Less bad?

[trig2]

This is how I currently have it setup, from what I've read there's no good/code way of setting one of these up with the grid attached.

I tried connecting the shed ground to the house ground without bonding neutral or connecting neutral to the house neutral and get nuisance tripping on the GFCI.

I tried bonding neutral with both grounds connected and got current flow on the ground conductor.

How bad is this setup? What are the risks in grid bypass mode? I know it's not code. From my understanding this is unsafe because the grid power doesn't have a low resistance return path in case of a short. I'm unsure if this is a concern only upstream of the inverter or downstream as well. I was pulling about 18 amps on one leg downstream and the load was exactly balanced between the two legs feeding the inverter.

I feel like it's either this or no grid input keeping the ground/neutral as is which will mean running a battery charger from grid in winter to keep it running. If I do just run a charger is there any issue with the equipment ground being shared between the house/shed. It would be very difficult to isolate them if I want to pull any circuits from the main panel into a subpanel since they're bare copper grounds. I didn't have any current on the equipment ground between buildings when in invert mode with neutral bonded, just when in passthrough mode.

If nothing else anyone have any inverter recommendations?

Side note, sparks fly when I run the internal battery charger, can't say I recommend.

Growatt doesn't say much of anything about the AC wiring but this is found in the sigineer version of the device.

 

[12VoltInstalls]

Side note, sparks fly when I run the internal battery charger, can't say I recommend.

Something is wrong with that.

tried bonding neutral with both grounds connected and got current flow on the ground conductor

Because it’s bonded at the main breaker panel- or should be

tried connecting the shed ground to the house ground without bonding neutral or connecting neutral to the house neutral and get nuisance tripping on the GFCI.

You need to draw your presently configured wiring out legibly on paper or computer and post it. Without neutral connection there is a voltage potential difference which trips the GFCI as it should but something isn’t right.

How bad is this setup? What are the risks in grid bypass mode? I know it's not code. From my understanding this is unsafe because the grid power doesn't have a low resistance return path in case of a short.

The whole setup sounds unsafe and it’s not functioning well so because it works otherwise apparently? it has to be improperly wired up.

I know it's not code

And that is the biggest alarm bell imho

Post a drawing of the static configuration at present and electricians and other similarly burdened skilled folks will be glad to pick it apart for your benefit.

 

[trig2]

I'm fairly certain the charger not working is no fault of my wiring. Having read some more on the subject (thanks filterguy) I believe I can leave it in the current state safely if I connect house/shed grounds together and never use bypass mode. Theres's no option to directly disable bypassmode however the device can be configured to shut down at a battery voltage that's higher than the grid bypass voltage setpoint. Solar assistant can control the battery charger on/off and amps in increments of 10. I should be able to prevent the device from shutting down by configuring home assistant to read the current load on the battery and apply appropriate charging current to negate that load if the battery is at a low SOC. I just need to get the battery charger replaced.

 

[12VoltInstalls]

just need to get the battery charger replaced.

Well I thought you had other troubles. Sorry.

 

[trig2]

Well I thought you had other troubles. Sorry.

Well I do, but I think my workaround using the battery charger will solve them. The battery charger should only be using the two input AC connections and the DC connections there isn't really anything to screw up, also it works for 20-30 seconds before sparks start flying which to me indicates it's wired right it just has a fault of some sort. The only other thing I can think of is how ground is handled but I wouldn't expect that to cause catastrophic failure.

 

[shopman]

Neutral and ground should only be bonded in your main panel! Your inverter output panel is considered a sub panel and therefor neutral and ground should not be bonded there. Please hire a licensed electrician to wire that for you before.......

 

[Brett V]

Your output neutral must be connected to the grid neutral. Look at the diagrams on Watts 247.
that being said…you shouldn’t be doing this if you don’t know what you’re doing.