Discuss Bonding - CU or Main Incoming Fuse in the UK Electrical Forum area at ElectriciansForums.net
There are some videos/articles that suggest that distances between the MET and the point of entry of Gas and Water then the Main bonding conductor should be increased to 16mm2, this is a suggestion from people more in tune with this subject than myself, just passing on some information I have heard and seen.I'm aware that a 10mm earth cable needs to run to the incoming water and gas supply but I was wondering if someone could tell me whether this should be from the consumer unit, the main incoming fuse, or both? TIA
For your information and assimilation.There are some videos/articles that suggest that distances between the MET and the point of entry of Gas and Water then the Main bonding conductor should be increased to 16mm2, this is a suggestion from people more in tune with this subject than myself, just passing on some information I have heard and seen.
They are incorrect. Nowhere does BS7671 state or in any way imply that there is a 0.05 Ohm limit to a main protective bonding conductor. This measurement is intended to prove that the connection between the main protective bonding conductor and the extraneous-conductive-part is effectively made. It has absolutely nothing to do with conductor resistance.There are some videos/articles that suggest that distances between the MET and the point of entry of Gas and Water then the Main bonding conductor should be increased to 16mm2
I would overlook it too and instead fit one which reads "Safety Electrical Connection Do Not Remove" ;-)If the MET is not in the CU or main switchgear then a 'Safety Electrical Earth Do Not Remove' label is required. This is often overlooked
Funny you should bring this up did the 18th Ed update yesterday and the tutor mentioned this figure and I asked where it was stated in the Regs which drew a blank look.They are incorrect. Nowhere does BS7671 state or in any way imply that there is a 0.05 Ohm limit to a main protective bonding conductor. This measurement is intended to prove that the connection between the main protective bonding conductor and the extraneous-conductive-part is effectively made. It has absolutely nothing to do with conductor resistance.
Nitpicker…..I would overlook it too and instead fit one which reads "Safety Electrical Connection Do Not Remove" ;-)
Not that I am aware of.Shouldn't it also be labelled as the MET if external to the CU too ?
Funny you should bring this up did the 18th Ed update yesterday and the tutor mentioned this figure and I asked where it was stated in the Regs which drew a blank look.
So sick of hearing this rubbish especially from the apprentices we have at our company being taught false information from tutorsThey are incorrect. Nowhere does BS7671 state or in any way imply that there is a 0.05 Ohm limit to a main protective bonding conductor. This measurement is intended to prove that the connection between the main protective bonding conductor and the extraneous-conductive-part is effectively made. It has absolutely nothing to do with conductor resistance.
There is a calculation in the book based on the size of the largest protective device for bonding, I can't for the life of me remember where it is. I'll have a look for it later.
There is a calculation in the book based on the size of the largest protective device for bonding, I can't for the life of me remember where it is. I'll have a look for it later.
It’s not the adiabatic. This is specifically for bonding conductors not CPCs.Adiabatic equation. If it's TN-S, 10mm may very likely be larger than what is required.
Yeah, 544.1.1It’s not the adiabatic. This is specifically for bonding conductors not CPCs.
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