Growatt 3kw wiring question

[NHRenewables]

I just installed my first Growatt and found that it did have a floating neutral without a ground reference when running on battery. When on UTL mode, voltage on the neutral is zero because it’s bonded to your main panel.

The dry contactor the Growatt has needs to be used to energize a neutral bonding relay to main panel ground when running from battery. In the event of a short, there is no earth bonding and you may end up being the grounding rod!

This topic should be addressed in length by DIY’s on YouTube for safety’s sake. Growatt should provide better guidance on installations in respective regions around the globe. Resellers should be selling these inverters with this guidance and probably include a relay as part of the purchase.

 

[NHRenewables]

I'm glad this came up... I see this GroWatt has a surge of up to 6000W. That's like a 50-60A circuit ? I'm planning on setting up in my detached garage and feeding my transfer switch in the house (about 80' away). So that's like a 6 gauge cable. Holey expensive batman! I already have a 10 gauge cable running out to the garage feeding 30A 240v subpanel. I was thinking I would just pull a 20A circuit out of that sub panel to feed the AC input of the Growatt. I don't plan on pulling any more than 15 amp load from the Growatt. But, if it ever happens, I assume the 20A breaker feeding the AC in of the Growatt will just trip... Any big problem with this?

The big point is to always endure that your breaker is the weakest link. If your breaker is sized to the wire, you’re safe.

 

[FilterGuy]

Growatt should provide better guidance on installations in respective regions around the globe. Resellers should be selling these inverters with this guidance and probably include a relay as part of the purchase.

YES!!!!! I find a lot of the inverter companies criminally negligent about documenting grounding, a critical aspect of safety.

Growatt in particular has been hard to get any solid data on. Thank you for documenting what you have found.

BTW: Growatt really should build the relay into their product (but provide a way to disable it if needed)

 

[FilterGuy]

I just installed my first Growatt and found that it did have a floating neutral without a ground reference when running on battery. When on UTL mode, voltage on the neutral is zero because it’s bonded to your main panel.

The dry contactor the Growatt has needs to be used to energize a neutral bonding relay to main panel ground when running from battery. In the event of a short, there is no earth bonding and you may end up being the grounding rod!

This topic should be addressed in length by DIY’s on YouTube for safety’s sake. Growatt should provide better guidance on installations in respective regions around the globe. Resellers should be selling these inverters with this guidance and probably include a relay as part of the purchase.

BTW: What model growat did you install?

 

[NHRenewables]

BTW: What model growat did you install?

a 48V SPF 3kW LVM

 

[FilterGuy]

a 48V SPF 3kW LVM

Thank you. I am trying to document the ground bonding/switching on various inverters. Does this look like a good representation of the inverter grounding?

 

[FilterGuy]

Also, Do you happen to have a link to the manual?

 

[mattkovo]

i just installed a Growatt 3000 - ES model and having the gfci/arc fault breakers trip also in both utility mode or battery mode. Breakers in both the main and subpanel are tipping. I have not tested solar. A couple posts above mentioned a dry contact relay but I’m not sure what I’m supposed to do there. Any updates?

Here is how I’m wired for testing purposes. My subpanel is connected to the main panel ground to ground, neutral to neutral, and hots to hots. I have the hots running from a 100 amp breaker from main panel to subpanel. I turned the breakers off on both the main and subpanel before testing. The subpanel works fine normally (and the inverter is not connected).

 

[Sojourner]

i just installed a Growatt 3000 - ES model and having the gfci/arc fault breakers trip also in both utility mode or battery mode. Breakers in both the main and subpanel are tipping. I have not tested solar. A couple posts above mentioned a dry contact relay but I’m not sure what I’m supposed to do there. Any updates?

Here is how I’m wired for testing purposes. My subpanel is connected to the main panel ground to ground, neutral to neutral, and hots to hots. I have the hots running from a 100 amp breaker from main panel to subpanel. I turned the breakers off on both the main and subpanel before testing. The subpanel works fine normally (and the inverter is not connected).

If you test with normal breakers, do they not trip?

 

[mattkovo]

If you test with normal breakers, do they not trip?

That’s exactly what I tried today. I replaced the arc fault feeder breaker with a non arc fault/gfci breaker I had delivered today and it everything works as expected now. The Leviton load panels are pretty cool with smart breakers but Home Depot doesn’t exactly stock a surplus of them. Pretty cool seeing the usage so can easily design a system around it.