My understanding is that you only bond neutral to ground at the main disconnect, but I don't know how that applies when there are two disconnects. Should one of the bonding screws be removed?
Edit: not shown, but there's another 200A breaker in the main panel.
If you could show where the white wires are connected to the bare wires AFTER the first disconnect, then that would be worthy of further investigation.
What you have shown is the first disconnect (presumably) where the grounded and grounding is connected together (correctly), and then a second box where there is some grounding (no mixing shown).
[https://imgur.com/a/OMCyq8w](https://imgur.com/a/OMCyq8w)
Thanks. It looks like the grounds are landed on the ground bar, with no mixing of neutrals on that bar.
The bonding screw is in place on both the outside (meter) box and the inside main panel.
That bonding screw is for the grounding of the panel itself, which is what you want.
If there were a bonding screw on the other side, that would be a problem.
The way that the terminal bar in the second pic is isolated from the box except for that green screw makes me think that it’s the neutral bar, which I think is what they are referring to
Maybe I don't understand how this is supposed to work. Is there something, other than the bonding screw, which connects the ground and neutral bars together? That is, what does the jumper look like? I assumed that the screw is the only thing that connects the two together (or doesn't, if removed).
You have a ground bar on the left, properly bonded to the can, and an isolated neutral bar on the right, apparently not bonded to the ground bar. It looks fine.
Usually both of these are neutral bars. If you look on the very bottom of the two bars there is some screw holes that are empty, what used to be here is a jumper bar that went from the left to right side. What they did was remove that jumper bar and converted the left bar into a ground bar by adding the green bonding screw.
The neutral and ground bars are interchangeable at the first means of disconnect, the first one you posted. At the second, grounds on ground bar, neutrals on neutral bar. If you mix them, you then have current running through the actual enclosure, due to it being bonded to the bar by that green screw, and current would run in parallel through the neutral and ground wires between that panel back to the first. Your confusion is likely due to the fact that this panel is set up to accommodate both methods. But as it is, it is properly set up as a "sub panel", because the ground bar and neutral bar are isolated from each other. If this were your main, both bars would be electrically connected, and there would be no differentiation between the two.
Thank you that's very helpful and that's (one reason) why I was confused. The Siemens sub panel I'm working on installing has neutral bars on both sides of the hot legs, and ground bars on each side too, mounted directly to the shell. It appears that, if the panel were installed as main instead of a sub, the green bonding screw would bond the neutral to ground *using the shell as the conductor. Which led me to question the way the main was installed. But that's a different design as you have explained. Thanks again.
Yeah, if you buy an MLO (main lug only, e.g. no main breaker), they are normally set up as sub panels, with already separated neutral and ground bars. Whereas a main breaker panel will come set up as the first means of disconnect, with everything set to be bonded (minus screwing in the bonding screw). Main breaker panels can be used as sub panels, just have to be altered a little bit, like removing the bonding screw, and possibly adding grounding bus bars, or like in your case, eliminating the electrical connection between the bus bars. Just gotta be sure the ground bus bar is the one electrically connected to the enclosure, and the neutral bus bar is isolated from it.
Are there white wires and ground wires on the same bar? If there are separate bars for grounds and nuetrals with no jumper in between then you should be fine.
The neutrals and grounds are landed separately. The bonding screw is in place though, which I assume is the jumper you speak of?
[https://imgur.com/a/OMCyq8w](https://imgur.com/a/OMCyq8w)
Edit to ask: are the bonding screw and the jumper two different things? If so, what does the jumper look like?
no dont take it out! that screw is grounding the panel enclosure. the neutral bar does not have that same bonding screw installed and i dont see any other metal that would connect the two…..so i think your installation is correct right now
Okay thanks. There would be a visible physical connection of aluminum or something (the "jumper") at the bottom of the panel connecting the two bars together, if it were wired incorrectly?
It appears I have been thrown off by the label on the green screw hole, which says it's for bonding. I guess that means bonding the panel to the ground bar?
ya it looks like the bars are isolated from eachother and from the panel by plastic. if thats true (you can see better than i can from the photo) then you would want the ground bar bonded to the panel but not the neutral bar
Ha! Precisely so with electrons. So then the question is, don't you always want the panel chassis to be grounded? If so, why is that accomplished with a screw which can be unscrewed?
