Dual inlet box gut check

[DIYSol]

Hey All -

Would appreciate a gut check here. I have a 50mp interlock with 50 amp inlet already set up in my home, but I'd like to add the ability to feed into that interlock from an indoor inlet used with a battery bank/solar inverter as well, or at least have the option if needed in an emergency. I picked up a 100A/100A transfer panel for super cheap (<$70), so trying to make this work with the setup as best possible.

Below is the setup I'm currently looking at. Would keep the same 50A outdoor inlet on a 50A interlock breaker, add the transfer panel in between them, then on the second part add a 30A indoor inlet. Since the 50A breaker on the interlock is preventing draw beyond that from the house my understanding is the 100A transfer panel breakers should be fine, but my concern is the 30A inlet. If I can't find a compatible 30A breaker for the transfer panel should I add some sort of 30A main lug load center in between the 30A inlet and the 100A breaker on the transfer panel to ensure the inverter doesn't get too much power pulled?

Any concerns with this setup?

 

[400bird]

The simple solution, in my eyes, would be a 50 amp socket inside to match the available breakers.

 

[ricardocello]

Nice Drawing.
I would run 6 AWG wiring for all 50A circuits, including to the Inside Inlet.
You may want a bigger indoor setup later.
There is no such thing as NEMA L14-50, so I use CS6365/CS6369/CS6364 (california 50A locking).

Unfortunately, most L14-30 inlet devices do not accept 6 AWG, it's too big, which is a pain.
I've made some short 1' L14-30R to 50A locking cables for my setup so I can use 50A or 30A locking power inputs.

on the transfer panel to ensure the inverter doesn't get too much power pulled?

The breakers should protect the wiring, not the device.
But I do see why it would be more convenient to build one in the panel.
See my next post below.

 

[ricardocello]

Someone will also likely point out that the wiring from the inlets to the main panel have no protection unless the external devices plugged into them have a built-in breaker <= 50A. If a fault developed anywhere on the left side or lower part of the diagram, the main panel breaker will not trip, because the 50A breaker in the main panel won't see any of the excess current. The 100A breaker only protects the wiring from the interlock to the main panel, and if it is 6 AWG, it's not adequate.

I've got an indoor and outdoor breaker box and inlet setup.

Here are some inexpensive indoor and outdoor small panels rated 70A, but there are other choices.
You can put 30A or 50A 2-pole breakers in as desired.
https://www.amazon.com/Square-Schne...4-Circuit/dp/B00002NB3V/ref=asc_df_B00002NB3V
https://www.amazon.com/Square-Schne...4-Circuit/dp/B0002YSPPG/ref=asc_df_B0002YSPPG

 

[DIYSol]

Thanks to both of you for the input!

Actually just happened to receive the transfer panel and found they are Eaton CH2100 breakers so since the panel lugs are rated for 6 AWG I'm thinking I'll just swap out both breakers to be either two CH 50A's for two 50A inlets or a CH 50A and a CH30A with a 50A and 30A inlet. Then I'll use main 6 AWG wire from transfer panel to interlock! Obviously will make sure the interlock linkage from the transfer panel will still work but since I'll grab CH breakers hoping it should!

I think this would satisfy all concerns about wire rating and protect the units themselves for $20-40 more of new breakers but appreciate if anyone sees an issue!