J
Jim The Fish
Right I am a little confused regarding main and supplementary bonding?
Hers the scenario, I am wiring two outbuildings which are being used to rehabilitate dogs with muscular/skeletal issuses.
In one building there is a swimming pool, shower room and utility room. In the other is an office, kitchen and kennel area.
The buildings are supplied via a three phase TT system and all circuits rcd protected.
The incoming water and gas are supplied with plastic pipe with switches to copper just above floor level. The heating and water pipes drop out the boiler in copper switch to plastic run into the floor and pop up to the rads with a short piece of copper.
Am I right in thinking that as the supply pipes are plastic I need not install a main bond at the intakes? also if the rads are not introducing an earth potential they effectively do not count as extraneous parts and will not require supplementary bonding?
I am also a little confused on how to test if an item requires bonding, I seem to recall at college performing a continuity test between exposed and extraneous parts and checking this result falls beneath the 1667ohm limit to give a touch voltage of less than 50v. Was this test just used to prove the effectiveness of supplementary bonding or to prove the requirement for bonding?
If I want to prove there is no earth potential introduced by an extraneous part can I do an IR test between said part and the MET, if so what minimum reading should I look for?
Are there any other considerations to take to determine the requirement for supplementary/main bonding?
A lot of questions I know but please pardon my ignorance on these matters. I have spent all of my electrical working life on the motorways and I have only just started to take on domestic works so I am not used having to make these decisions as all our equipment cabinets have the same old earthing/ bonding arrangements.
Many thanks in advance for any help given it is all greatly appreciated.
Ta
Hers the scenario, I am wiring two outbuildings which are being used to rehabilitate dogs with muscular/skeletal issuses.
In one building there is a swimming pool, shower room and utility room. In the other is an office, kitchen and kennel area.
The buildings are supplied via a three phase TT system and all circuits rcd protected.
The incoming water and gas are supplied with plastic pipe with switches to copper just above floor level. The heating and water pipes drop out the boiler in copper switch to plastic run into the floor and pop up to the rads with a short piece of copper.
Am I right in thinking that as the supply pipes are plastic I need not install a main bond at the intakes? also if the rads are not introducing an earth potential they effectively do not count as extraneous parts and will not require supplementary bonding?
I am also a little confused on how to test if an item requires bonding, I seem to recall at college performing a continuity test between exposed and extraneous parts and checking this result falls beneath the 1667ohm limit to give a touch voltage of less than 50v. Was this test just used to prove the effectiveness of supplementary bonding or to prove the requirement for bonding?
If I want to prove there is no earth potential introduced by an extraneous part can I do an IR test between said part and the MET, if so what minimum reading should I look for?
Are there any other considerations to take to determine the requirement for supplementary/main bonding?
A lot of questions I know but please pardon my ignorance on these matters. I have spent all of my electrical working life on the motorways and I have only just started to take on domestic works so I am not used having to make these decisions as all our equipment cabinets have the same old earthing/ bonding arrangements.
Many thanks in advance for any help given it is all greatly appreciated.
Ta
