call for help with long 32A SWA run

[GettinSadda]

I am having a static caravan delivered on monday and am laying cable for it from a 32A MCB. I had estimated the cable run at ~32m before the contractors built the base and dug trenches. Running up the old voltage drop calculator this told me that I would need 6mm2 cable for anything up to 36m so I bought 36m of cable knowing that I would need to keep it less than this.

Base built, trenches dug, location of CU in caravan carefully calculated and I start laying my cable. Argh, shock and horror I am about 7m short!!

Worse yet, if I am going to be laying SWA on what now seems to be a 45m run, and it can take 32A, I need 10mm2 SWA. This means that I can't even use the stuff I have already bought.

Reducing the overall max load to 20A, and using a 20A MCB would not be be a goer as electric heating will be required in the cold Scottish winters.

Has anyone got any useful suggestions?

Oh, and just to make things worse, the builders are supposed to be filling the trenches tomorrow morning!!

 

[bernardgreen]

If you cannot get the cable sorted out in time before the back filling then you could lay in a duct large enough to take the SWA you will be getting after the trench is filled.

 

[Steve]

Would a 3kw heater not be sufficient to heat a caravan? or a few 1kw ones? I wouldnt think you'd need more than 3kw of heat, leaving at least 7 amps for lights, brewing, telly.