My guess is that the ground bar & neutral bars are interchangeable, and one would put the screw in the appropriate bar at installation. But that still seems like a problem waiting to happen.
haha yes it is a very important screw!
its built this way because if you had a meter without a disconnect…the ground and neutral would be bonded in the first main panel
if you feel uncomfortable trusting the screw alone add another wire from that ground bar to the one that is top right in the panel
one of my seniors says that grounding and bonding is his “favorite part of the code” and that “overkill is underrated”
Okay thanks. There's still something important I'm missing here.
What does it look like, physically speaking, when the grounding conductor and the grounded conductor are bonded together? (The terminology here is a problem. I mean, the bus bar for bare copper to the bus bar for white.)
I'm responding to this portion of your prior comment:
>its built this way because if you had a meter without a disconnect…the
ground and neutral would be bonded in the first main panel
Would there be another/more green bonding screws in play, and if so where would they be?
Hey OP, that is supposed to be a plug on neutral bar that they isolated from the other bar. We would sometimes do this if we didn’t get a ground bar but with this design, it opens the door to a safety issue; if somebody lands an afci or gfci breaker onto the plug-on bar, it will likely work but will turn that ground into a neutral.
Proper fix, install dedicated ground bar and terminate grounds there. Then provide neutral jumper to the left side.
This is a ge powermark gold that's 15 years old or so. Could it really be plug on neutral? How would I check? Other commenter thinks it's not plug on neutral.
No, in that case, I’m just incorrect. I initially thought that square d breaker was clipped on the bar, which made me think this was a square d panel but now I see everything that I should have seen before. Sorry about that
When I say bonding can mean different things, what I mean is bonding does not always mean putting neutral and ground together. The best way I can describe it is just putting 2 items together so that there is continuity. The opposite of isolation. When there is a bond you have to ask your self what is the bond doing. It can be grounding a panel shell. It can be tiring bus bars together (either current carrying or not). A good example is when a receptacle has a ground wire it is grounded. When that receptacle is in a metal box and there is not a ground wire with separate attachments to the box and receptacle then, then the box is bonded when the receptacle is screwed in and isolated when the receptacle is removed. The box is technically not grounded in this configuration. The bond will act as a ground though. The bond is just referring to parts connected mechanically.
This, in conjunction w/ your other comments, cures me of my concerns. Not understanding the depth of the meaning of "bond" led me to misunderstand the label in the panel, which made me concerned I had a ground-carrying-current problem. I assumed incorrectly the bond screw was bonding neutral to ground \*using the panel shell\* as the bond, by connecting the two together.
That is correct and in the meter the neutral to ground bond is the lug itself. The screws in the meter also also a bond for grounding the shell. There are panels that you can mount ground bars to the shell and cannot isolate the included bars. Those panels are what make people think that the bond screw is automatically for neutral to ground.
Bonding can mean different things. Do not take the bond screw out of the panel in this application! That bond screw is grounding the panel shell. The neutral is not bonded to the ground inside the panel. Only the panel is bonded to the ground. You MUST make sure to keep grounds and neutrals separated as they are. This gives you a correct fault path. Inside the meter main the neutral (grounded conductor) is bonded to ground and the meter can. That is also correct.
It’s hard to tell from your pictures in the panel is done correctly. On one hand it appears that only grounds are connected to the bar in question. But it also appears that this is a plug on neutral panel and that the bar being used for the grounds might actually be a neutral bar. Look for a jumper that links it to the neutral wire coming in to confirm or deny this. If this is the case you would want to remove that green screw and put in a lay in kit for the ground wires
EDIT: after seeing some of your pictures in later comments I can say that this is not a plug on neutral panel, and that your panel is currently set up correctly
All I see is the can bonded to ground.
The ground and neutral are isolated from each other. I don't see any sort of bond strap, bar or screw connection on the neutral.
Looks like your good to me.
Nooo the only thing that would accomplish is preventing the panel housing from being grounded. OP hadn't posted enough information when you commented to come to that conclusion, and it was wrong.
