Metal - clad buildings and the confused forum member.

I have had conversations in the past separately with a couple of DNO managers and an assessor who visited a large brick and stone building I was working on where commercial office space was being converted to flats, there are two three phase supplies serving the flats and an estate agents office with shared metallic pipework, but the gas meters are in another part of the building with another five commercial units each with a single phase intake.


They laughed because I made a redundant three phase SWA cable into a main earth conductor using all four 16 mm conductors and the armour in addition to using two more 25 mm conductors and the armour of a SWA cable reutilised to supply a flat, then bonded the shared pipework to both of them. There was one point in an old gents toilet on a landing with metallic pipework running through it that seemed to be the point of most concern, it didn’t look much, but if you figure out the runs of the pipes and the location of the intakes cutting the pipework could have been really dodgy until a substantial section of it was replaced with plastic.


UK plumbers, gas fitters and others rarely bother to use temporary bonding kits when cutting sections of metal pipework out, you often see the kits hanging up in their vans, but that’s where they stay. They are also not averse to ripping off the earthing and bonding, as it “doesn’t really do anything”.


Yet I have seen sparks from disconnected pipes, bonding and earthing which don’t half make you stop and think.


Edit- I could never ascertain that all the intakes within that building were from the same substation and transformer.

I have had conversations in the past separately with a couple of DNO managers and an assessor who visited a large brick and stone building I was working on where commercial office space was being converted to flats, there are two three phase supplies serving the flats and an estate agents office with shared metallic pipework, but the gas meters are in another part of the building with another five commercial units each with a single phase intake.


They laughed because I made a redundant three phase SWA cable into a main earth conductor using all four 16 mm conductors and the armour in addition to using two more 25 mm conductors and the armour of a SWA cable reutilised to supply a flat, then bonded the shared pipework to both of them. There was one point in an old gents toilet on a landing with metallic pipework running through it that seemed to be the point of most concern, it didn’t look much, but if you figure out the runs of the pipes and the location of the intakes cutting the pipework could have been really dodgy until a substantial section of it was replaced with plastic.


UK plumbers, gas fitters and others rarely bother to use temporary bonding kits when cutting sections of metal pipework out, you often see the kits hanging up in their vans, but that’s where they stay. They are also not averse to ripping off the earthing and bonding, as it “doesn’t really do anything”.


Yet I have seen sparks from disconnected pipes, bonding and earthing which don’t half make you stop and think.


Edit- I could never ascertain that all the intakes within that building were from the same substation and transformer.