AJJewsbury:
Humm - that supply looks suspiciously like it might be CNE to the head (alternatively it might be split-con with L & N in one leg of the trouser and PE in the other, but I'm not convinced). CNE within a building isn't what the DNOs like to do these days (especially as they usually pass the buck to a fictional BNO) but was common enough a few years ago. The original design might then have considered the block to consist of mutiple distinct installations with separate DNO supplies for each flat - and hence would have required main bonding (if necessary) within each flat (like a terrace of houses). If the water pipe is in contact with class I equipment in another installation (e.g. the pump - presumably on the landlord's supply) then it would be classed as an extraneous-conductive-part as far as the flat was concerned (even if the water originally came out of the ground in plastic). Just a thought...
I fully understand the concept that each flat could be considered to be an independent installation like a terrace of houses, but isn't the risk the loss of neutral in a PME supply? Is that a realistic possibility in a modern (and small) block of flats as opposed to a terrace of Victorian cottages?
I can see that if a common water supply branches out to each flat, then the situation is like the terrace, but if the water supplies are independent, I struggle to see how they could amount to extraneous-conductive-parts.
If the water is pumped to each flat, the copper pipes, which are in contact with the pumps, could be exposed conductive parts and simply require that the pumps are earthed.
AJJewsbury:
Humm - that supply looks suspiciously like it might be CNE to the head (alternatively it might be split-con with L & N in one leg of the trouser and PE in the other, but I'm not convinced). CNE within a building isn't what the DNOs like to do these days (especially as they usually pass the buck to a fictional BNO) but was common enough a few years ago. The original design might then have considered the block to consist of mutiple distinct installations with separate DNO supplies for each flat - and hence would have required main bonding (if necessary) within each flat (like a terrace of houses). If the water pipe is in contact with class I equipment in another installation (e.g. the pump - presumably on the landlord's supply) then it would be classed as an extraneous-conductive-part as far as the flat was concerned (even if the water originally came out of the ground in plastic). Just a thought...
I fully understand the concept that each flat could be considered to be an independent installation like a terrace of houses, but isn't the risk the loss of neutral in a PME supply? Is that a realistic possibility in a modern (and small) block of flats as opposed to a terrace of Victorian cottages?
I can see that if a common water supply branches out to each flat, then the situation is like the terrace, but if the water supplies are independent, I struggle to see how they could amount to extraneous-conductive-parts.
If the water is pumped to each flat, the copper pipes, which are in contact with the pumps, could be exposed conductive parts and simply require that the pumps are earthed.
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