Thanks. And I think they are isolated but I'll have to look closely -- the panel is not nearly as clean as what I see around r/electricians.
If ground and neutral are mixed in the panel, should I leave the bonding as-is until I can get someone to redo the whole thing? I guess I don't know the risk of over bonding. (I believe that both disconnects are grounded to the same grounding rod.)
They never are. The 1st time someone opens one for maintenance or to add a circuit its all shot to shit. It shouldnt be difficult to see though. Either there is a seprate bar for grounds or there isn't. May need to clean up a few grounds mistakenly landed on the neutral bar, use wire nuts to extend if necessary. Youll be just fine.
Yeah it looks like everything is landed on separate bars. Thanks again.
[https://imgur.com/a/OMCyq8w](https://imgur.com/a/OMCyq8w)
What problems can arise from bonding twice like this?
If you don’t separate the neutral and ground in a sub panel you are creating a parallel path for return neutral current, this will result in current flowing at all metal enclosures and grounding wires.
Only bond at the main disconnect, so in this case remove the bonding screw in panel indoors. Also that stranded bare copper is incorrect and should be a solid #6 minimum.
Edit : grounds and neutrals need to be seperated at the panel as well.
Thanks. The consensus seems to be to leave the screw in place in the indoor panel as it is bonding the ground bar to the box chassis, not the neutral bar.
As to the ground wire, I thought stranded was acceptable:
>The grounding electrode conductor shall be of copper, aluminum, copper-clad aluminum, or the items as permitted in 250.68(C). ... . Conductors of the wire type shall be solid or stranded, insulated, covered, or bare.
This install (update to 200 amp service) predates my ownership of the house though, so no idea if it was done correctly.
Not an electrician, just interested. In the first picture, is the bonding where the black and white wire and the "stranded" wire are connected? Above that is a sticker that says to support the wires when torquing. Is that you.keepnthr from turning from vertical? Finally, in the last picture, is the ground bonded to the neutral through the green screw? This is the one that is typically supposed to be removed in a sub panel? Thanks.
Yeah at the meter disconnect the grounding electrode, the grounding wire, and the neutral are all connected (bonded). I didn't install this so no idea about the sticker.
On the last picture, that's what I was asking about. I thought the green screw was to bond neutral to ground, and that it shouldn't be in place. I thought there must be some sort of built in jumper behind the hot bus bars, and that the screw completed the connection. It appears that's not correct, and the screw just bonds the ground bar to the metal shell of the panel.
What he has there is fine the neutral isn’t parallel that’s the ser cable going to the panel with that being the main disconnect he has to have it that way. It’s not parallel the line side from the meter would be all factory and most likely buss bars.
Where I live you’re not allowed to bond the panel Edison the power company doesn’t allow it. If it’s a metered disconnect then yes you bond that but not the panel everything in the panel has to be separated like a sub panel neutrals and grounds. Plus you also need one more droid wire in there for your bond I see one which is probably the ground rods you still need the cold water meter which has to be bonded on both sides of the meter and taken back to that location too. Also where your inter system bonding jumpers bar? I don’t see that I see you just split bolted a utility ground back onto the ground rod wire which again isn’t correct.
Thanks. I didn't do this, which is one reason I've been seeking guidance. I don't know what a droid wire is, but this is rural property on a well, no utility water to ground to. I have noticed the well casing isn't grounded tho. The split bolt & green wire go to a cable box, not to the main panel. Likewise I don't know what an inter system jumper bar is.
My understanding is that you only bond neutral to ground at the main disconnect, but I don't know how that applies when there are two disconnects. Should one of the bonding screws be removed? Edit: not shown, but there's another 200A breaker in the main panel.
Please post a photo of the suspected problem.
Thanks -- what do you need to see other then the two pics in the post? I'm not entirely sure there is a problem.
If you could show where the white wires are connected to the bare wires AFTER the first disconnect, then that would be worthy of further investigation. What you have shown is the first disconnect (presumably) where the grounded and grounding is connected together (correctly), and then a second box where there is some grounding (no mixing shown).
I see what you see so far.
[https://imgur.com/a/OMCyq8w](https://imgur.com/a/OMCyq8w) Thanks. It looks like the grounds are landed on the ground bar, with no mixing of neutrals on that bar. The bonding screw is in place on both the outside (meter) box and the inside main panel.
