Sub Panel One Side Not Working Properly

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  #1  
Old 02-05-15, 07:00 PM
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Sub Panel One Side Not Working Properly

I just installed a sub panel. All works fine on the right side bus, but the only way I can get the left bus to work is to connect the neutral and ground wire onto the same left sided bus. of course that's not the way it's suppose to be. Circuits on the left side will not work if I connect the ground wire to the grounding bus.

I do not see a tie bar in my main panel. I thought that may be creating part of this problem.

Help would be appreciated.

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Last edited by PJmax; 02-05-15 at 08:10 PM. Reason: inserted pics
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  #2  
Old 02-05-15, 07:03 PM
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Until a moderator approves your photo I cannot offer anything.
 
  #3  
Old 02-05-15, 07:13 PM
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The copper bar at the bottom of the panel needs to be installed between the neutral bars.
 
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Old 02-05-15, 07:20 PM
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Thank you much. I assume on the main panel.
 
  #5  
Old 02-05-15, 07:31 PM
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On the panel shown in the picture. Right now there is no way for the neutral current to return with the jumper missing.
 
  #6  
Old 02-05-15, 07:40 PM
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Is the feeder to the subpanel a 120/240 volt 4 wire feeder or a 120 volt only 3 wire feeder? A picture would help.
 
  #7  
Old 02-05-15, 09:29 PM
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I agree with PC, those two neutral bars are isolated from each other and it needs that copper "jumper" to allow the return currents to the supply wiring.

I noticed that the supply wiring looks a bit small for the size of the lugs. Check on the inside of the panel cover to see if the size of the supply wiring falls between the minimum and maximum sizes listed for the main lugs.

Joe, he stated it worked if he jumped the (isolated) neutral to the equipment ground bar so I have to assume it is a four-conductor supply.
 
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Old 02-06-15, 08:16 AM
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Thanks for you support and taking the time for some help.

I am using a 10 gauge wire and taking a regular main panel (I had an extra new one, Siemans SL series) and making it into a subpanel. I did not find a min/max spec anywhere.

I thought the tie bar is suppose to be removed on the subpanel. Not debating your guys, your are the experts, just letting you know where part of my confusion is coming from. I certainly follow the logic or tying the neutrals together. However, it dawned on me that I had not mentioned that this is a regular 125 main lug panel that I am using for the subpanel. Does that make any difference?
 
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Old 02-06-15, 08:32 AM
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I did not find a min/max spec anywhere.
The spec can usually be found in fine print somewhere on the label inside the panel door and is almost always stamped right on the lug itself. It can also be found in the Siemens catalog.

I thought the tie bar is suppose to be removed on the subpanel
The tie bar is removeable so that one side can be used as a ground bar. In your case, you are using both sides as a neutral bus and you already have a seperate ground bar so the tie doesn't get removed nor does the neutral bus get bonded to the panel can.

it dawned on me that I had not mentioned that this is a regular 125 main lug panel that I am using for the subpanel. Does that make any difference?
As long as the subpanel is in the same building and not in a detached building, the MLO panel is fine, this is what they are made for.
 
  #10  
Old 02-06-15, 08:34 AM
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I had not mentioned that this is a regular 125 main lug panel that I am using for the subpanel. Does that make any difference?
Not so long as it is in the same building as the main panel. If it was in a different building a disconnect is required when there are more then six breakers. (Usually in that case a main breaker panel is used so the main breaker can act as the disconnect.)
I am using a 10 gauge wire
. That is okay if it is protected by a 30 amp breaker in the main panel. (Looks like a lot of breakers for a 30 amp feed.)
I thought the tie bar is suppose to be removed on the subpanel.
I think the need to isolate the neutral bars in a subpanel may have confused you. (Sometimes the second neutral bar is used as a bonded ground bar. In that case it is disconnected.).
Does [using a 125 amp main lug panel] make any difference
There is no such thing as a subpanel. It is just slang for a service panel that does not contain the first OCPD (Over current Protection Device).

Dang, Joe types faster.
 
  #11  
Old 02-06-15, 10:17 AM
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You guys are the greatest. I did exactly as you said and all works fine.

Don't think I ever responded to your comment, but this is in installed in the same building about 3 feet from my main panel.


Thanks for the comment about the #10 perhaps being undersized. There's a story that goes with that decision, but the short of it was my last "sub-panel" (good learning for me when you said there really is not a sub panel, they are all service panel) was much smaller and I am upgrading. The 125 gives me more expansion. I realize that this next comment depends on what I do with the new panel, but I was thinking of changing out the #10 to two #2 for both hots and neutral and #6 for ground.

The lesson on the tie bar was a good one also, and cleared up confusion by me. You guys are great educators.

Much appreciated.
 
  #12  
Old 02-06-15, 11:07 AM
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Not all panels are service panels. Service panels are the location of the first means of disconnect are after the meter. It is also where the neutral and ground bond takes place. Anything else is just a panel.
 
  #13  
Old 02-06-15, 01:31 PM
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On my Siemens 125 ampere MLO panel the acceptable wire sizes for the lugs are #4 to 2/0. Although it would be contrary to code (not following manufacturer's instructions) if you are careful in securing the too small conductor under the binding screw the hazard in my opinion would be slight. Of course in this instance my opinion is worth every cent you paid.
 
  #14  
Old 02-06-15, 03:24 PM
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If it seems the wire is undersize for the lugs you can also connect a short length of larger size wire to it and put that wire in the lug.

Just one thing I'm still unsure of. Did you say you have this connected to a 30 amp breaker in the main panel?
 
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