UK Solar SWA cable run 10mm or 16mm

[Paul_Wales]

Morning, I was just looking for some advice on what other sparks would do for the following scenario:-

A detached Garage is going to house a 7.4kw Solar Array and around 12kw of battery storage. The supply needs to return back to the main house (cable run approx. 22m) to DNO/consumer location. Would you opt for 10mm SWA or 16mm SWA ?

 

[bill01803]

I'm between 16 and 25 to obtain the correct volt drop

 

[kropaske]

At full whack you will have circa 1.4% for 10mm and 0.9% for 16mm VD, that will be at nominal voltage, inverter will supply slightly higher voltage. You should just be OK with 10mm unless there are extremely long and power hungry lighting circuits

 

[Risteard]

Caveat first: I haven't done any PV installs in quite a number of years. However, when I was doing them it seemed to be generally accepted to try to keep the volt drop within around 1%.

 

[kropaske]

Best thing would be to ascertain max VD on existing circuits and go from there. It could be the case that 6mm would be adequate.

 

[davesparks]

As I understand it with solar the lowest possible volt drop is desirable. So really the largest reasonable cable size woukd be best.

 

[Mark42]

Probably not worth it for 22m, and there may not be room in the house, but you can always do as I did and run MV dc direct from the panels on 6mm or 10mm 2-core SWA, then put the inverter next to the CU.
I've never understood PV companies' obsession with always putting the inverter/s next to the panels, then running 230Vac back to the house, often in huge and expensive cable.

 

[Lister1987]

Not sure where I remember if from but I recall there being something about SWA actually being prohibited in PV installs? Whether that was between modules/strings or the array and the consumer unit I'm not sure, might be talking out my arse though so happy to be corrected

 

[MJPD29]

Not sure where I remember if from but I recall there being something about SWA actually being prohibited in PV installs? Whether that was between modules/strings or the array and the consumer unit I'm not sure, might be talking out my arse though so happy to be corrected

Answering questions at 4.01am?? That’s dedication

 

[Lister1987]

Answering questions at 4.01am?? That’s dedication

That's also insomnia from 3 under 6s and the determination that I WILL have some time to myself