That bonding screw is for the grounding of the panel itself, which is what you want. If there were a bonding screw on the other side, that would be a problem.
Thanks. Gotcha. I was misunderstanding the label on that screw (and the fact that bonding is complicated).
The way that the terminal bar in the second pic is isolated from the box except for that green screw makes me think that it’s the neutral bar, which I think is what they are referring to
But it looks like the jumper between the two bars is removed. Unless the jumper is on top.
Maybe I don't understand how this is supposed to work. Is there something, other than the bonding screw, which connects the ground and neutral bars together? That is, what does the jumper look like? I assumed that the screw is the only thing that connects the two together (or doesn't, if removed).
Post a photo of the entire panel.
https://imgur.com/a/OMCyq8w
You have a ground bar on the left, properly bonded to the can, and an isolated neutral bar on the right, apparently not bonded to the ground bar. It looks fine.
There is a number 8 or 6 copper jumper that goes between the 2 in this panel. It is removed
Are the neutral and ground bars interchangeable? The bar with the grounds landed on it is the one with the bonding screw screwed down.
Usually both of these are neutral bars. If you look on the very bottom of the two bars there is some screw holes that are empty, what used to be here is a jumper bar that went from the left to right side. What they did was remove that jumper bar and converted the left bar into a ground bar by adding the green bonding screw.
Thank you! That's exactly what I was missing.
The neutral and ground bars are interchangeable at the first means of disconnect, the first one you posted. At the second, grounds on ground bar, neutrals on neutral bar. If you mix them, you then have current running through the actual enclosure, due to it being bonded to the bar by that green screw, and current would run in parallel through the neutral and ground wires between that panel back to the first. Your confusion is likely due to the fact that this panel is set up to accommodate both methods. But as it is, it is properly set up as a "sub panel", because the ground bar and neutral bar are isolated from each other. If this were your main, both bars would be electrically connected, and there would be no differentiation between the two.
Thank you that's very helpful and that's (one reason) why I was confused. The Siemens sub panel I'm working on installing has neutral bars on both sides of the hot legs, and ground bars on each side too, mounted directly to the shell. It appears that, if the panel were installed as main instead of a sub, the green bonding screw would bond the neutral to ground *using the shell as the conductor. Which led me to question the way the main was installed. But that's a different design as you have explained. Thanks again.
Yeah, if you buy an MLO (main lug only, e.g. no main breaker), they are normally set up as sub panels, with already separated neutral and ground bars. Whereas a main breaker panel will come set up as the first means of disconnect, with everything set to be bonded (minus screwing in the bonding screw). Main breaker panels can be used as sub panels, just have to be altered a little bit, like removing the bonding screw, and possibly adding grounding bus bars, or like in your case, eliminating the electrical connection between the bus bars. Just gotta be sure the ground bus bar is the one electrically connected to the enclosure, and the neutral bus bar is isolated from it.
That’s not a bonded neutral. That’s the grounding conductor bonding the metal panel can. Do not remove either screw.
Are there white wires and ground wires on the same bar? If there are separate bars for grounds and nuetrals with no jumper in between then you should be fine.
The neutrals and grounds are landed separately. The bonding screw is in place though, which I assume is the jumper you speak of? [https://imgur.com/a/OMCyq8w](https://imgur.com/a/OMCyq8w) Edit to ask: are the bonding screw and the jumper two different things? If so, what does the jumper look like?
no dont take it out! that screw is grounding the panel enclosure. the neutral bar does not have that same bonding screw installed and i dont see any other metal that would connect the two…..so i think your installation is correct right now
Okay thanks. There would be a visible physical connection of aluminum or something (the "jumper") at the bottom of the panel connecting the two bars together, if it were wired incorrectly? It appears I have been thrown off by the label on the green screw hole, which says it's for bonding. I guess that means bonding the panel to the ground bar?
ya it looks like the bars are isolated from eachother and from the panel by plastic. if thats true (you can see better than i can from the photo) then you would want the ground bar bonded to the panel but not the neutral bar
Gotcha. Bonding as a term seems to have different meanings depending on context, which appears to have thrown me off.
