How do I wire separate 120/240V panels for Growatt 5000US* + SE Auto-Transformer & Growatt Auto-Transformer Off Grid

[kjswiley]

Hi,I would like to use separate 240V and 120V panels as shown in Signature Solars newest video. As a noob, I have attached a diagram of how I think I am going to hook it up as I am may be confused on everything, but used the dashed lines for where I am definitely confused, I figure I can feed from the lugs or a circuit breaker from the 240V to the breaker on the 120V panel. I cannot tell what is going on in the video. Thanks

edit: with additional research I believe I will put a breaker on each end and ignore the main lugs, I don't see a downside and it allows me to shut off the sub panel from the main if needed.

I have the Growatt 5000 ES* Inverters (US Version from Signature Solar)
Growatt Auto-Transformer (wired based on another user, not sure if that is correct)
Solar Edge Auto-Transformer




Signature Solar Video:

 

[HighTechLab]

You would be WAY SAFER if you connect the autotransformer L1 & L2 to the main lugs of the 120v panel. Breakers on Autotransformer feeds are bad news, and you can EASILY fry all your 120v appliances if you ever trip it or shut it off accidently.

 

[kjswiley]

You would be WAY SAFER if you connect the autotransformer L1 & L2 to the main lugs of the 120v panel. Breakers on Autotransformer feeds are bad news, and you can EASILY fry all your 120v appliances if you ever trip it or shut it off accidently.

Thank you, I will make the change...though that confuses me more.

If we use the Solar Edge auto-transformer as the example, it has L1, L2, Neutral, and Ground. If I understand correctly I would have the auto-transformers L1 and L2 going to both the 240V panel and the 120V panel. Rather than two wires in 1 auto-transformer lug would I use bus bars to connect the transformer to each panels L1 and L2? I saw in your video on the transformer for demo purposes you used two wires per lug, but what is the proper real world method? Thanks again!