Panel Ground Bar - Too Many Circuits

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  #1  
Old 07-12-06, 05:38 PM
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Panel Ground Bar - Too Many Circuits

To start off, let me defend some of us DIYers. My home was flooded during Katrina. Some people sat around crying that no one was helping them, but many many more took the approach that I did - we saw opportunity and dug in.

I personally saw opportunity to make a 60 year old house new again. I decided there was no better time to rewire a house completely than while it was gutted floor to ceiling. I asked some questions which I thought were simple and received a handful of responses both giving advice and telling me that I was a moron and had no place around electricity. The moron comments made me more determined than ever to do it myself, but the honest efforts to help me helped tremendously. They made me realize that I was certainly in over my head.

Did I give in and hire a professional? Not a chance with the post-Katrina pricing in New Orleans, and this being an item not covered by insurance. I bought a couple of books that were recommended, and spent 3 weeks of eveings and weekends studying, asking questions, and planning. The result was me hiring a professional for 2 hours to review my plans and give advice. I then hired 2 electricians (I'll explain why 2 in a minute) to give my work a once over and certify that I didn't make any potentially hazardous mistakes.

In the end, I was offered a job by both. (And accepted neither since this was one of the most back-breaking jobs I've ever done! God bless you all, now that I've done it all once I'll hire an electrician to replace a switch in the future.)

Now for the question:

I have finished all of the rough-in and am wrapping-up the panel, but I have a grounding bar with 27 spaces and 30 circuits. when I asked the electrician what to do with the last 3 ground wires while he was double-checking my work, he told me to "sneak them in and hope the inspector doesn't notice." This made me second guess him and I hired the second electrician to verify my work - same question, same answer. I'm proud of my work, and I hate to "cheat" on this last little item, but I get the sense that this is standard practice and has no negative effect on the system.

Are there other options, such as adding a second grounding bar?

Thank you all!
BP
 
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  #2  
Old 07-12-06, 05:53 PM
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Originally Posted by d088
To start off, let me defend some of us DIYers. My home was flooded during Katrina. Some people sat around crying that no one was helping them, but many many more took the approach that I did - we saw opportunity and dug in.

I personally saw opportunity to make a 60 year old house new again. I decided there was no better time to rewire a house completely than while it was gutted floor to ceiling. I asked some questions which I thought were simple and received a handful of responses both giving advice and telling me that I was a moron and had no place around electricity. The moron comments made me more determined than ever to do it myself, but the honest efforts to help me helped tremendously. They made me realize that I was certainly in over my head.

Did I give in and hire a professional? Not a chance with the post-Katrina pricing in New Orleans, and this being an item not covered by insurance. I bought a couple of books that were recommended, and spent 3 weeks of eveings and weekends studying, asking questions, and planning. The result was me hiring a professional for 2 hours to review my plans and give advice. I then hired 2 electricians (I'll explain why 2 in a minute) to give my work a once over and certify that I didn't make any potentially hazardous mistakes.

In the end, I was offered a job by both. (And accepted neither since this was one of the most back-breaking jobs I've ever done! God bless you all, now that I've done it all once I'll hire an electrician to replace a switch in the future.)

Now for the question:

I have finished all of the rough-in and am wrapping-up the panel, but I have a grounding bar with 27 spaces and 30 circuits. when I asked the electrician what to do with the last 3 ground wires while he was double-checking my work, he told me to "sneak them in and hope the inspector doesn't notice." This made me second guess him and I hired the second electrician to verify my work - same question, same answer. I'm proud of my work, and I hate to "cheat" on this last little item, but I get the sense that this is standard practice and has no negative effect on the system.

Are there other options, such as adding a second grounding bar?

Thank you all!
BP
Sorry to hear of your loss. Very glad it will work out.

1) Thanks from all of us for the compliment !!!!
(the good ones make it look easy)


2) Yes this is standard practice, and I have never been called on it. Your integrity is admirable, and glad you asked.
Hopefully, if this Country has more soles like you, we should be alright. Best wishes and let us know how it all turns out.
 
  #3  
Old 07-12-06, 06:04 PM
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If you look closely at the label on the inner side of the door to your panel you quite likely will find out that some (or all) of the screw terminals on the neutral and grounding busses allow for multiple wires. Usually only two wires and usually only #12 and #14 copper.
 
  #4  
Old 07-12-06, 06:12 PM
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I guess that I should try to help others out too. The best book that I used was Wiring A House by Rex Cauldwell. Part of Taunton's For Pros by Pros series. It is definitely one of those books that I'll keep handy for a long time.

BP
 
  #5  
Old 07-12-06, 06:57 PM
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Just be carefull... No good deed goes unpunished.
 
  #6  
Old 07-12-06, 07:42 PM
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Originally Posted by lectriclee
No good deed goes unpunished.
That is the truth! I saved my employer hundreds of thousands of dollars (no, I wasn't running conduit and three-phase circuits ) and my "reward" was the elimination of the job.

I had the last laugh, though. I spent another two years (same large company) in a different location doing ABSOLUTELY NOTHING and then retired.
 
  #7  
Old 07-12-06, 09:56 PM
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The NEC only allows one neutral to be terminated per space on a buss bar. Depending on the make of panel, up to 3 ground wires may be terminated per space, sometimes of mixed sizes. Read the panel label.
 
  #8  
Old 07-13-06, 04:32 AM
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If you truly are out of space, even after doubling ground wires (if allowed), then your only choice is to add another buss.
 
  #9  
Old 10-20-06, 09:13 AM
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I'm at the house waiting on the inspector, so I'll let you all know how it goes and post some pictures of the final product after.
 
  #10  
Old 10-20-06, 10:45 AM
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I passed! I passed! I passed! Next step - sheetrock!

A couple of pictures of the panel can be found at:
http://www.perezweb.net/images/Panel-001.jpg
http://www.perezweb.net/images/Panel-002.jpg

Ben
 
  #11  
Old 10-20-06, 11:43 AM
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Congrats!! Always feels good, doesn't it? I passed my mechanical and plumbing rough-in inspections for my addition yesterday and and VERY relieved!

I'm surprised he passed the bundled NM through the top of the panel, though- code requires strain relief for NM exiting the panel. Code also requires derating if you bundle more than 2 NM cables for longer than 24", as heat build-up could post a fire hazard. With as many as you have there, you'd be limited to 10A on each #12 cable. Nice tidy professional-looking job, too, your care really shows.
 
  #12  
Old 10-21-06, 08:16 PM
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Help me out here. Is there a valid concern with the bundled wires posing a fire hazard? I'd hate to redo the panel, but I'd hate even more to know that my work caused a fire.
The electrician recommended bringing the wires in this way and the inspector didn't say anything about it...
Thanks,
Ben
 
  #13  
Old 10-21-06, 08:55 PM
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Honestly, there isn't significant risk, given the VERY low likelyhood of maxing out all those runs simultanously, which is really the only way the temperatures will exceed the 60C rating of the cables. What you did is rigorously rejected in some areas, but common practice in others. Either way, the inspector OKed it, so I wouldn't worry about it
 
  #14  
Old 10-21-06, 09:25 PM
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OK good. I wouldn't expect to ever reach 1/2 capacity of any but a few of the circuits. I intentionally overwired the house, because if I ever have to go back to this panel once I'm done it will be too soon.

This is only a 3 bedroom, 2 bath, 2000 sf house, and I ran 30-something circuits. Each room has a minimum of one circuit and anything that will have even the most insignificant electrical load has two with the kitchen having six.

Anything that I could do to lessen the risk even further without redoing the panel completely?

Thanks for the help and the heads-up on the PM.
Ben
 
  #15  
Old 10-22-06, 04:54 AM
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Grover Wrote: "I'm surprised he passed the bundled NM through the top of the panel, though- code requires strain relief for NM exiting the panel."

I live in an area not for from the OP and have seen many boxes and everyone was wired exactly that way, coming in bundled no strain relief. Not saying it isn't a violation of NEC or there is not a potential problem but that is the way it is almost always done in this area.
 
  #16  
Old 10-22-06, 07:01 AM
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It takes advantage of a loophole in the NEC that's allowed in some areas, and disallowed in others, depending on the inspectors.

- strain relief on NM is required at the panel. This usually requires individual cable clamps on each cable
- NM cables must be secured within 12" of every box. (NEC 334.3)
- The staples must be UL listed for multiple cables of that size.
- 310.15(B)(2) requires de-rating of cables when more than 3 current carrying conductors are run together.
- 310.15(B)(2)(a) allows you to NOT de-rate cables if it's run less than 24"
- 334.80 allows derating NM based on the 90 degree charts- ergo, #12 NM is already derated 66% and #14 is already derated to 60%.
- Derating is not required if conductors maintain spacing equivilent to their overall cable widths.
- There are a few other codes related to conduit, conduit fill and plugging holes in panels that are pretty much mutually exclusive here, with respect to installing the conduit.

What some inspectors allow (and what you did) was to put a short piece of PVC conduit on the top of the box, and then immediately fan out and staple cables individually once out of the conduit. This allows you to ignore the strain relief rule, but the length is short enough to not get nailed with the derating rule. The letter of the law says it's legal, but it does violate the intent of the law.


I don't mean to scare anyone (this method is VERY common and apparently perfectly safe, too, given the loads in residential construction), but there are studies like this that contend that even following the strict letter and intent of the law isn't safe enough:
http://www.copper.org/applications/electrical/building/pdf/bundle_evaluation_report.pdf
 

Last edited by grover; 10-22-06 at 07:17 AM.
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