3-phase cable calculation

[LeeH]

Surely the civil works costs alone would make this project a non starter!

That’s one long run you have there.

 

[David M]

Hi,

A while ago I posted about my neighbours 3-phase generator etc....

So he's being running through diesel like there's no tomorrow and been talking to a local barn who have said he can take the power from his property to supply their kiln.

He's been measuring the his average usage over the last month or so, an on average his kiln uses 12kw, so we will run a cable for a 15mw supply to side on caution.

So he wants to bury a 3-phase supply to the kiln from the barn. The barn is roughly 1000m away. I wanted to check to see if I'm calculating the cable size correctly.

15kw/400 x 1.73 = 64.9amps

So Woud that be 21.6amps Per phase?
I'm struggling to work out volt drop to determine the CSA of the cable?

Thanks

Are you sure the barn is 1000mtrs away, not 100mtrs?
If the barn is 1000mtrs then for the 15kw supply you would require a minimum 70mm2 cable. But this gives you the bare minimum supply voltage so more information is required to do an accurate calc. Once other things are factored in i.e routing of cable, type of load, power factor of load...you are probably looking at more like 95mm2 as Lee stated. @ around £30 x 1000mtrs = £30k just for the cable! This is about the same cost as 6500 gallons of red diesel.

 

[buzzlightyear]

95mm at £31 per meter, x 1000m is £31k for cable. Might be cheaper to contact U.K. Power networks for their own supply.

or hop for one of them!