How much Electricity do i need.

[ban-all-sheds]

SWA 2 CORE
UNDERGROUND
Non lighting
.
.

Outside lighting (1kw)
Inside (0.6kw)
Heater (3kw)
Pond Electrics (0.1kw)

 

[peterduckett]

Good point but I did also put heater and pond electrics.

I'm guessing this takes in to effect of initial load hence why the output is higher

Though that suggest the cable that is already their is heavily overloaded as it is no way 10 and I don't think it is even 6

 

[ban-all-sheds]

Good point but I did also put heater and pond electrics.

That doesn't matter - you aren't going to get a different voltage drop for some of your amps because they are used for different things.

12.5A is 12.5A, and 6.9V is 6.9V....

Though that suggest the cable that is already their is heavily overloaded as it is no way 10 and I don't think it is even 6

It is not overloaded from the POV of current-carrying capacity, but the load is too high to remain within voltage drop limits.

 

[peterduckett]

In a perfect world what would you do replace with 10mm and match with what RCBO

 

[Hibbo]

20A gives 4.6kW which should be plenty for what you need, and the volts drop will be within limits for a 50m run of 4mm^2 cable.

No it won't.

20A is your limit (assuming 4mm^2 cable).

No it isn't.

Fair one, I hadn't taken the 3% limit for lighting circuits in to account.

At least it gives you something to feel smug about though.

 

[peterduckett]

He is just too smart for his own pants but we thank him for it for kicking people like me into touch

Though for what he has proven to me even at that range you could only pull 31 amps while still maintaining the provision for v Drop so meaning the max RCBO i could fit on 10mm is 20 amp anyway unless I try and apply diversity

 

[bongos]

In a perfect world what would you do replace with 10mm and match with what RCBO

I'd contact an electrician for a quote and ask if I could do the groundwork myself, having the electrician specify what was required and the cable route. The spark could happily test, connect it and notify it to the LABC. I would have my completion certificate and peace of mind and be happy in the knowledge that I hadn't bodged the existing wiring to save a few quid and that if I came to sell my property at a later date, I wouldn't have to worry about not having completion certificates for new work...