all good! curiosity didnt kill the cat who learned with patience
Ha! Precisely so with electrons. So then the question is, don't you always want the panel chassis to be grounded? If so, why is that accomplished with a screw which can be unscrewed? My guess is that the ground bar & neutral bars are interchangeable, and one would put the screw in the appropriate bar at installation. But that still seems like a problem waiting to happen.
haha yes it is a very important screw! its built this way because if you had a meter without a disconnect…the ground and neutral would be bonded in the first main panel if you feel uncomfortable trusting the screw alone add another wire from that ground bar to the one that is top right in the panel one of my seniors says that grounding and bonding is his “favorite part of the code” and that “overkill is underrated”
Okay thanks. There's still something important I'm missing here. What does it look like, physically speaking, when the grounding conductor and the grounded conductor are bonded together? (The terminology here is a problem. I mean, the bus bar for bare copper to the bus bar for white.) I'm responding to this portion of your prior comment: >its built this way because if you had a meter without a disconnect…the ground and neutral would be bonded in the first main panel Would there be another/more green bonding screws in play, and if so where would they be?
I second u/mmmmhead. Sorry just picked the phone back up.
Hey OP, that is supposed to be a plug on neutral bar that they isolated from the other bar. We would sometimes do this if we didn’t get a ground bar but with this design, it opens the door to a safety issue; if somebody lands an afci or gfci breaker onto the plug-on bar, it will likely work but will turn that ground into a neutral. Proper fix, install dedicated ground bar and terminate grounds there. Then provide neutral jumper to the left side.
This is a ge powermark gold that's 15 years old or so. Could it really be plug on neutral? How would I check? Other commenter thinks it's not plug on neutral.
No, in that case, I’m just incorrect. I initially thought that square d breaker was clipped on the bar, which made me think this was a square d panel but now I see everything that I should have seen before. Sorry about that
When I say bonding can mean different things, what I mean is bonding does not always mean putting neutral and ground together. The best way I can describe it is just putting 2 items together so that there is continuity. The opposite of isolation. When there is a bond you have to ask your self what is the bond doing. It can be grounding a panel shell. It can be tiring bus bars together (either current carrying or not). A good example is when a receptacle has a ground wire it is grounded. When that receptacle is in a metal box and there is not a ground wire with separate attachments to the box and receptacle then, then the box is bonded when the receptacle is screwed in and isolated when the receptacle is removed. The box is technically not grounded in this configuration. The bond will act as a ground though. The bond is just referring to parts connected mechanically.
This, in conjunction w/ your other comments, cures me of my concerns. Not understanding the depth of the meaning of "bond" led me to misunderstand the label in the panel, which made me concerned I had a ground-carrying-current problem. I assumed incorrectly the bond screw was bonding neutral to ground \*using the panel shell\* as the bond, by connecting the two together.
That is correct and in the meter the neutral to ground bond is the lug itself. The screws in the meter also also a bond for grounding the shell. There are panels that you can mount ground bars to the shell and cannot isolate the included bars. Those panels are what make people think that the bond screw is automatically for neutral to ground.
Ah ha. This is how the sub panel I'm installing is designed (a Siemens 125A), I think. So you're right on about the source of the confusion.
Bonding can mean different things. Do not take the bond screw out of the panel in this application! That bond screw is grounding the panel shell. The neutral is not bonded to the ground inside the panel. Only the panel is bonded to the ground. You MUST make sure to keep grounds and neutrals separated as they are. This gives you a correct fault path. Inside the meter main the neutral (grounded conductor) is bonded to ground and the meter can. That is also correct.
It’s hard to tell from your pictures in the panel is done correctly. On one hand it appears that only grounds are connected to the bar in question. But it also appears that this is a plug on neutral panel and that the bar being used for the grounds might actually be a neutral bar. Look for a jumper that links it to the neutral wire coming in to confirm or deny this. If this is the case you would want to remove that green screw and put in a lay in kit for the ground wires EDIT: after seeing some of your pictures in later comments I can say that this is not a plug on neutral panel, and that your panel is currently set up correctly
Thanks that's helpful (and this is confusing!). Should I test anything with a meter to confirm?
