Cabling

[DaveH]

My plans don't currently include PV panels but during the construction I thought it would be prudent to put some infrastructure in incase I decide to add them at a later date. Is it as simple as putting in some cable from the loft area to the plant room and if so what size and type of cable would I need? I am on 3ph mains if that makes any difference.

 

Thanks

 

[ProDave]

I would put 3 pairs of DC solar PV cable from the roof to the plant room. Probably 6mm, you buy it as red and black, so three of each kept as pairs so you know which is which.

 

And (if the CU is not in the plant room) a spare feed from the CU to the plant room for the inverter.  Probably a 5 core 2.5 or 4mm to cater for a 3 phase inverter.

[DaveH]

Thats great, thanks. The CU is in the plant room so no issues there. If I speak to my local electrical merchant and ask for '6mm DC solar PV cable' I assume they will know exactly what I need?

[PeterW]

This is where I differ on view and prefer micro inverters as they just export 230VAC to the house and don’t need anything else than a length of standard T&E from the roof to a suitable connection point in the plant room. 

[DaveH]

So it would be an option to run several lengths (?) of T&E from loft space to plant room and have the inverters in the loft? Any advantages/disadvantages to each system?

[ProDave]

Micro inverters are a good solution but expensive.

 

The one thing i would not recommend is one big inverter in a roof space, they can get very hot and shorten their life.

 

Decide what you may want and make a decision.

[Reiver]

Micro inverters are meant to be better  if some of the panels are likely to be shaded  at some point, as they optimise each panel's output, rather than the shaded panels dragging down the output of the rest. I'm thinking of going for a bit of a hybrid system with battery  backup so I can run all lighting (low voltage LED) off solar - but then I am a bit of an OCD electronics nerd