Supply Cable

[danny124]

Hi guys, for those who have read my previous threads just needing a little advise again.

Im wiring my Shed/workshop for my Assessment for my Testing and inspection.

1. im was going to run my supply SWA cable from under my stair to my shed along my fence but im concerned about the direct sun heat that will affect the cable and the fence is not very strong and worried the assessment guy may question it.

So instead im going to bury the cable under the patio, the under the lawn.
Been looking at the BS Regs book on pg 265-270 about burial of cables and forgotten how to work out the K.m/W calculation. Is this worth working out or should i just worry about current capacity, and volt drop. If some one could just help me out on this one i be greatful


Here is the spec of what im doing, and what i got:-

* 60amp Cut out main fuse
* Going to use a 60amp isolation switch understairs
* 16-25mm 3 core SWA and use 3rd core for a better earth = 25metre run
* Board in Shed/workshop will be a 60amp RCD mainswitch at 30mA.

Cheers guys...

 

[caddy]

First off i would say the circuit sounds a little over specced for a simple shed supply. What sort of appliances / ammount are you going to be using to need a 60 amp supply ?

But 16mm 3 core would be fine, people may say use 2 core but i just prefer using a core as the earth, It can make things easier at times.

 

[danny124]

My grandad uses the shed for his Joinery machinery.

The planer use a 23amp start, which is the biggest power puller Then a few lights, heaters for the winter.

Do you think the outer core as earth is enough to satisfy the assessment guys

 

[Guest123]

TBH you'll probably find 2C harder to obtain than 3C so 16mm3C is the way to go, as long as CCC and VD work out.

If a PME earthing system then make sure all the bonding (if needed) is up to scratch. As you will have some large joinery tools in the shed think about installing dedicated circuits to try and split thngs up a bit.

 

[danny124]

Hey Lenny, Thanks for your reply...

Since i sent the post, i studied my notes, and got all the info from the BS7671 book....

Im going to run it in 3 core SWA in the ground using 16mm, worked the VD out and cable current capacity also, and only be a 40amp supply which i think is sufficient. It has had a 40amp supply running up there in 6mm for 15 years and been no problems so by going with the regs, my info i found and your info im going that way...

As for circuits the Lighting, sockets and Planer machine is going on seperate circuits.

Thanks for your Reply Lenny

Kind regards

Danny