Exporting PME

[chloebear]

I have a distribution cable to run for a domestic garage conversion - run length 40M - the main house is part of a PME system. There will be a fare loading on the new converted garage as it will have electric shower & heating. Is it feasable to export the earth from the PME or would it be best to have the garage conversion as a TT?

 

[Spudnik]

Hi and welcome to the forum.

Very long story short, TT the garage, especially as you have services going in there (water).

Also, you will need to install a fairly large cable to deal with the electric shower in there due to the loading and length of run and you also need to consider the route and if it would require RCD protection at the supply end. Obviously the garage CU will more than likely need it.

Depends on the installation method used.

Make sure you carry out all the calcs before you even begin the install.

Could be a very costly mistake if you undersize the supply cable.

 

[Guest123]

Hey.

100% make the garage a TT installation.

So much easier to achieve.

Cheers.

 

[chloebear]

Thanks for the pointers. I was planning to use 16mm twin SWA and TT the garage end. The route will be all external attached to a garden wall.

 

[Guest123]

Hey Chloe

Just a thought. is your existing supply big enough to cope with the large additional load that you will be adding?? i.e DNO cut-out fuse and supply tails??

 

[chloebear]

100A BS1361 cut out with 25mm tails - I will be taking the distrabution cable off before the house CU.

 

[Guest123]

Cool.

Worth doing a max demand calc though just to be totally sure.

 

[johnnyb]

Just a pointer Chloe, but taking the sub main off before the CU won,t make any difference, you still only have a 100 amp incoming supply, and i think thats why lenny was saying about your max demand?