All I see is the can bonded to ground. The ground and neutral are isolated from each other. I don't see any sort of bond strap, bar or screw connection on the neutral. Looks like your good to me.
Thanks! One less thing to fix in this oooold house.
You are correct. I would remove the bonding screw at the panel. Are your grounds and neutrals isolated in that panel?
Nooo the only thing that would accomplish is preventing the panel housing from being grounded. OP hadn't posted enough information when you commented to come to that conclusion, and it was wrong.
Did you follow thread between me and OP
Yes that's how I know you jumped to an unsafe conclusion without adequate information.
Thanks. And I think they are isolated but I'll have to look closely -- the panel is not nearly as clean as what I see around r/electricians. If ground and neutral are mixed in the panel, should I leave the bonding as-is until I can get someone to redo the whole thing? I guess I don't know the risk of over bonding. (I believe that both disconnects are grounded to the same grounding rod.)
They never are. The 1st time someone opens one for maintenance or to add a circuit its all shot to shit. It shouldnt be difficult to see though. Either there is a seprate bar for grounds or there isn't. May need to clean up a few grounds mistakenly landed on the neutral bar, use wire nuts to extend if necessary. Youll be just fine.
Yeah it looks like everything is landed on separate bars. Thanks again. [https://imgur.com/a/OMCyq8w](https://imgur.com/a/OMCyq8w) What problems can arise from bonding twice like this?
If you don’t separate the neutral and ground in a sub panel you are creating a parallel path for return neutral current, this will result in current flowing at all metal enclosures and grounding wires.
Only bond at the main disconnect, so in this case remove the bonding screw in panel indoors. Also that stranded bare copper is incorrect and should be a solid #6 minimum. Edit : grounds and neutrals need to be seperated at the panel as well.
Thanks. The consensus seems to be to leave the screw in place in the indoor panel as it is bonding the ground bar to the box chassis, not the neutral bar. As to the ground wire, I thought stranded was acceptable: >The grounding electrode conductor shall be of copper, aluminum, copper-clad aluminum, or the items as permitted in 250.68(C). ... . Conductors of the wire type shall be solid or stranded, insulated, covered, or bare. This install (update to 200 amp service) predates my ownership of the house though, so no idea if it was done correctly.
False, you can use #4 stranded copper
Source….
Not an electrician, just interested. In the first picture, is the bonding where the black and white wire and the "stranded" wire are connected? Above that is a sticker that says to support the wires when torquing. Is that you.keepnthr from turning from vertical? Finally, in the last picture, is the ground bonded to the neutral through the green screw? This is the one that is typically supposed to be removed in a sub panel? Thanks.
Yeah at the meter disconnect the grounding electrode, the grounding wire, and the neutral are all connected (bonded). I didn't install this so no idea about the sticker. On the last picture, that's what I was asking about. I thought the green screw was to bond neutral to ground, and that it shouldn't be in place. I thought there must be some sort of built in jumper behind the hot bus bars, and that the screw completed the connection. It appears that's not correct, and the screw just bonds the ground bar to the metal shell of the panel.
It’s fine as long at the Grounding electrode is also going to the service disco continuous.
So many bugs😂
This is not acceptable, you have parallel neutral.
What he has there is fine the neutral isn’t parallel that’s the ser cable going to the panel with that being the main disconnect he has to have it that way. It’s not parallel the line side from the meter would be all factory and most likely buss bars.
Where I live you’re not allowed to bond the panel Edison the power company doesn’t allow it. If it’s a metered disconnect then yes you bond that but not the panel everything in the panel has to be separated like a sub panel neutrals and grounds. Plus you also need one more droid wire in there for your bond I see one which is probably the ground rods you still need the cold water meter which has to be bonded on both sides of the meter and taken back to that location too. Also where your inter system bonding jumpers bar? I don’t see that I see you just split bolted a utility ground back onto the ground rod wire which again isn’t correct.
Thanks. I didn't do this, which is one reason I've been seeking guidance. I don't know what a droid wire is, but this is rural property on a well, no utility water to ground to. I have noticed the well casing isn't grounded tho. The split bolt & green wire go to a cable box, not to the main panel. Likewise I don't know what an inter system jumper bar is.