Question.

I have a multi building site. (car showroom and workshops) It has two electrical feeds into the site. one water supply and water meter. one gas supply and gas meter.

However the water supply is fed under ground into all the buildings and so is the gas.

The mains water supply is bonded at the supply to the MET next to it. However there is no further bonding to the water supply where it pops up in the other buildings and the water pipes are copper. So where this occurs the water supply needs bonding in each building.

The workshops are a series of added on buildings all connected to each other, when each extension was added a new electrical sub board has been added, along with a water supply.

My question is can the water supply in each of these extensions be bonded to the MET in the local sub boards or do they require going back to the mains incomers MET.

Bonding (including an earth terminal) should be repeated for each building - so bonding in a remote building should be connected to the earth terminal in the same building - but if the remote buildings are using the main building's earth, then the submain "c.p.c." also needs to be big enough to satisfy the requirements for a main bonding conductor (i.e. based on the supply N (if PME) or main building's earthing conductor (if TN-S)). Alternative would be to have a separate earthing system for a remote building - e.g. to TT it.
- Andy.