joining cables.

[pushrod]

I have a garden shed supplied with power from the main CU in the garage. It runs down the garden in SWA, everything is in accordance to regs except possibly at a junction between SWA and T&E. The circuit starts off in T&E and on the outside of the garage wall, in a IP rated enclosure, it goes to the SWA. Should there be a fuse here? Or is that just the case just when you join a smaller cable on to a bigger one? They are both the same csa. cheers.

 

[Sintra]

I have a garden shed supplied with power from the main CU in the garage. It runs down the garden in SWA, everything is in accordance to regs except possibly at a junction between SWA and T&E. The circuit starts off in T&E and on the outside of the garage wall, in a IP rated enclosure, it goes to the SWA. Should there be a fuse here? Or is that just the case just when you join a smaller cable on to a bigger one? They are both the same csa. cheers.[/QUOTE

No as long as your join is in the correct enclosure and accessible there is no need for a fuse.

NB. Your shed should be on a TT system as it is outside the main equipotential zone.

 

[Spudnik]

Not strictly correct.

You can export the earth, however, if there are services in the outbuilding, then these must be bonded back to the MET in the house normally via 10mm G/Y.

This isnt very practical and so most people tend to TT the outbuilding and bond to the stake.

 

[Sintra]

Not strictly correct.

You can export the earth, however, if there are services in the outbuilding, then these must be bonded back to the MET in the house normally via 10mm G/Y.

This isnt very practical and so most people tend to TT the outbuilding and bond to the stake.

Didn't know that one but yes it makes sense though as stated not very practical.

 

[pushrod]

Thanks for the answers - there is no gas or water there and the little CU down there is connected to an earth spike. However, the earth of the swa (it is a 3 core, the armouring has not been used) is connected back to the main CU as well - is that ok?

 

[Sintra]

Thanks for the answers - there is no gas or water there and the little CU down there is connected to an earth spike. However, the earth of the swa (it is a 3 core, the armouring has not been used) is connected back to the main CU as well - is that ok?

The armouring of the SWA should be earthed to protect the cable from damage.

The earth from the main CU should not be connected to the earth from the shed CU. This should only be connected to your earth electrode making it TT.

 

[pushrod]

Cheers, will try and have a proper look tomorrow as to what is connected to what - i'm only going on memory at the moment.

 

[peteludman]

i thaught the shed or out house had to be made a tt system only if the house is a TNCS supply if no its ok to take earth from house.
thats what i was told by niceic anyway

 

[Deleted member 9648]

There is no requirement for outbuildings to be separated from a TNCS earth except where TNCS restrictions apply...ie construction sites,swimming pools etc. A TNCS system with RCD protection can be used for a garden outbuilding