Cable size between inverter and consumer unit

[binky]

So that means that the electrician can use this consumer unit and add the new 6mm cable to the inverter without the need of a second consumer unit, right?

Only if it can be configured with a third neutral bar, what's known as a 'high integrity board'. I've not fitted BG for years, so don't know how they come these days. If it hasn't got the extra neutral bar, you could remove one RCD and fit RCBOs for existing circuits, and a MCB for the inverter. Unless the cable run requires a RCBO to comply with regs, inverters are better off without them.

Still I wonder if I need beside of the 6mm ac cable from the inverter to the consumer another 6mm ac cable from the hybrid inverter to the outside electric connection? I wouldn't think, but just want to make sure, as it will be a good chance now but bad in the future )

If you ever needed to run to the outside, it's simple enough to run cable in conduit down the outside

 

[SUNBATH]

The 2.5mm/4mm/6mm cable from the inverter to the CU allows the inverter to send current from the PV panels into the CU, to reduce the current being taken from the "outside connection".
That's all you need, no need for a cable from the CU to the "outside connection".
The breaker in position 3 with the label torn off has a 40A rating, suggesting a high-current device such as a shower was, or may still be, connected to it?
The breaker in position 7 with no label has a 30A rating, the same rating as the "Existing Sockets".
So maybe an extra set of sockets have been added since the house was built, in an added conservatory perhaps?
If you're not sure what it does, switch it off and hope nothing stops working.
Then it may be be a "spare way" you can use for the inverter.

Hi. Thank you. The consumer unit was new put in a year ago when we started the extension. So everything which is not labelled is truly free.

So this means we need not an extra cu for the PV, which would be brilliant.

Thanks as well with the explanation with the extra cable from the PV to the outside connection.

As suggested here before I got a 6mm cable and it is now in place for the electrician.

Thank you for all your help guys

 

[monkey5]

The electrican might need a cat 5 cable for a ct clamp, I did for mine but others will no better.