Outside tap isolator

[gas4you]

I do not know this exact point either other than the gas is supposed to be within 600mm and before the first T so usually will be earthed outside the property on an external meter, but it is in the electrical regs. There is also a grey area that the prv discharge from a combi should be isolated from outside as well

 

[Softus]

No offence intended, but you seem to have invented the need to insulate the tap from the internal copper pipe.

 

[gas4you]

No offence taken, but I can assure you it is covered in the electrical regs and was also pointed out during my Part P course.

 

[Softus]

I remain skeptical; not because I don't want to believe you, but because it defies common sense.

 

[gas4you]

Its all to do with this equipotential zone and that everyting inside this zone is at the same potential so if you touch a live copper pipe every other copper pipe is at the same potential so you should get a shock across your chest, although if a copper pipe was live then a mcb, fuse or rcb should have tripped.

I only know what I have been taught on Part P and informed by sparkies whom I have been working with.

I hasten to add that although Part P qualified I always look for the opportunity to let the sparks do all the work and sign it off. I wish I'd never bothered with it sometimes, more hassle than its worth and I have time for

Just noticed op must be sparky from his history of posting on electrics forum. Perhaps he could enlighten us on this issue

 

[RF Lighting]

IMO the chance that the outside tap could introduce a potential into the zone is incredibly remote, it does not really need to be bonded, but there can be no detrimental effect in doing so.

The mains cold water is main bonded in 10mm² within 600mm of the outside tap and the supply pipe entering the building, and the supply is in MDPE, so all bonding is within the regs.

The 6.0mm² earth wire you can see is local cross bonding to the hot water pipework and the sink which is now no longer required under the current edition of BS7671

I have never seen, or heard of the need to bond a PRV pipe which exits the equipotential zone