Gas bond in detached garage ?

Hi Guys.

I carried out an EICR earlier and am a little unsure of the bonding setup.  House built in 1982. Original wiring which is ok. 16mm tails/6mm earth. 6mm bonding conductors. 60 amp main fuse.

The gas meter is in the detached garage. About 2 meters from house. There is a 6mm gas bond in there at the gas meter that is clearly under sized as it has been taken from the 2.5mm supply cable for the garage power.

The gas pipe from the meter goes through a 4inch duct and pops up in the kitchen below the units next to the water pipe. Both are bonded there in 6mm. This area backs onto the garage so in reality 2 or 3 meters away if that is relevant. 

My question is is the bond by the gas meter actually required as it is outside anyway or will it potentially need upgrading.

My gut reaction is it is fine as it is. There is no water in the garage.

The supply pipe to the gas meter drops into the concrete floor and as far as I can chip the floor away looks steel, although I am only seeing threading nut connections before it is buried so may well be plastic.

Any guidance would be appreciated

Thanks.  Gary

Parents
  • Yes best practice guide 4 Says if it is less than 6mm it should be coded as a C2. So implying an existing 6mm is OK. 16mm tails with a 6mm earth and 6mm bonding on a 60A fuse used to be pretty standard around here when I started in 1984.

    That doesn't solve the garage problem here mind :( 

    Agreed for PME.

  • The copper pipe will be about 30mm2 if it is 15mm copper, (Pi * diameter * 0.75mm)  and more like 55mm2 if it is  the more common 22mm OD, and assuming it is gas safety and use regs compliant, it will be soldered if there is any joint at all in the duct. You could poke in a bit of wire parallel to it in the fat pipe, but electrically whatever you do, it is the gas pipe that will always do the heavy lifting in terms of conducting as a parallel path.

    Its not dangerous, but it may well not meet the letter of current regs.
    Mike

Reply
  • The copper pipe will be about 30mm2 if it is 15mm copper, (Pi * diameter * 0.75mm)  and more like 55mm2 if it is  the more common 22mm OD, and assuming it is gas safety and use regs compliant, it will be soldered if there is any joint at all in the duct. You could poke in a bit of wire parallel to it in the fat pipe, but electrically whatever you do, it is the gas pipe that will always do the heavy lifting in terms of conducting as a parallel path.

    Its not dangerous, but it may well not meet the letter of current regs.
    Mike

Children
  • I agree. The other issue I have is that they have asked me to upgrade the consumer unit as it still has the original 3036 fuses and no RCD protection anywhere. So I will have an EIC that needs to comply even if there is a bit of 'wiggle room' on an EICR. Upgrading the bonding is pretty much impossible without massive disruption and taking part of the kitchen out. The CU is in the middle of the main house pretty much which is not small. Disappointed

    Real world issues trying to make things safer and I might walk away from upgrading it. 

    Gary