Need help. Will this breaker setup work for my design?

[BentleyJ]

I re-drew my plan.
What would be the purpose of the main panel besides providing the only earth ground? Could I purchase the same brand panel in 125A or 100A MAIN breaker style with more spaces and just rewire everything from the old panel to the new main breaker panel then the 80A breaker could fit into the new panel because it has more space. Would this alleviate the need to have the subpanel? I would just call this 100A panel in the first set of pictures a loss and fit a bigger Main breaker panel in the same space and just wire into that. I would probably go ahead and get a 125A panel if I can find it but with 20 spaces and just rewire that for a main panel. Buy the 80A double pole breaker and insert it and wire to the growatt 12kw.

If the foregoing suggestions were confusing or misleading, apologies.
Lets back up a bit. Discard the new drawing and refer back to the original. You only need one breaker panel with more spaces (or tandem breakers as Hedges mentioned) I believe a new, larger panel is a cleaner way to go and the price of new tandem breakers has to be compared to the new breaker panel price.
Main panel or subpanel doesn't matter what you call it or what is printed on the box, its a breaker panel or distribution panel. There are a couple of differences though.
1) A main panel typically has a main breaker and comes from the factory with a N-G bond. You don't need a "Main" type breaker per se, just a way to feed power in from the transfer switch. A 60A branch breaker would be just fine.
2) A subpanel typically does not have a main breaker (but may or may not have mechanical lugs on the end of the 2 Hot bus bars) and does not have a factory installed N-G bond.
In either case we can easily configure the panel for your particular use.

Not sure where the 80A number came from, doesn't matter? The 12K is only going to deliver 50A continuous (do you have any idea what your actual peak electrical use actually is? Doubtfull that the inverter would be operating at MAX all the time) there is no need for more than a 60A breaker. Nothing wrong with upgrading to the 4AWG wire if you prefer that and wish to keep voltage drop and heat losses down. Then just use the reducing pins.

If you add up all the items connected to the breaker panel and find that the normal load will be 6 to 8kW then for sure 6AWG wire is more than adequate. The deciding factor me would be that you already have the 6AWG and the distances are short, so use what you have.

 

[SniperX]

Tandem breakers

I was looking into them until I came across this article. I have a Siemens panel with QP. This article said not to interchange them and I was already worried about the wire size so I did not want to do something else I shouldn't do. Do you think just doing one tandem among 12 slots will be ok? https://portablepowerguides.com/are-siemens-qp-and-qt-breakers-interchangeable/

 

[SniperX]

If the foregoing suggestions were confusing or misleading, apologies.
Lets back up a bit. Discard the new drawing and refer back to the original. You only need one breaker panel with more spaces (or tandem breakers as Hedges mentioned) I believe a new, larger panel is a cleaner way to go and the price of new tandem breakers has to be compared to the new breaker panel price.
Main panel or subpanel doesn't matter what you call it or what is printed on the box, its a breaker panel or distribution panel. There are a couple of differences though.
1) A main panel typically has a main breaker and comes from the factory with a N-G bond. You don't need a "Main" type breaker per se, just a way to feed power in from the transfer switch. A 60A branch breaker would be just fine.
2) A subpanel typically does not have a main breaker (but may or may not have mechanical lugs on the end of the 2 Hot bus bars) and does not have a factory installed N-G bond.
In either case we can easily configure the panel for your particular use.

Not sure where the 80A number came from, doesn't matter? The 12K is only going to deliver 50A continuous (do you have any idea what your actual peak electrical use actually is? Doubtfull that the inverter would be operating at MAX all the time) there is no need for more than a 60A breaker. Nothing wrong with upgrading to the 4AWG wire if you prefer that and wish to keep voltage drop and heat losses down. Then just use the reducing pins.

If you add up all the items connected to the breaker panel and find that the normal load will be 6 to 8kW then for sure 6AWG wire is more than adequate. The deciding factor me would be that you already have the 6AWG and the distances are short, so use what you have.

80A was suggested by Growatt 12kw manual. I underlined it near the top of the picture. I could do either 80A or 60A, and probably a new panel. I have the wire as you said, I just was trying to be careful since not really sure how to proceed.

Does that breaker need to be a GFCI since some of the outlets are GFCI in the shed? I don't think any of the breakers currently are GFCI (but probably should be) so if I need to switch them out for the GFCIs I need to do that if I am rewiring but I don't know much about that subject.

Would 3 pole be better than 2 pole if I sized down to a 60A breaker?

 

[BentleyJ]

Don't use a GFCI for the whole system breaker, just asking for nusiance trips. GFCI breakers are generally only needed for 15A & 20A branch circuits outdoors where damp or rain can create a hazard or indoors near sinks and bathtubs.

 

[SniperX]

80A was suggested by Growatt 12kw manual. I underlined it near the top of the picture. I could do either 80A or 60A, and probably a new panel. I have the wire as you said, I just was trying to be careful since not really sure how to proceed.

Does that breaker need to be a GFCI since some of the outlets are GFCI in the shed? I don't think any of the breakers currently are GFCI (but probably should be) so if I need to switch them out for the GFCIs I need to do that if I am rewiring but I don't know much about that subject.

Would 3 pole be better than 2 pole if I sized down to a 60A breaker?

These are my options unless I need to order online somewhere else. Our Lowe's and Home Depot are the worst in the nation I think. I saw one even that is equipment ground fault. I don't know which to choose (regular double pole, GFCI or QE Ground fault equipment protection type
https://www.lowes.com/search?searchTerm=siemens++60a+qt+double+pole+breaker

 

[Hedges]

The article talks about mixing brands, but then lists two different models from Siemens (maybe they bought a different brand?)

