5 core SWA use with paired cores for single phase?

[oldman2]

I have a run of 30mtrs to my workshop and I have a drum of 5 core 2.5mm SWA

Using just 2 cores plus earth core clipped surface gives me around 28amps max on 30mtrs. I really need 32 amp min for my plasma cutter.

Can I double up by colour sleeving 4 conductors as brown/blue to lower the voltage drop and increase the current capacity of the cable?

How to work out the max amps capacity if pairing is allowed?

Of course I would use both the earth conductor and swa both as earth conductors.

 

[comms]

You can.

I would be inclined to terminate the cpc at an insulated box at workshop end, then TT (earth rod) the workshop cu/supply.

 

[RF Lighting]

I would be inclined to terminate the cpc at an insulated box at workshop end, then TT (earth rod) the workshop cu/supply.

What on earth for?

 

[oldman2]

I would be inclined to terminate the cpc at an insulated box at workshop end, then TT (earth rod) the workshop cu/supply.

What on earth for?

I take it you didnt mean the play on words then?

 

[RF Lighting]

No, there was no pun intended.

OP, do you know what your earthing supply type is? There is some info in the wiki to help you, or you can post a photo and someone on here will be able to identify it.

Are there any other services entering your workshop such as a water supply or central heating?

 

[oldman2]

House Supply is TNS, earthing is by way of boards clamp, not soldered lug.

There are no other services to the workshop at present, this will be the only supply to it.

Normal use will just be lighting and 13 amp sockets, but I will on occasion use the plasma cutter and its needed 1.5hp compressor together.
The plasma has a max current of 32amps though I doubt very much it will get to anything like that load with my usage.

I intended to use a workshop CU with 1 lighting and 1 ring main and 1 32amp industrial socket for the plasma.

 

[Pensdown]

How to work out the max amps capacity if pairing is allowed?

Of course I would use both the earth conductor and swa both as earth conductors.

You work it our for 1 cable with all derating factors etc and then double the result for current and 1/2 it for VD. You then apply a grouping factor if the cables/cores are not spaced more than 2 cable diameters apart.

Your 2x2.5mm @ 32amps over 30mtrs will give you a VD of around 7.93V which is around 3.4% so I would go with it.

 

[oldman2]

Thanks for that, it will do nicely