installing pv on existing sub boards

[poheZ]

Hi all



I have a sub board which is supplied by a 2.5mm 2 core SWA with a 30m run from the origin. The sub board is in a garage and has sockets and lights wired to this board. Am i right to assume that the volt drop from the origin to the sub board will not exceed my g83 voltage parameters and that the 1% volt drop requirment will be met from the cable going to the inverter from the sub board? Does this sub main cable have implications on the installation and its ability to 'push' power back to the grid?

Any comments would be gratefully recieved.

 

[rich.250]

I wouldn't assume anything. Do the calc
And make sure. It's not very often in domestic you'll find a sun as low as 1% vd

 

[jason121]

To small a cable try 6mm
Try using SMA software to calulate it

 

[rich.250]

Or......
VD= L x Ib x mV/A/m /1000

 

[MikeyT]

ummm... I agree with rich...

 

[jason121]

always wondered what those letters meant in the big RED book

 

[jason121]

We never use anything below 4mm on PV thats within a meter of CU and im sure the PV boys would agree

 

[rich.250]

I just always calculate. Lol.

 

[solarsavings]

I just always calculate.

That's what the blokes who use 2.5mm say as well ;-)

 

[rich.250]

well I'm Not made of money... Lol
If the CCC and VD are fine. It's a winner. Lol

 

[sedgy34]

always wondered what those letters meant in the big RED book

You have same as me the new RED one

 

[moggy1968]

it's inadequate, you need a new cable

 

[poheZ]

what is it inadequate to do?

 

[moggy1968]

to carry the AC voltage, the voltage drop is too high.
you might get away with it if your planning to run the DC through it, depends what your DC voltage is going to be, but as I read it that's not what your intending to do.