Extending Ground bar in main panel

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  #1  
Old 11-13-12, 04:46 AM
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Extending Ground bar in main panel

Here is my situation. I have a close to 100 year old house that was updated with a Murray circuit panel and 100 amp service some time before I bought this house 30 years ago.
The service box has 20 breakers and it's full. The box has a single neutral/ground bar where some wires are doubled up already. There are only 23 or 24 connectors on it.
I'm installing a transfer switch and need a couple more for the neutral and ground wires. This is the main box that has the main service wires and shutoff in it.

My question. Can I add a short ground bar inside the box by using a heavy jumper to the existing neutral/ground bar? That way I could spread out the ground connections to it a little and at least get the new and some of the old bare ground wires off the old bar and not ganged up so much?

I do plan on having an electrician check all my work before going live with it but in the northeast it's not easy to just call one up and have him pop over! For the last 15 months most have been hopping.

One last note. The existing ground/neutral is attached to the panel with screws and seems to have plastic standoffs of some sort. The ground extensions I can find are solid metal and would be screwed directly to the panel and connected to the existing bar with a heavy copper wire.

Any help greatly appreciated.
 
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  #2  
Old 11-13-12, 05:03 AM
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You should be able to add an auxillary ground bar to your panel. It should screw directly to your case.

Only move the grounds over to this bar. The neutral must stay on the original bar. One neutral per hole.
 
  #3  
Old 11-13-12, 06:45 AM
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Thanks for the quick answer PCbos.
Gotcha on the 1 neutral to a screw too. Adding the extra space to move grounds will help me make this happen.
Cheers
 
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Old 11-13-12, 05:24 PM
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The ground extensions I can find are solid metal and would be screwed directly to the panel and connected to the existing bar with a heavy copper wire.
The existing neutral bar is on plastic feet to isolate it from the panel box under some circumstances, but in your situation, the nuetral bar should be bonded to the panel box. You don't need to connect the new ground bar that is screwed to the box to the neutral bar using heavy copper wire. The box should be already bonded to the neutral bar and the box itself is the bond between the new ground bar and that neutral bar.
 
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Old 11-13-12, 06:49 PM
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Thanks again. I just figured the jumper might provide a bit of insurance. Guess if room gets tight I can utilize the extra holes though if I didn't.

The panel is screwed into a piece of plywood. The small bolts that came with the ground bar are not self tapping sort and I've read that sheet metal screws are not acceptable. Any info on what type I might get to fasten it down into the box?

Thanks again. This is really helpful.
 
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Old 11-13-12, 06:54 PM
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You could use a nut and bolt. A fine threaded machine screw would work if you can get two threads in the panel material.
 
  #7  
Old 11-13-12, 08:09 PM
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Unsure if my box will show what was spoken on as to neutral ,
but how can i tell if my box is bonded/grounded correctly.It does have a silver #6 seen in pic(at top ) going to copper pipe ,and outside box shows ground.
Is the older neutral
IMAG0121.jpg
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3.jpgbar
 
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  #8  
Old 11-14-12, 06:13 PM
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how can i tell if my box is bonded/grounded correctly
You can visually check for a bonding screw bonding the neutral bar to the box or some panels actually have a strap, usually made of copper, that attach the neutral bar to the box. You can also use a meter to check for continuity between the neutral bar and panel box. I see what appears to be a larger solid aluminum conductor that might be the one going to a cold water line. I also see what appears to be 4 stranded aluminum grounding conductors from SER cables, but no where do I see a copper grounding conductor going to a ground rod outside under the meter socket. The outside ground wire to the ground rod must be copper and cannot be aluminum.
 
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Old 11-15-12, 12:48 PM
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Any info on what type I might get to fasten it down into the box?
You can use two nuts and bolts, plus lock washers, to mount it to the side of the box. Or you can drill and tap through the back and into the plywood to make holes that machine screws can be threaded into.

In either case, you should scrape the paint off the box behind the new ground bar to ensure that it will be bonded.
 
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Old 11-16-12, 01:28 PM
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Hi
Thanks for the info.I used my digital meter and checked for ground .neutral is ok -tested neutral bar to box.I see 2 bolts coming in to support box - is that supplying the ground/bonding as to why it reads 0? Name:  IMAG0138.jpg
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Also noticed wire on outside of box at meter going into ground - is in earlier pics- is not copper though,
 
  #11  
Old 11-20-12, 07:27 PM
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Check Home Depot.

I went thru the same exact thing last summer. HD had a small ground bar that has a small mounting bracket that lines up with tapped holes in the panel.

From that I learned that grounds can be doubled up two to a screw, but neutrals need to be by themselves.

And like pcboss said, the new addon bar is only for grounds..

[edit]
Here is my original thread. Unfortunately the pictures are lost.
http://www.doityourself.com/forum/el...-attached.html
 
  #12  
Old 11-21-12, 05:26 PM
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Also noticed wire on outside of box at meter going into ground - is in earlier pics- is not copper though,
If it isn't copper, is it aluminum? Aluminum cannot be terminated any closer then 18 inches from the corrosive earth.
 
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Old 11-22-12, 06:52 AM
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I think that might be a plastic sleeve over the conductor.
 
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