Double Tapping on the Neutral Bus Bar.

Reply

  #1  
Old 05-16-13, 06:37 PM
Member
Thread Starter
Join Date: Mar 2012
Posts: 11
Received 0 Votes on 0 Posts
Double Tapping on the Neutral Bus Bar.

OK. So I'm working with a sub panel (main break, and Ground/neutral bond are located outside near the meter). Its a GE 100A panel.

When I designed the circuits for this apartment I built an extra circuit for each room for potential A/C units. All told I have 17 circuits leaving this panel. The panel only has 12 slots, so I used a few of the Slim breakers.

Here's the problem. The Ground bus bar, and neutral bus bar only have 12 lug screws per bar. From what I researched the Equipment ground conductors can be doubled under the screws, but the neutral conductors can't according to the most current version of the NEC.

According my towns website they enforce the 2005 revision of the NEC which says nothing about double tapping.

To be on the safe side if I wanted to comply with the most current code what should I do? I can't find neutral bus bars ANYWHERE. Plenty of people talk about Neutral bus bar kits, but they don't seem to exist.

Any suggestions?

Pictures below.

Also, the empty spots are spoken for. I haven't run those cables yet.

Side note, for the record I think this code is BS. I think exceptions should exists depending on circuit load maybe. All of the reasons I've seen for this code seem to fall flat, Any thoughts?
 
Attached Images    
Sponsored Links
  #2  
Old 05-16-13, 06:54 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,257
Received 482 Votes on 452 Posts
Wait a minute.....this is a sub panel in your pictures ?

If that is correct then your ground wires should not be in the neutral bars. The bonding screw(s) that go thru the neutral bar into the chassis of the box should be removed.

Leave your existing neutral bars as they are for neutrals only and add a new ground bar. The new ground bar will come with its own screws that must be used. I see a ground wire coming in with your service cable but not connected to anything. That should go to the ground bar you will be adding.

On a second look it appears that the ground may be connected to the neutral bar..... that will need to be changed.
 
  #3  
Old 05-16-13, 07:14 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
Received 1 Vote on 1 Post
I think this code is BS. I think exceptions should exists depending on circuit load maybe. All of the reasons I've seen for this code seem to fall flat, Any thoughts?
I'll answer this first, because it's critically important. The requirement that there can only be one grounded conductor terminated under any screw on the neutral bus is not BS. An open neutral can and will create voltages in excess of 120 on every part of your system that it supplied. For that reason alone, it is critically important to take reasonable steps to insure that they aren't likely to come loose or, if they do, that the problem and be quickly spotted and corrected.

Its a GE 100A panel.
What model?

When I designed the circuits for this apartment I built an extra circuit for each room for potential A/C units. All told I have 17 circuits leaving this panel. The panel only has 12 slots, so I used a few of the Slim breakers.
Your panel may be designed to allow those in every location, or only in some. Read the label inside the panel door to determine which.

You may need a larger panel.

Here's the problem. The Ground bus bar, and neutral bus bar only have 12 lug screws per bar. From what I researched the Equipment ground conductors can be doubled under the screws,
Iff the two conductors are the same size. IOW, don't attempt to terminate one 14 AWG conductor and one 12 AWG conductor under the same screw.

the neutral conductors can't according to the most current version of the NEC.
Correct. See above. Right now I'm seeing 12-screw neutral bar with 9 neutrals terminated to it. What's the issue? Are all the circuits that you're feeding from this subpanel 120V hot-to-neutral circuits?

To be on the safe side if I wanted to comply with the most current code what should I do? I can't find neutral bus bars ANYWHERE. Plenty of people talk about Neutral bus bar kits, but they don't seem to exist. Any suggestions?
I've bought them by the dozen before - they're as common as dirt around here. Take the model number of your panel with you to the electrical supply house in your area that distributes GE equipment. They should have what you need.

In addition, if you post the model number of your panel here we can help you search for them.

Stuff you didn't ask about: Are the neutrals isolated from ground? Are the grounds bonded to each other and is the enclosure bonded to ground?
 
  #4  
Old 05-16-13, 07:34 PM
Member
Thread Starter
Join Date: Mar 2012
Posts: 11
Received 0 Votes on 0 Posts
Ahh.

The sub panel was installed by contractors a few years ago before they abandoned the renovation. They mounted the panel, and installed the main cable feed. I believe that the left side bar was intended to be used as the equipment ground right out of the box because even the brand new panels I was considering purchasing are set up with the right side isolated, and the left side bound to chassis with a screw. What you're suggesting is to add an equipment ground bar, and use the bar that's currently being used as equipment ground as another neutral bar by simply removing that bonding screw. How would you suggest I bind the the left and right bars together properly so they are both neutral?

Thank you for your reply btw!
 
  #5  
Old 05-16-13, 07:41 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
Received 1 Vote on 1 Post
How would you suggest I bind the the left and right bars together properly so they are both neutral?
With a bonding jumper. A piece of 3 AWG white wire terminated into two add-in lugs should do it.
 
  #6  
Old 05-16-13, 08:13 PM
Member
Thread Starter
Join Date: Mar 2012
Posts: 11
Received 0 Votes on 0 Posts
Thanks Again

Thanks again for the responses, you guys have been extremely helpful!

What model?
I believe the Model # is TLM1212CCU MOD 1. Not sure of "MOD 1" is part of the model #.

