GE Panel Bonding Screw (subpanel)

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mijoni

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Central CT
First off let me say hi to everyone. I'm an electrical apprentice working in the northeast us doing primarily residential work and some light commercial.

I have a question I'd like to ask that would help alleviate some doubts I have regarding proper bonding methods of feeder-supplied panels (subpanels) in residential situations, strictly single-phase 240/120v.

Our company has installed lots of resi subpanels in varying situations such as attached structures, remote etc., and if they are new subpanels, they are always fed via a 4-wire feeder regardless of their location. My boss prefers GE products and that is what we use 99% of the time. SOP for our GE subpanels is to pull a 4-wire feeder, remove the strap between the right and left neutral/ground buses and use one side solely for landing neutrals, the other for landing grounds.

My question is rather simple, and your input would help end an ongoing "peeve" I've had with the boss since the very first GE residential subpanel we did.

Can the green bonding screw that is supplied with GE panels be safely used to bond the panel case to the (separated) ground bus? Or should another method be used? He says "no", do not bond -either- bus in any fashion to the panel case. I feel this is wrong because on the GE panels we use, the ground/neutral buses sit in an insulated plastic retainer which does not have any electrical connection to the case itself.

My opinion (correct me if I'm wrong, that's what I'm here asking for) is that since the green bonding screw is rated for use to bond a neutral to the case, why not use it for the ground bus in a subpanel? Keep in mind the ground/neutral buses would be separated, and the green bonding screw would only be installed on the ground bus.

So far no inspector has said anything, and I'm not about to initiate a conversation with one regarding this :)

Thank you and highest regards to all.
 
Same

Same

We do the same as Dennis. That green screw is provided by the manufacturer for that purpose. If you don't use it on the "ground" bar, you have not bonded the case.
 
GE Panel Bonding Screw (sub panel)

GE Panel Bonding Screw (sub panel)

The ground bar must be bonded to the panel enclosure,the grounded conductor should be isolated from the enclosure.

Also if using the 2008 NEC the 25 ohm rule applies, and 2 ground rods must be used if they are providing the ges.
 
electrician of 30 yrs. of quality workmanship!!!!!!!!

electrician of 30 yrs. of quality workmanship!!!!!!!!

Every sub -panel (must) be isloated from the can ....The grounding buss must screwed to the can w/ a machine threaded screw not a sheet metal screw, it is stated in the N.E.C........From sub panel to sub panel on and on to last sub thats being fed nuetral and ground are set up just the same......... rhetorical????????????????have fun;) ;) :roll:
 
Removing the jumper between the bars just violated the UL listing. Siemens has a plastic jumper that you can buy that keeps the listing valid. I don't know if GE has the same.
 
I don't know why you would remove the jumper between the two in the first place. IMO a separate ground bar should be provided although it's not likely required by code. I believe that some panelboards do say in their instructions that the jumper can be removed for the purpose of separating the EGC's from the neutrals.
 
hillbilly1 said:
Removing the jumper between the bars just violated the UL listing. Siemens has a plastic jumper that you can buy that keeps the listing valid. I don't know if GE has the same.

I don't know if Ge makes one or not but I just don't see the need for it. The bars are very solidly fixed to the panel.
 
Thanks to all for your replies.
The boss's argument for not using the green screw relates to the specific wording on the plastic bag the screw is shipped in:

"Bonding Screw: When it is required to bond box to neutral use this screw. Insert through hole in neutral, and thread screw into hole in the box"

He says since the grounding bus isn't mentioned, it's not for use there. I say, since the word "Bonding" is mentioned, it should be used for just that, although on the grounding bus instead of the neutral.

I'll never win the argument anyway since he still signs my checks :)

Now I'm a bit worried about the UL listing issue hillbilly1 brought up. I think I'll fire off an email to GE and try to see what their response is.

