Workshop supply on a TT

[telectrix]

no i meant fit the RCD and a MCB in a garage board at the house end. by garage board i meant a din rail CU big enough for a RCD and MCB.

 

[AA410]

LOL i think i am loosing it Its been a long day i have been stuck in a loft all day my knees are red raw but again thank for all your help

 

[JD6400]

I may be wrong but if on a stake , you can not use a metal board unless it is shielded in some way around your incoming tails ( not just the point of entry that is , but the enclosure as well ) if the tails were to touch down they would be the wrong side of the earth i think . That is if you have not brought a earth in from the supply side .

 

[johnboy6083]

I may be wrong but if on a stake , you can not use a metal board unless it is shielded in some way around your incoming tails ( not just the point of entry that is , but the enclosure as well ) if the tails were to touch down they would be the wrong side of the earth i think . That is if you have not brought a earth in from the supply side .

the reason for that is as follows. unless your Ra value is very low, then it will be too high to allow your MCB/Fuse to operate within porper disconnection times (0.2 for TT, 0.4 for TN (final circuits below 32A))
what would happen is that in the event of an earth fault, the board itself would remain live.

 

[AA410]

I found a good web site have a look at
Taking electricity outside - DIYWiki