I've bought them by the dozen before - they're as common as dirt around here. Take the model number of your panel with you to the electrical supply house in your area that distributes GE equipment. They should have what you need.
Ill have to clarify, I've seen plenty of Bus bars at the store that are labeled "Equipment Ground" Specifically. My assumption was that they weren't intended to be used as Neutral ground bars. Until the suggestions I got here I hadn't even thought of using the current Equipment ground bar as the neutral and putting in a new equipment ground. With that said do you feel that is the best way to go Nashkat1?

Correct. See above. Right now I'm seeing 12-screw neutral bar with 9 neutrals terminated to it. What's the issue? Are all the circuits that you're feeding from this subpanel 120V hot-to-neutral circuits?
I have more circuits to add. Yes they are all Hot-to-Neutral. I will be adding two 240v circuits for an electric range and a Dryer.

Your panel may be designed to allow those in every location, or only in some. Read the label inside the panel door to determine which.
According to the label they are allowed in all locations. I lucked out there.

Stuff you didn't ask about: Are the neutrals isolated from ground? Are the grounds bonded to each other and is the enclosure bonded to ground?
Yes
Yes
and, yes.

They installed the main breaker outside right near the meter, and that is the only place where neutral and ground are bound.
 
  #7  
Old 05-16-13, 08:25 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,257
Received 482 Votes on 452 Posts
Technically if there is no buss bar connecting the left and right bars then that install is incorrect.

As it is right now....if there is no buss bar connecting the left and right bars together then you are getting your neutral thru the neutral bonding screws which was not intended to carry a neutral load but to bond the neutral to ground.
 
  #8  
Old 05-16-13, 08:27 PM
Member
Thread Starter
Join Date: Mar 2012
Posts: 11
Received 0 Votes on 0 Posts
One more thought

Since 2 of the 17 circuits will 240v I should only need 15 neutral terminals. So I only need to add 3.

Technically if there is no buss bar connecting the left and right bars then that install is incorrect.

As it is right now....if there is no buss bar connecting the left and right bars together then you are getting your neutral thru the neutral bonding screws which was not intended to carry a neutral load but to bond the neutral to ground.
It was my understanding that only in the Main service panel should the Ground(left bar), and Neutral(right bar) be bound together.

If you take a look at those pictures you'll see that the main feed neutral terminates into the right side bar which is isolated.

The main equipment ground feed terminates into the left side bar which is bound to the chassis.

in this panel the left side bar acts as the equipment ground not a neutral ground.
 
  #9  
Old 05-16-13, 09:18 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
It was my understanding that only in the Main service panel should the Ground(left bar), and Neutral(right bar) be bound together.
It is my understanding a neutral bar can not be repurposed as a ground. Both those bars are neutral bars so you need to add a ground bar. Notice both bars are on insulators. As a rule ground bars are not included with main breaker panels and what I see proves the rule.

Pizza Wrote:I have an existing 100 amp main breaker panel thats being used as a sub panel. The existing installer broke a bonding tab between the two neutral/ grounding bars on each side of the panel and used one side for the neutrals and one side for the grounding conductors.
However when they did this the choose to land the neutrals on the side that had about half the terminals as the grounding side. And I need to land four more neutral wires for new circuits.
My plan is to remove the grounding conductors off the terminal bar and install a separate grounding bar and bond it to the panel. Next I want to bond the neutral bar to the other terminal bar where the grounding conductors were once landed so I can get more spaces to land my neutrals. My thought was just to run a number 4 between the terminal bars and bond the that way. Anyone see a problem with this?

mike7330 Replied:
No. You would violate the listing of the panel. You need to find the “bonding tab” or a new one to return the panel to the original design. I have run across this with the General Electric panels, where the “electrician” removed the insulated neutral crossover bar and installed grounds on one side and the grounded conductors on the other, The property owner was lucky, the bar was left in the bottom of the panel and I was able to correct. Good luck
Source: Bonding Neutral Bars
 

Last edited by ray2047; 05-16-13 at 09:50 PM.
  #10  
Old 05-17-13, 06:38 AM
Member
Thread Starter
Join Date: Mar 2012
Posts: 11
Received 0 Votes on 0 Posts
I was able to do a little more research based on the suggestions I got here. I found that this panel is a multi-use panel. Unless its going to be used as a main service panel, or a sub-panel with more than 12 circuits then you don't have to buy the extra ground bar. The attachments/parts included with the panel allow for the left neutral bar to be used instead. I'm guessing the original installers didn't plan to use more than 12 slots. Now that I have added the new circuits I need to also add the ground bar. Thank you guys VERY much for helping me figure that out!
 
  #11  
Old 05-17-13, 07:43 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
Thanks for letting us know what you found. Be sure to add the jumper between the two neutral bars.
 
  #12  
Old 05-17-13, 12:52 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
Received 1 Vote on 1 Post
I was able to do a little more research based on the suggestions I got here. I found that this panel is a multi-use panel. Unless its going to be used as a main service panel, or a sub-panel with more than 12 circuits then you don't have to buy the extra ground bar.
Good research.

Now that I have added the new circuits I need to also add the ground bar.
Yes. Any old generic bolt-in ground bar will work, provided it has enough openings left after you nount it. One from GE might have mounting holes that will line up with holes in the box, but I don't see those in your pictures. Doesn't matter - just drill and tap what you need.

Be sure to add the jumper between the two neutral bars.
Tight. Each of the two add-in lugs for the 3 AWG wire will mount into two adjacent slots on each bar. That will leave 10 slots on each bar for branch neutrals - 20 total. That should be enough.

Don't forget to remove the screw that's bonding the left bar now.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: