Neutral bus bar in service pannel


  #1  
Old 11-10-03, 12:51 PM
dvos56
Visiting Guest
Posts: n/a
Neutral bus bar in service pannel

I have an older service panel with only a neutral bus bar (no grounding bus bar). To update the house, I would like to ground some of the circuits and add a few more branch circuits. I know that it is ok to use the single bus bar for both neutral and ground but currently the single bus bar is just about full of conductors and I need to add several more to finish this project. Is it acceptable to add another bus bar and connect it to the existing bar? If so, what is the recommended bonding jumper for the connection?

As a side note, there are a few small holes on the service panel that could be used to mount the bus bar, but they are not threaded. I don't see a good way to connect a new bar, are there any best practices on how to go about this?

thanks,

Dan
 
  #2  
Old 11-10-03, 04:17 PM
J
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 8,079
Received 530 Upvotes on 434 Posts
Post a make and model of your service panel. Someone will know if the bar is available for your panel.
 
  #3  
Old 11-10-03, 07:48 PM
dvos56
Visiting Guest
Posts: n/a
joed,

Thanks for the reply. My service panel is a Arrow Hart/Murray. It is a little unclear as to what number is the model number. Here are some of the numbers I noticed.

On the panel door by the manufacturer it says E9569
Under the schematic it has the number 58003-02-01
Near the service cable entrance the number 66560-7 is stamped into the rear side of the service box.

The panel door literature also states that the following ground bar kits can be used for this panel:

19 Hole LX073M
23 Hole LX074M

It sounds like I need one of these. Assuming that is true, what is the best way to locate one of them?

Thanks again!
 
  #4  
Old 11-11-03, 11:41 AM
J
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 8,079
Received 530 Upvotes on 434 Posts
Go to your local electrical supply house or order one online.

Here is one I found online with a google search of "murray ground bar kit".
 
  #5  
Old 11-11-03, 12:04 PM
dvos56
Visiting Guest
Posts: n/a
Thanks Joed - that is an exact match!

I am assuming that this new ground bar should be bonded to the existing neutral bus. Are there regulations on the wire size for this jumper? Should I use the size of the conductor going to the ground element as an adequate guide? In this case it is a stranded #4 AWG.
 
  #6  
Old 11-11-03, 02:48 PM
J
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 8,079
Received 530 Upvotes on 434 Posts
I believe bonding it to the metal case would be sufficient. The neutral and the ground are bonded in the main panel.
 
  #7  
Old 11-12-03, 03:20 AM
sagamisan
Visiting Guest
Posts: n/a
wait a second guys

hey devos before you add that buss is it possible for you to gain enough N. buss terms. if you were to double up on each hole, that is, put TWO#12cu awg or TWO#14cu awg in one hole?
I believe AHM panels have turned into MURRY panels (Home Depot carries them) and a Murry panel N. buss is rated for that.
Check rating on inside cover (if it's still there) it will say.

If you must add a larger buss .DONT just screw it to the can (thats NOT good) that leaves the potential of all your return load going through one or two little screws. Replace existing buss with a larger one in the exact way the other was mounted. and it must be UL listed for that panel . remember DONT just use screws imagine having to replace all of your electrical toys in your home OUCH!!! ive seen it happen

good luck
i hope this helps

sagamisan
 
  #8  
Old 11-12-03, 04:35 AM
J
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 8,079
Received 530 Upvotes on 434 Posts
You can't by code double up on the neutral wires. You can double up only on the ground wires.
 
  #9  
Old 11-12-03, 09:13 AM
brickeyee
Visiting Guest
Posts: n/a
Notice that the new bar is a 'ground bar'. you cannot land nuetrals on the bar. Move all the grounds to the new bar and you should have enough nuetral holes. If you are using the 1/2 size or double breakers be sure the anel is listed for them. Many older panels are not.
 
  #10  
Old 11-12-03, 09:43 AM
dvos56
Visiting Guest
Posts: n/a
Thanks for the tip. It was my plan to move the existing ground wires to the new bar (there are only a couple of them right now). I also managed to find a local place that sells the exact ground bar for my panel. I was ready to do the installation until I read your note about some panels not being listed to handle half size breakers. This is the first I have heard or read anything like that. The half size breaker is the same size as the standard single pole breaker and its combined capacity is not more than 30-40 Amps. What is the potential problem and how can I determine if the panel is adequate?

Thanks again,
Dan
 
  #11  
Old 11-12-03, 10:11 AM
dvos56
Visiting Guest
Posts: n/a
sagamisan:

Thanks for the advice. I considered doubling the number of conductors per terminal but that probably would not give me enough room. The last thing I want is to be 75% done with the project and be stuck deciding if I should try to get away with pigtailing a bunch of grounds to the bar.

The available bars for the Murray panel are not very large (~6 inches) so I don't think a total bar replacement is an option here. I plan to add a second bar (the panel was made for doing that) and bond the two bars with a #4 AWG jumper.
 
 

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