certificate

[mike]

hi. i wired a cupple of sockets and lights in a shed the other day it was fed with 4mm swa i put a sub main in. because there was structual steel it needed bonding so i put a earth steak in so the shed was a TT. my question is, on the certificate do i put the details of the cu where it is fed from on the certificate or do i treat the shed like its seperate and do the certificate just for the shed. thanks

 

[Cirrus]

good question Mike, but I am not quite sure. When we used to do garage power for the councils I am sure we did two seperate certs.

 

[EasyFox]

In this case I tend to do 2 EIC's, one for the submain & one for the outbuilding.

 

[markthespark]

Hi why when wiring an outbuilding do people put a TT system in, why dont you use the house earthing system??

Cheers

 

[Cirrus]

Not sure Mark - I always use the main earth but depends. For example, if I am wiring an outhouse I will take a 4 mm t&e as the main feed straight from the main board.

 

[slrichardson]

I thought the reason you put an earth rod in is because you are not supposed to export the installation earth out of the equipotential zone of the house. Especially with a tncs system.

 

[EasyFox]

I thought the reason you put an earth rod in is because you are not supposed to export the installation earth out of the equipotential zone of the house. Especially with a tncs system.

True you are supposed to get permission from DNO to export the main earth.
I go with the thinking that if the outbuilding is further than 3mtrs from main building then I TT.

 

[wayne]

easy fox/slrichardson -can you expand on your answer please .i've done the odd site temps and this business about exporting the earth is useful knowledge where is this information from and whats DNO?

 

[mike]

ive been told if bonding needs to be done in a out building and the csa of the earth suppling the out building (4mm swa) is smaler than the required size of the equipotential bonding conductor which is 10mm for pme. so the 4mm earth is to small to use as a bonding conductor. so by instaling a earth electrode TT and discarding the incoming earth (put in conector and used plastic box for glan ) this ment i could equipotential bond in 6mm (page 29 osg) hope every one can understand this