I'm using Square-D QO, and tandem QO breakers.
I think it is best to start with a panel big enough to fit anticipated single and dual breaker requirements. But if you run out of spaces, replacing some with tandem is economical and easy.

GFCI and AFCI, required for many newer applications, are single and dual but not tandem, more reason to go with a big panel.

I did one project with a 12 slot, 24 circuit, 125A panel. It is quite stuffed, and I may retire some circuits to fit a backfed breaker so it can select between grid and backup. I used a bunch of 20/30 and 30/20 side by side tandem breakers to make 20A and 30A 240V circuits.

I've now stockpile half a dozen QO panels, 125 & 200A, single and 3-phase, for my planned projects.

Since yours isn't behind sheetrock yet, it would be a good time to select a new 40 +/- slot panel of whatever brand you prefer, for future expansion.
Run 2" EMT conduit to attic and basement so you can stuff wires to it later.

Edit: Solar shed, not house, maybe 20 slot is plenty.
For the QO I uses, 125A is available 12 and 20 slot. The 40 & 42 slot are 200 or 225A, more expensive.

 

[SniperX]

The article talks about mixing brands, but then lists two different models from Siemens (maybe they bought a different brand?)

I'm using Square-D QO, and tandem QO breakers.
I think it is best to start with a panel big enough to fit anticipated single and dual breaker requirements. But if you run out of spaces, replacing some with tandem is economical and easy.

GFCI and AFCI, required for many newer applications, are single and dual but not tandem, more reason to go with a big panel.

I did one project with a 12 slot, 24 circuit, 125A panel. It is quite stuffed, and I may retire some circuits to fit a backfed breaker so it can select between grid and backup. I used a bunch of 20/30 and 30/20 side by side tandem breakers to make 20A and 30A 240V circuits.

I've now stockpile half a dozen QO panels, 125 & 200A, single and 3-phase, for my planned projects.

Since yours isn't behind sheetrock yet, it would be a good time to select a new 40 +/- slot panel of whatever brand you prefer, for future expansion.
Run 2" EMT conduit to attic and basement so you can stuff wires to it later.

Edit: Solar shed, not house, maybe 20 slot is plenty.
For the QO I uses, 125A is available 12 and 20 slot. The 40 & 42 slot are 200 or 225A, more expensive.

I would have had a larger panel but the husband bought it and installed it against my protests. So, do you think I need to make that breaker a GFCI or AFCI since there are GFCI plug-in receptacles in the shed? He did not put GFCI breakers in, but if being powered through the Growatt, if I make this a GFCI breaker, will it then cover me for the new applications? I am going to get a 20-slot 150A panel. We will be building a house about 50 yards away, so that will have a bigger panel. This is just to cover this under 500' shed. Really appreciate your help. You and BentleyJ. I guess I did not make my title provocative enough to get anyone to read it. lol
I think they were saying in the article not to put QP (1-inch wide breakers) with QT (1/2-inch breakers) I can't say what would be wrong with that except they want you to buy more breakers instead of using what you have.

 

[Hedges]

Either GFCI breaker or GFCI outlet provides shock protection, including downstream outlets connected to correct terminals of GFCI outlet.
Those should be used where you will be in a wet location like kitchen, bath, garage, outdoors.

I think I've had GFCI outlets stop working, but breakers that only occurred after a short circuit.
Some outlets are marked "WR" and intended for outlet itself being damp locations.

AFCI is newer, now required by US NEC or other rules to prevent fire from arcing in bad connections.
It is said that many house fires are caused by arcing.

 

[G00SE]

Don’t yet have much to contribute but wanted to jump in here so I can stay current on the thread!
Very relevant to my brain and can’t wait to read thru these 2 pages already!
Thanks for bringing me in the loop @SniperX

 

[SniperX]

Ok, I am back here again with a few questions.
I have been thinking about this. Since I am not using the AC input on the Growatt (the generator is wired directly to the transfer switch and not to the Growatt AC input) and the middle section of the transfer switch is now 4AWG going to the main breaker on the panel (rated 90C so 140A?), do I really need the breaker they call for since the manual states it is for a way to disconnect from AC input during maintenance? My transfer switch can do this.

This is a screenshot from the manual talking about the 80A breaker. I don't mind getting a breaker but it can't be one that goes in the Breaker panel because I can't wire the AC output to the panel. I need to go through the transfer switch. So, if you think I still need a breaker for overcurrent protection and not just for a cutoff switch, it would have to go between the transfer switch and the inverter.
My 6AWG wire is rated at 90C. I found a chart that says 105A at 90C.

I did purchase another Siemens 150A panel with 20 slots.

If I need the breaker after all, and it goes between my transfer switch and my inverter, is this what I am looking for?
I am lost on that aspect. I think it needs to be attached to a DIN rail of some sort and most likely inside a metal box for protection and I don't want an Amazon Chinese one.

Can you tell me if I am understanding it right and if this line of breaker (type b or c) is a good one? If this won't work (120/240V) Which one do I need? I don't know how to look for it. Again, I appreciate your help.

https://www.mouser.com/ProductDetail/Weidmuller/2478520000?qs=sGAEpiMZZMuGSqhhLqSWxTuQ9pwTpWruR1XEoCKOaC75LH7jwruhSw%3D%3D