I've seen a lot (and I mean hundreds) of GE subpanels with the strap removed - seems to be a very common thing to do in this area. I know that seeing so many installed in this manner doesn't make it right, but no one I've ever talked to in the trade has seemed to question it. Now's the first time I'm even thinking about it, which is a good thing. Thanks hillbilly!

And yes - to respond to some points brought up: we do drive ground rod pairs for remote structure subpanels and we separate the neutral/grounding buses.

Thanks again all!
 
hillbilly1 said:
Removing the jumper between the bars just violated the UL listing.
I guess that would depend on the specific GE product line used.
The GE PowerMark Gold? Single Phase(USA) ALLOWS the buss to be seperated:

8. Optional wiring of neutral and ground
The neutral crossbar may be removed to provide optional neutral and ground wiring as follows:


161258_singlephaseUSA.gif


Does this look like what you have there mijoni?

If so (from the same GE documentation):
7. Wire main, neutral, and equipment ground.
Refer to rating label inside equipment for proper tightening torque. Wire neutral and equipment ground only in direction indicated by arrows. If required, ground and bond neutral to box using screw provided.
Considering that the grounded buss is isolated from the enclosure (requiring the use of the screw at times), it stands to reason that merely breaking the connection between sides will not alleviate the lack of a main bonding jumper.
 
mijoni said:
My opinion (correct me if I'm wrong, that's what I'm here asking for) is that since the green bonding screw is rated for use to bond a neutral to the case, why not use it for the ground bus in a subpanel? Keep in mind the ground/neutral buses would be separated, and the green bonding screw would only be installed on the ground bus.
You are correct. Tell the boss that, yes, the screw is used to bond the panel to the neutral when used as service equipment. In your case, the panel should not, and is not being bonded to the neutral.

However, the EGC's still should be, and the screw is perfect for the job. Your boss is leaving the cans floating, a clear violation. The EGC's and panel should always be bonded, whether or not the neutral is.
 
celtic said:
I guess that would depend on the specific GE product line used.
The GE PowerMark Gold? Single Phase(USA) ALLOWS the buss to be seperated:


161258_singlephaseUSA.gif


Does this look like what you have there mijoni?

If so (from the same GE documentation):

Considering that the grounded buss is isolated from the enclosure (requiring the use of the screw at times), it stands to reason that merely breaking the connection between sides will not alleviate the lack of a main bonding jumper.

Those panels are what we keep in stock and use daily, in both MLO and MB style, in different load ratings (60-200A). Yes.

You just enabled me to sleep tonight. :) I opened a new panel we have, found the installation sheet and verified that removing the crossbar is indeed ok to do. Paragraph 8, just as you posted.

I don't know why my boss is so hard headed about the bonding issue. I'll point him here so he can read this thread for himself.

Thank you.
 
LarryFine said:
You are correct. Tell the boss that, yes, the screw is used to bond the panel to the neutral when used as service equipment. In your case, the panel should not, and is not being bonded to the neutral.

However, the EGC's still should be, and the screw is perfect for the job. Your boss is leaving the cans floating, a clear violation. The EGC's and panel should always be bonded, whether or not the neutral is.

This is exactly what I suspected, thanks for spelling it out for me. Luckily I can fix any panel installed 'floating' very quickly the next time I'm servicing one - I have a rather large collection of green screws. :rolleyes:

Thank you.
 
celtic said:
Considering that the grounded buss is isolated from the enclosure (requiring the use of the screw at times), it stands to reason that merely breaking the connection between sides will not alleviate the lack of a main bonding jumper.
Actually, removing the bar between the neutrals and the EGC's is creating the (desirable in this case) lack of a main bonding jumper.

The main bonding jumper is in the main disconnect enclosure.
 
mijoni said:
First off let me say hi to everyone. I'm an electrical apprentice working in the northeast us doing primarily residential work and some light commercial.

I have a question I'd like to ask that would help alleviate some doubts I have regarding proper bonding methods of feeder-supplied panels (subpanels) in residential situations, strictly single-phase 240/120v.

