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Where do i need to bond neutral to ground?

medge

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Oct 4, 2022
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I have a shed near my cabin that house all of my solar components. In the shed, I have two sungold power TP6048 inverters that feed two 50 amp breakers. The main 100 amp breaker in the shed feeds the main breaker in the cabin. There is a ground rod at the shed, the cabin, and the panels. Right now the panel in the cabin is bonded to ground. Is that correct or should i bond the shed panel? or should I disconnect all the panel bonds?

I am working on hooking up a generator for back up power that the inverters will auto start when battery and solar power is low. Still trying to figure out how to connect the generator up but thats for another thread.
 
As far as I know there should only be 1 Neutral-Ground bond for the entire system. Sounds like that connection is made inside the cabin panel, if so everything should be good. Perhaps one of the forum electricians would suggest moving the Neutral-Ground bond to a different panel but as long as the neutral is shared by all the panels you mentioned that shouldn't be necessary.
 
I have a shed near my cabin that house all of my solar components. In the shed, I have two sungold power TP6048 inverters that feed two 50 amp breakers. The main 100 amp breaker in the shed feeds the main breaker in the cabin. There is a ground rod at the shed, the cabin, and the panels. Right now the panel in the cabin is bonded to ground. Is that correct or should i bond the shed panel? or should I disconnect all the panel bonds?

I am working on hooking up a generator for back up power that the inverters will auto start when battery and solar power is low. Still trying to figure out how to connect the generator up but thats for another thread.
1) 'There is a ground rod at the shed, the cabin, and the panels.' Are you saying that you have three Ground rods?
2) Do you also have Utility right now?
3) So the power from Solar or the Generator will be fed into the panel in the shed then it will be wired to the house, correct? if that is the case, if you bond the neutral and Safety ground at the panel in the house, it means there will be current flowing in the Safety Ground wire and the Neutral wires between the shed and the house which should not be, if you draw up the diagram then you can see the path of the current flow in the wires.
4) It looks to me that the panel in your shed where the power sources are connected to is the Main panel where you should bond the Neutral and Safety Ground, the panel in your house is the Sub panel which should not have Neutral and Safety Ground bonded. Neutral and Safety Ground should be bonded at one point only in the system and should be done as close to the power source, if you have more than one N-G bonded you will have Load current flow in the Safety Ground wire, Safety Ground wire is for carrying fault current so the breaker will trip, it is not for carrying Load current.
 
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1) 'There is a ground rod at the shed, the cabin, and the panels.' Are you saying that you have three Ground rods?
2) Do you also have Utility right now?
3) So the power from Solar or the Generator will be fed into the panel in the shed then it will be wired to the house, correct? if that is the case, if you bond the neutral and Safety ground at the panel in the house, it means there will be current flowing in the Safety Ground wire and the Neutral wires between the shed and the house which should not be, if you draw up the diagram then you can see the path of the current flow in the wires.
4) It looks to me that the panel in your shed where the power sources are connected to is the Main panel where you should bond the Neutral and Safety Ground, the panel in your house is the Sub panel which should not have Neutral and Safety Ground bonded. Neutral and Safety Ground should be bonded at one point only in the system and should be done as close to the power source, if you have more than one N-G bonded you will have Load current flow in the Safety Ground wire, Safety Ground wire is for carrying fault current so the breaker will trip, it is not for carrying Load current.
1.) yes. All three places. Only cabin is bonded at the moment.
2.) no utility available. Completely off the grid. Generator will only be ran if battery & solar cannot supply enough power to meet demand
3.) i am not sure if the generator should directly feed the inverters with inline breakers or if generator should feed the shed panel. Sun gold has been non responsive for weeks now. As far as current flow goes the neutral is confusing to me.
4.) i am thinking the same. If it is to be bonded it would need to be in the shed panel. Tho i have read alot of conflicting articles on different setups and inverters. Some say no bonding it required at all.
 
i am thinking the same. If it is to be bonded it would need to be in the shed panel. Tho i have read alot of conflicting articles on different setups and inverters. Some say no bonding it required at all.
Edit from earlier post. BM is correct, the Neutral-Ground Bond needs to be in the panel where power originates which in this case is the shed. I totally overlooked this detail. You do not want to create an alternate path for current that should be 100% on the neutral to partially flow on the ground. This of course refers to normal operating conditions. No current on the ground wire, unless there is a short circuit somewhere.
In summary:
1) Bonding is required because it completes the short circuit loop through the ground wire to neutral back to the source drawing a large current in the process which will trip the breaker and kill the dangerous circuit.
2) Bonding should be done in the Shed which is the source of power and the bond in the cabin should be removed.
 
BTW, when you have N-G bonding at more than on place the GFCI will trip when you have load connected because now the current on the Neutral and Line will not be equal because it now has two return paths back to the source, one in Neutral and another one on the Safety Ground.
 
Its not that easy of a question to answer in a solar hybrid power install. Do you have a generator? What sort of protection dos your inverters have? Are they GFCI? Arc Fault? etc.....
 
Its not that easy of a question to answer in a solar hybrid power install. Do you have a generator? What sort of protection dos your inverters have? Are they GFCI? Arc Fault? etc.....
Each of the inverters are hooked into their own 50 amp breaker in the shed panel. The inverters are sungold split phase 6000w TP6048.

The generator I am trying to connect is a Westinghouse 7500 with electric start. It has its own built in main breaker.
 
Each of the inverters are hooked into their own 50 amp breaker in the shed panel. The inverters are sungold split phase 6000w TP6048.

The generator I am trying to connect is a Westinghouse 7500 with electric start. It has its own built in main breaker.

If the generator has a floating neutral and your inverters have a floating neutral then I would bond in the panel at the house.

Ideally you would bond the neutral at the inverters and generator and leave the one in the panel floating.

The complications arise because of the different variations in all the different power sources you will be using, how they transfer etc. If your generator passes through your inverter...all that.
 
If the generator has a floating neutral and your inverters have a floating neutral then I would bond in the panel at the house.

Ideally you would bond the neutral at the inverters and generator and leave the one in the panel floating.

The complications arise because of the different variations in all the different power sources you will be using, how they transfer etc. If your generator passes through your inverter...all that.
My preference in this situation is to bond n to g at the main panel and put a sticker or tag on the panel to clearly identify that the panel has the bond.
I would then put a sticker or tag on each source to indicate that it is floating, especially if they are not hardwired.
My thought is main panels usually are bonded at install and usually have the neutrals and grounds all mixed together.
Also I prefer not rely on a relay to make the dynamic bond unless its necessary.
 
If the generator has a floating neutral and your inverters have a floating neutral then I would bond in the panel at the house.

Ideally you would bond the neutral at the inverters and generator and leave the one in the panel floating.

The complications arise because of the different variations in all the different power sources you will be using, how they transfer etc. If your generator passes through your inverter...all that.
How do you electrically test is they are floating? I am planning on hooking the gen into the ac in on the inverters.
 
My preference in this situation is to bond n to g at the main panel and put a sticker or tag on the panel to clearly identify that the panel has the bond.
I would then put a sticker or tag on each source to indicate that it is floating, especially if they are not hardwired.
My thought is main panels usually are bonded at install and usually have the neutrals and grounds all mixed together.
Also I prefer not rely on a relay to make the dynamic bond unless its necessary.
I agree with having a n-g bond in one of the panels. What can be hurt if I bond the shed panel whether the gen and or inverter are floating or not? My gut says bond the shed panel (closest to source ) & dis bond the house panel. Inverter relay would just be adding another bond in the same panel. Main priority is keeping the magic smoke in the inverters. Once the smoke is gone its gone…
 
This is correct.

The main originating power source is where the bond should be.
The generator should ONLY feed to the originating panel...
It definitely needs to be bonded.

I agree with having a n-g bond in one of the panels. What can be hurt if I bond the shed panel whether the gen and or inverter are floating or not? My gut says bond the shed panel (closest to source ) & dis bond the house panel. Inverter relay would just be adding another bond in the same panel. Main priority is keeping the magic smoke in the inverters. Once the smoke is gone its gone…
 
I agree with having a n-g bond in one of the panels. What can be hurt if I bond the shed panel whether the gen and or inverter are floating or not? My gut says bond the shed panel (closest to source ) & dis bond the house panel. Inverter relay would just be adding another bond in the same panel. Main priority is keeping the magic smoke in the inverters. Once the smoke is gone its gone…
There can only be one bond.
I'm guessing the shed panel is currently a sub-panel and the house panel is the main panel with n-g bond, confirm?
I'm hearing you say that you will make the shed panel the main panel with neutral-ground bond and the house panel will become subordinate.
That will likely mean re-landing the neutrals and grounds at the original main panel.
Where is/are the grounding electrode(s)?

BTW: I'm not an electrician just some random guy with opinions.
 
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What can be hurt if I bond the shed panel whether the gen and or inverter are floating or not?
To answer this more explicitly there must be a neutral ground bond for fault clearance and there can be no more than one neutral gound bond to avoid service current flowing on the ground wire.
 
Revised for emphasis.

Each structure's potential grounds (pipes, etc.) should be bonded, and you should also bond the 3 ground rods together.

From my signature:

I just watched that for the first time since the 80's about a month ago.
I mean The Highlander, that grounding guy is too intense.
 
This is correct.

The main originating power source is where the bond should be.
The generator should ONLY feed to the originating panel...
It definitely needs to be bonded.
There can only be one bond.
I'm guessing the shed panel is currently a sub-panel and the house panel is the main panel with n-g bond, confirm?
I'm hearing you say that you will make the shed panel the main panel with neutral-ground bond and the house panel will become subordinate.
That will likely mean re-landing the neutrals and grounds at the main panel.
Where is/are the grounding electrode(s)?

BTW: I'm not an electrician just some random guy with opinions.
When we purchased the cabin there was only the 1 panel in the cabin that had a generator connection. Due to space i built a shed to house the solar. In doing so i had to add a panel that would tie the inverters together and feed the existing panel in the cabin. As of right now the existing cabin panel is still bonded, but since it has become the sub panel it sounds like the bond needs to move to the new main panel in the shed.

There is a ground rod at the panels, shed, and cabin.

The generator will only feed the main panel thru the ac input on the inverters.
 
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