Two Inverters

[matchedsparky]

I have an install of a 4kW system for my mcs accreditation with 6 panels on a South facing roof and 11 panels facing east. I have two inverters one for the south facing panels and one for the east, my question is can I join the ac output from the inverters together into a junction box then to the generation meter using one mcb at the consumer unit or do they require separate mcb's, one for each inverter.

 

[matchedsparky]

Can no one help, i have seen another post where this has been done on two different orientations, but in sunny boy instruction it says it must be on own mcb? Help please have install to start next week

 

[Martin Bradley]

Why not use 1 invertor. Ijust needed to ask.

 

[matchedsparky]

Because the panels are facing different orientations ie 6 are on a roof facing south and 11 facing east

 

[Markc]

What are your inverters. Sunnyboy does state one inverter and one MCB.

Another possibility is to install a 2way standalone board adjacent to the inverters and 2 x MCB's. The feed to the board can then be one circuit back to the generation meter and existing consumer unit. This could be 16A or if preferred 32A. As neither inverter can produce more than 16A's I don't have a problem with a single 16A supplying circuit. This way you manage one 16A MCB to each inverter.

 

[matchedsparky]

Thanks for your reply Mark, would the inspector have any isues with access to the mcb's being in the loft? If not i can install a two way board as you have suggested and then an armoured cable from this to the distribution board via a generation meter in the garage. Its our first install and i would like to get it right.
Many Thanks

 

[matchedsparky]

Sorry Mark, they are both sunny boys

 

[Markc]

Thanks for your reply Mark, would the inspector have any isues with access to the mcb's being in the loft? If not i can install a two way board as you have suggested and then an armoured cable from this to the distribution board via a generation meter in the garage. Its our first install and i would like to get it right.
Many Thanks

I personally can't see an issue with the two way board in the loft. After all the isolation devices are there. I have seen some early pictures of PV installations using MCBs as the isolation (not that I would use such devices as isolation) The two way is there to provide individual protection to each inverter as required by the manufacture. I would say the inspector will be more interested in knowing why you have done this over how you have done this.

I have a system in the pipe line doing just this but if possible a twin MPP tracker inverter would be an advantage.

 

[edexlab]

What are your inverters. Sunnyboy does state one inverter and one MCB.

Another possibility is to install a 2way standalone board adjacent to the inverters and 2 x MCB's. The feed to the board can then be one circuit back to the generation meter and existing consumer unit. This could be 16A or if preferred 32A. As neither inverter can produce more than 16A's I don't have a problem with a single 16A supplying circuit. This way you manage one 16A MCB to each inverter.

I agree and think this is a good idea (but I'd size cable for 32A personally) as long as you've got an AC isolator at the meter end also, I can't see them having a problem with that