Running Main Bonding Externally

[walec]

Hello All,

Been asked to change some bathroom lights and other jobs at an old house recently but preliminary inspection shows there is no main bonding in the property. Unfortunately the incoming gas is one side of the house and the water the other, both in the middle and the CU and meter at the front of the house (PME), there is no way of running one cable between the two and no way of running the cable internally (without making a hell of a mess) so the only option is to run externally. I want to mechanically protect the 10mm cable but 20mm conduit seems a bit of an overkill, so I am asking for any help/ideas on mechanical protection, its a 20M run either side of the house and I will even have to go up and around a porch as well! Customer has also said they want black as the guttering is black so I dont see many options. Thanks

 

[Benny2]

because the earth cable is mechanicly protected you can drop it down to a 2.5mm cable cant you lads?

 

[empress]

because the earth cable is mechanicly protected you can drop it down to a 2.5mm cable cant you lads?

think the origional post stated pme supply

 

[robsparky1975]

because the earth cable is mechanicly protected you can drop it down to a 2.5mm cable cant you lads?

I think you might be thinking of a tt supply main earhing conductor,main earth bonding to gas/water on a pme supply would be 10mm2 even if it had extra protection.

 

[pushrod]

Hasn't the resistance of a main bond got to be 0.05ohms or less? If that is the case OP could be struggling running it around the house because you only have 27 metres before you would have to increase the csa!

 

[Benny2]

That will be it robsparky just something that stuck in my head from my 2391, i dont come across pme much glad i hav recapped now thanks.