any testing been done?, although as the structural steel work is a service that requires a main bond, perhaps an oversight on someones part, does the building you are involved in have a lightning conductor installe as this will require bonding as well.

westward10 · Jan 4, 2018

If it is a "floating" piece of metalwork not likely to introduce potential I see no point.

Toneyz · Jan 4, 2018

Pete999 said:
Hope you get a VO for the extra work Ant, cant really see why this wasn't picked up at the design stage

We have not got to that stage yet but the steel around lift openings are not in contact with the ground it may come into contact with the earth metalwork of the PLATFORM type lift and the internal gas pipework
in copper is only 600/700mm from wall to metal joining plate which has the bonded water pipe. p.s. Pete this is what your council tax is being spent on.

Toneyz · Jan 4, 2018

westward10 said:
If it is a "floating" piece of metalwork not likely to introduce potential I see no point.

This was my thinking.

Pete999 · Jan 4, 2018

anthonybragg said:
This was my thinking.

That's why I asked if it has been tested, how sure are you that the metalwork will not introduce a PD into the building? maybe just bond it and collect the VO value.

Strima · Jan 4, 2018

Has the isolated metal been tested back to the MET so see if extraneous? Would this also need testing to the lift car? i.e. is there a risk of potential difference when the lift car is at each floor?

Pete999 · Jan 4, 2018

Strima said:
Has the isolated metal been tested back to the MET so see if extraneous? Would this also need testing to the lift car? i.e. is there a risk of potential difference when the lift car is at each floor?

Good point