Our company has installed lots of resi subpanels in varying situations such as attached structures, remote etc., and if they are new subpanels, they are always fed via a 4-wire feeder regardless of their location. My boss prefers GE products and that is what we use 99% of the time. SOP for our GE subpanels is to pull a 4-wire feeder, remove the strap between the right and left neutral/ground buses and use one side solely for landing neutrals, the other for landing grounds.

My question is rather simple, and your input would help end an ongoing "peeve" I've had with the boss since the very first GE residential subpanel we did.

Can the green bonding screw that is supplied with GE panels be safely used to bond the panel case to the (separated) ground bus? Or should another method be used? He says "no", do not bond -either- bus in any fashion to the panel case. I feel this is wrong because on the GE panels we use, the ground/neutral buses sit in an insulated plastic retainer which does not have any electrical connection to the case itself.

My opinion (correct me if I'm wrong, that's what I'm here asking for) is that since the green bonding screw is rated for use to bond a neutral to the case, why not use it for the ground bus in a subpanel? Keep in mind the ground/neutral buses would be separated, and the green bonding screw would only be installed on the ground bus.

So far no inspector has said anything, and I'm not about to initiate a conversation with one regarding this :)

Thank you and highest regards to all.

Throw your boss's kliens in the nearest canal and hand him a broom.
If he tells you that "he has forgot more than you know" tell him the green screw must have been been one of the things he forgot!:grin:
 
jrannis said:
....If he tells you that "he has forgot more than you know" tell him the green screw must have been been one of the things he forgot!:grin:

Funny ,..thanks for the chuckle...

I don't understand why he thinks that the wording on the package relieves him from bonding the enclosure to the EGC.??? Even if it did prevent that particular screw from being used in such a way the enclosure requires a connection to the EGC.

Does he know that equipment grounding bar is floating??

does he not view the enclosure as equipment needing bonding??
 
M. D. said:
Funny ,..thanks for the chuckle...

I don't understand why he thinks that the wording on the package relieves him from bonding the enclosure to the EGC.??? Even if it did prevent that particular screw from being used in such a way the enclosure requires a connection to the EGC.

Does he know that equipment grounding bar is floating??

does he not view the enclosure as equipment needing bonding??

I tried to explain to him that the case wasn't bonded, but he just replied with the "you're wrong. This is the way I've done it for years, we're done talking about it, now get back to work" type of attitude.

Matter of fact, I can't even get him to come here to view this thread, he's such a hard head old-schooler.

There is one point I'd like to bring up. When we do subpanels that are required to have ground rods driven at its location, the GEC from the new rods enters the case through a "twin screw" metal NM clamp, then is landed on the ground bar. I would think that although not 100% to code, the GEC is helping to bond the case via the NM clamp installed in the knockout. We use stricly bare copper for our grounding electrode conductor, typically stranded #4.

I know the correct way to bond the panels and it will be done from now on, on any job I have to work on, even if it means getting the boss mad.

Thanks guys and have a great weekend.
 
You don't need an NM conn for the GEC. There is a small hole in the bottom of all residential panels that is just the right size for the GEC to run thru. Just punch it out - no need to connect it to the case .
 
mijoni said:
the GEC from the new rods enters the case through a "twin screw" metal NM clamp, then is landed on the ground bar. I would think that although not 100% to code, the GEC is helping to bond the case via the NM clamp installed in the knockout. We use stricly bare copper for our grounding electrode conductor, typically stranded #4.


The NM connector is not listed to bond the GEC to the panel box. It's not even listed to fasten the EGC to the box. There is a listed fitting called the Kenny clamp that can be used for this purpose but is not required by code. Using Dennis' method (small KO) is code compliant.


kennyclampinstalledcloseup.jpg
 
Question ,...what would happen, ...in a panel wired by the boss,.. to that connector on the # 4 should one the ungrounded feeder conductors fault to the enclouser ??? or better yet if it had been passed through that little K.O.

Melt,.. spark and sputter ?? or safey carry the fault?? nothing at all ,..just sit
there with a high potential to harm ??
 
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