help with circuit design

[longshanksii]

I have been asked to provide a lighting circuit outdoors for 18 lights on a canopy. The circuit is fed from a toilet block that has a 100A supply to the meter.
The customer has now asked if they can have some extra sockets. They want a 16A commando socket around 60m from the board. They then want to future-proof to allow them to have 2 x 16A commando sockets and a 32A Comanndo socket 130m away from the board. Everything is going underground in a 100mm duct.
I'm trying to work out what size cable to use but I'm struggling to get it so the volt drop is within regs
can anybody help with this, do you think it's possible?
The supply is a single-phase supply. I think I'm still waiting for access to the meter box, but I'm assuming it is at the moment.

if you need any more information please ask

Thanks in advance

 

[westward10]

The 16A socket 60m away isn't too bad you should be able to get away with 4.0mm² SWA.
Your problems start with the 130m and I would personally put in a submain to another distribution board but you could be looking at a 50.0mm² submain if all sockets are going to be loaded on a 63A supply and you haven't got too much volt drop to worry about between the new board and the sockets.

 

[DefyG]

Agree with WW10, quick calc on app my phone shows VD of 3.3% with load of 63A at 130m using 50sqmm conductors.

 

[DefyG]

I'm trying to work out what size cable to use but I'm struggling to get it so the volt drop is within regs

Work backwards! I often start with the volt drop % required and work the formula backwards, it will lead you to a suitable conductor size!

 

[longshanksii]

The 16A socket 60m away isn't too bad you should be able to get away with 4.0mm² SWA.
Your problems start with the 130m and I would personally put in a submain to another distribution board but you could be looking at a 50.0mm² submain if all sockets are going to be loaded on a 63A supply and you haven't got too much volt drop to worry about between the new board and the sockets.

I was coming back with a 50mm, when I told them the price they decided against it, it was for future proofing but I don't think they wanted to spend so much for a possibility thanks for the help

 

[DefyG]

I was coming back with a 50mm, when I told them the price they decided against it, it was for future proofing but I don't think they wanted to spend so much for a possibility

So what was decided, be interested to know?

 

[Rockingit]

Unless I’m misreading the OP, it’s interesting that no-one seems to have factored in the losses in the upstream supply that exist already (which would in fairness be hard as we don’t know the length from meter to toilet block or the conductor sizes involved).

 

[brianmoooore]

I was coming back with a 50mm, when I told them the price they decided against it, it was for future proofing but I don't think they wanted to spend so much for a possibility thanks for the help

I'd always go for 25mm2 5core over 50mm2 3core, with the cores paired up. Considerably cheaper, easier to terminate and ready to go, if ever 3 phase makes it to the property.