supply cable sizing

[ronky]

Hi ,I have a wood cabin outside 70mtrs from house incoming supply, I was thinking of using a 35mm 2core pvc/swa, as I think a TT system would be appropriate for the cabin, owing to the distance away from house load would be allowing for diversity would be 51amps, seems a lot but it will be a live in dwelling with all requirements for cooking heating etc,am i correct with supply size Thanks ron

 

[Bobster]

Whilst cable size has been worked out to 25 or 35 due thought needs to be given to the terminal sizes and termination practicalities.

You can buy pin lugs to reduce 35mm to 25mm, since the 35mm size is only required for VD an not load, there is no issue in this solution.

Don't see why at that size you can't use the house's earthing system. Utilizing the armor of the SWA as a CPC. Unless you have extraneous services entering the outbuilding.

A switch fuse would be more ideal to provide protection for this cable, purely to meet discrimination with MCB's that I presume are going to be installed in the outbuilding.

 

[bill01803]

You would need to have an 300mA rcd not a switch at the origin

 

[Leesparkykent]

You would need to have an 300mA rcd not a switch at the origin

Where did that ball hang come from?

 

[bill01803]

Where did that ball hang come from?

Someone said you should use a switch fuse

 

[Midwest]

Think the OP is going to use swa cable.

 

[Leesparkykent]

Someone said you should use a switch fuse

Yes so why does it need a 300mA RCD?

 

[Deleted account]

Yes so why does it need a 300mA RCD?

In fact why would it need an RCD of any size?