First attempt at design

[Duncirvine61]

This is my first attempt at my design for my garage and I have some questions.
I am looking for advice on how to get power back to the main consumer unit so I can use the
solar power in my home. But the garage CU is powered from the main CU via a 40amp fuse.
Also do I need a DC isolated between the solar panel and the inverter and do I need an AC isolator
at th AC output to the garage CU.

 

[Steve_S]

An A-Typical installation will have the following:
Solar Array to a Combiner (usually with each string to a breaker).
Many jurisdictions will also require a Master shutdown to disable the solar array.

VAC Inbound from Grid to AIO of course goes through a breaker to the AIO.
This is a Non-Export unit so no power out to Grid, nothing special is required as it can only pull Grid Power to charge batteries.
* It may be preferable to have the circuit from your mains go through a standard switch to a "plug outlet". Then wire a a plug onto the AIO VAC INPUT, so that 1) You can turn off the outlet by switch &/or 2) unplug it if required.

VAC Outboud from AIO.
Typically, the AC is wired to a Subpanel which in turn feeds the required circuits wired to it.
5000W ÷ 220V = 22.7A (round UP to 30A) is what that AIO can output and what it can support.
Wiring from Garage to Home would ALSO Require an equivalent circuit going back to house as you have presently. You could feed that wire directly from the AIO to a subpanel within your house entering the panel with a 40A Breaker.
YES, Have a Breaker between your AIO & any subpanel. As you are in the UK, you have full access to DINRAIL Boxes, Breakers etc which can really make it simpler.

WORD !!!
Do NOT EVER skimp on Fuses & Breakers and ensure your wire is correct for the loads (I generally suggest going up 1 level/grade above) what your "immediate" need it. A FACT WE ALL ENCOUNTER, we build what we think will do for our needs, 90% of the time we find ourselves upgrading within a year because we underestimate OR added more goodies that we gotta power. Always consider that ! Especially if you are running copper underground etc... You ONLY want to dig that trench "once"...

 

[Duncirvine61]

Thanks a lot for the feedback!
To summarise I should add the following:

A DC isolator between panels and AIO
A plug or switch between the 40amp out from house to the AIO
From the AIO to the garage consumer unit should we add an AC isolator and a fuse?

Also as it will not go back out to grid Will it still be able to supply the home CU?

 

[DIYrich]

Can you export to the grid? If so:
Grid connected inverter
40 amp line goes to the grid input.
Limit grid input/export to 30 amps (80% of 40 amp line).
Garage goes to load connection.
Load power source priority is PV and battery.
PV powers garage, excess to charge batteries.
Any excess over that is exported to grid (40 amp line).
If you can put CT's at the main panel, then you can do a whole house setting.

 

[Duncirvine61]

An A-Typical installation will have the following:
Solar Array to a Combiner (usually with each string to a breaker).
Many jurisdictions will also require a Master shutdown to disable the solar array.

VAC Inbound from Grid to AIO of course goes through a breaker to the AIO.
This is a Non-Export unit so no power out to Grid, nothing special is required as it can only pull Grid Power to charge batteries.
* It may be preferable to have the circuit from your mains go through a standard switch to a "plug outlet". Then wire a a plug onto the AIO VAC INPUT, so that 1) You can turn off the outlet by switch &/or 2) unplug it if required.

VAC Outboud from AIO.
Typically, the AC is wired to a Subpanel which in turn feeds the required circuits wired to it.
5000W ÷ 220V = 22.7A (round UP to 30A) is what that AIO can output and what it can support.
Wiring from Garage to Home would ALSO Require an equivalent circuit going back to house as you have presently. You could feed that wire directly from the AIO to a subpanel within your house entering the panel with a 40A Breaker.
YES, Have a Breaker between your AIO & any subpanel. As you are in the UK, you have full access to DINRAIL Boxes, Breakers etc which can really make it simpler.

WORD !!!
Do NOT EVER skimp on Fuses & Breakers and ensure your wire is correct for the loads (I generally suggest going up 1 level/grade above) what your "immediate" need it. A FACT WE ALL ENCOUNTER, we build what we think will do for our needs, 90% of the time we find ourselves upgrading within a year because we underestimate OR added more goodies that we gotta power. Always consider that ! Especially if you are running copper underground etc... You ONLY want to dig that trench "once"...

Thanks a lot for the feedback!
To summarise I should add the following:

A DC isolator between panels and AIO
A plug or switch between the 40amp out from house to the AIO
From the AIO to the garage consumer unit should we add an AC isolator and a fuse?

Also as it will not go back out to grid Will it still be able to supply the home CU?

 

[Duncirvine61]

Can you export to the grid? If so:
Gird connected inverter
40 amp line goes to the grid input.
Limt grid input/export to 30 amps (80% of 40 amp line).
Garage goes to load connection.
Load power source priority is pv and battery.
Pv powers garage, excess to charge batteries.
Any excess over that is exported to grid (40 amp line).
Of you can put CT's at the main panel, then you can do a whole house setting.

I think what your saying is I could use the output of the 40amp breaker to feed the main CU so split the main CU busbar into 2 so some are fed only from the grid and the rest have an option of grid and battery feed. So would need an automatic transfer switch to switch between grid and the solar battery?

 

[DIYrich]

I think what your saying is I could use the output of the 40amp breaker to feed the main CU so split the main CU busbar into 2 so some are fed only from the grid and the rest have an option of grid and battery feed. So would need an automatic transfer switch to switch between grid and the solar battery?

Output of 40amp breaker feeds the AIO.
AIO feeds the CU.
No need for transfer switch. But, if grid goes down, so does your CU.
However, when you shut off the 40 amp breaker, the Grid Inverter can go into island mode and supply power to the CU.
Some AIO have an isolation circuit and does that automatically.

If you want to feed the Main Panel during grid down, you need a cutoff (ATS, or some type of Isolation Switch) between the meter and main panel (up to 40 amp limit of the breaker).

Note: 40a is almost 10 kW. If that is your desire, then EG4 18kpv (equivalent for EU) is worth considering.

Note: Fixed typos in my original post.

 

[Duncirvine61]

After the great feedback here is my design.
I have 2 questions do I need an Earth rod for the solar panels.
And the question I cannot solve is how to get the solar panels power back to the main CU.
Note Ze at garage consumer unit is 0.23ohm.