Future Proof Wire for Solar Panel

[jonwestuk]

Hi All,

I am nearly done with a re-wire of my house but it occurs to me that I may want to put in solar panels at some point in the future. As I have all the walls open (and am desperate not to touch them ever again!) I am thinking of running a cable from my attic to my main fuse board.

The questions is - if I keep the inverter/batteries in the attic - what diameter wire would be recommended from the inverter back to the mains location? Info on the web is sparse on this topic with some suggesting a 6mm cable. That seems large to me (I can imagine that may be required from any batteries to the inverter) but is that really required all the way back to the mains?

Thx

Jon

 

[DetlefSchmitz]

I some situations you can't afford any significant volts drop down that cable, or the inverter may stop working.

I would put in trunking and a pull-string to give you flexibility later. And maybe a separate channel for possible instrumentation.

 

[leeco]

12v solar panels wil run higher than 12v maybe 18v in direct sunlight and at the other end you will have a MPPT controler that will turn the 18v into 12v.

I have fitted solar panels and used 6mm2 cable but that was for off grid.

Maybe you should do what DetlefSchmitz says and let the instalers put what cable they think is right.

 

[pjcomp]

Depends how much roof area you have and therefore how many panels you could accommodate. Most domestic roof areas can't fit more than 4kw-worth (at present panel capacities) in which case a 4mm cable would be ample. But if the panels are that much better by the time (if) you fit them, 6mm would give you some wriggle room. The conduit-and-drawstring idea is a good one but you'd want a straight run, no corners/bends if, come the day, you need to pull through a 6mm cable.

pj

 

[pjcomp]

12v solar panels wil run higher than 12v maybe 18v in direct sunlight and at the other end you will have a MPPT controler that will turn the 18v into 12v.

If the installation follows the usual pattern of inverter up near the panels, it'll be 240V AC running down the drop cable to the consumer unit, not the 12V panel output.

All sorts of variables depending on the eventual installation, but as you're trying to future-proofall you can do is plan for the msot likely event, not all of them!

pj

 

[jonwestuk]

Thanks all,

6mm it will be and I guess this will need to be a limiting factor in the set-up that I go for. The conduit is a great idea, however not practical in this situation as the meter is in the middle of the house so the cable would need to descend 3 floors and then channel 5 meters across.

I appreciate the responses

Jon