Growatt N-G confusion

MT off grid

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seems like if I want to have AC input to charge batteries with grid power I need to remove the NG bond screw in my panel and use the AC input on different phases to keep a ground and the inverters happy. If I want to be completely off grid with no AC input for charging I need to install the NG bond screw in the panel and also add a earth ground but in either case I would leave the connection between the AC in neutral and AC out neutral. Would I be safe to use my main water line to connect a ground clamp to so that I have an earth ground? If I do it this way and decide to go back to using grid power for charging would I need to remove the ground going to water line so i don't have two grounds?













































copy of post #61





If I want to run completely off grid with no AC input I remove the neutral jumper wires, add the N-B screw back to my panel then what do I do for a ground? Does it just become floating like a generator or should I still ground it to my house? If I still need to ground it can I just get a ground clamp amd connect it my my water main next to the other ground clamp that is for the house?"
 

timselectric

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Your ground should come from the ground bar in your main service panel. No matter which way you want to hook up your inverter. The only thing that changes between having or not having grid power connected to the inverters. Is how you handle the neutral and N/G bonding.
 

MT off grid

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Your ground should come from the ground bar in your main service panel. No matter which way you want to hook up your inverter. The only thing that changes between having or not having grid power connected to the inverters. Is how you handle the neutral and N/G bonding.
 

MT off grid

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Okay, was hoping to be able to stay away from getting involved with the house panel and using my water main ground since it's already being used and in a roundabout way is connected to my panel and is also 4 feet away from my inverters, Trying to keep the amout of wires I need to connect or disconnect to a minimum so I can easily switch back and fourth based on my needs
 

timselectric

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Okay, was hoping to be able to stay away from getting involved with the house panel and using my water main ground since it's already being used and in a roundabout way is connected to my panel and is also 4 feet away from my inverters, Trying to keep the amout of wires I need to connect or disconnect to a minimum so I can easily switch back and fourth based on my needs
Until a recent code change. That would have been acceptable. If you are not going to be inspected, it would actually be ok.
 

MT off grid

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No inspections being done, doing everything as a temporary install, when I talked to the local inspections office I was told that of its temporary they don't have any need to do an inspection, similar to having a transfer switch, as long as the switch is inspected they can't control what is plugged into it to supply power, I'm not trying to cut corners or do anything unsafe, last thing I want is to have an issue amd get a home insurance denial
 

MT off grid

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See Pic, not correct colors but highlighted what I'm asking.















Green is a temp ground going to my water main, I have the N-G bond screw in place, yellow line shows the "bond" I did between the AC in and AC out neutrals in each inverter. I didn't have room for more wires in the inverter Terminal blocks so I did it in the breaker panel. Does this look correct to you ad long ad I do not connect the inverter AC input to my main panel and stay off grid?
 

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timselectric

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If you don't connect AC input to the grid power. You don't need to connect AC input neutral and AC output neutral together. Otherwise yes, it looks fine.
 

MT off grid

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Oh, so if off grid only then disconnect the AC in/AC out jumper? But if have grid AC input then add jumper? If have grid AC input remove ground going to water main (grid is my ground) and if off grid I leave ground on water main (no grid to provide ground)?
 

timselectric

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The jumpers only purpose is to carry the N/G bond from your main panel to your loads panel. If you have no AC input, it's not necessary.

Grounding should be the same no matter what you do. The existing grounding system is the grounding system for everything.
 

MT off grid

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The jumpers only purpose is to carry the N/G bond from your main panel to your loads panel. If you have no AC input, it's not necessary.



Grounding should be the same no matter what you do. The existing grounding system is the grounding system for everything.
 

MT off grid

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Oh, I thought that if I had the inverters connected to my house panel which includes ground I would need to disconnect the ground to the water main so I wouldn't get a ground loop. So I only use jumpers if connected to house panel for AC input into inverters?
 

timselectric

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One ground conductor between systems.

The neutral jumper connects input neutral to output neutral. If you have no input, you don't need a jumper.
 

MT off grid

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Would be nice of growatt too care of all of that internally instead of having to do it manually, I would think that if I have AC input the growatt should figure out the rest
 

timselectric

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Every situation is different. It's hard to make a one size fits all. But yes, they could definitely have better manuals.
 
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