Solar PV volt drop and cable sizing.

normanton · Jul 10, 2015

Morning gents, just a quick one. I've posted this already on the Solar PV forum but thought I'd add it here too as VD and cable calcs are always a good topic of discussion.
So I have a Solar PV system to install this weekend, its a 10KW single phase system on a farm. I'm going to be running a 2-core SWA from the substation to the invertor, the cable is going to be buried and as you know there needs to be <3% VD. My cable calculations are coming back with results of up to 95mm for some reason, this can't be correct surely? Any constructive help would be much appriciated, Cheers, Lee

Richard Burns · Jul 10, 2015

I thought solar was 1% volt drop but I could be wrong, however if you are pulling 45 A on a 120 m run and the inverter is at the end of the run then I get either 95mm² or 120mm².

V/A/m = Vd / A * m = 2.3 /(45*120) = 0.0004259
so 0.43 mV/A/m
for which 95mm² should be OK as it is not taking the full current.

Worcester · Jul 10, 2015

Have you read all the responses in the Solar PV forum (your duplicate thread)?

3% at your peril and professional reputation.

http://www.electriciansforums.co.uk...anels-forum/103663-cable-sizing-solar-pv.html