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Discussion Starter · #1 ·
I was just about to install a sub panel in my 3 unit apt bldg. I wanted to check another panel on a different floor and noticed the neutral bus bar was bonded to the panel box.

I can understand the reason why this was done but thought it was a definite NO NO in sub panels???

My main panel the neutrals and ground are connected, the ENTIRE building is 2 wire bx cable, no legit copper ground anywhere just the metal armor.

So now what? Do i install my other sub panel (which contains a ground bus but I have no wires to put in it) and bond my neutral bus to the box again? I get it needs a path to the main but other than doing it wrong really what option is there when I have 14-2 and 12-2 bx cable everywhere? Or just remove the neutral bus bonds and rely on the bx alone originating from the main to keep a ground connection - basically any advice on the best of 2 evils Thanks!
 

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I have a few questions just out of curiosity: Are you replacing an existing sub-panel with a new one, or actually adding a new sub-panel? What's the wiring for the feeder from the main to the sub? When you say "BX" do you mean "AC"?

I'm probably no help to you, as my advice would be to hire an electrician.
 

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I was just about to install a sub panel in my 3 unit apt bldg. I wanted to check another panel on a different floor and noticed the neutral bus bar was bonded to the panel box.

I can understand the reason why this was done but thought it was a definite NO NO in sub panels???

My main panel the neutrals and ground are connected, the ENTIRE building is 2 wire bx cable, no legit copper ground anywhere just the metal armor.

So now what? Do i install my other sub panel (which contains a ground bus but I have no wires to put in it) and bond my neutral bus to the box again? I get it needs a path to the main but other than doing it wrong really what option is there when I have 14-2 and 12-2 bx cable everywhere? Or just remove the neutral bus bonds and rely on the bx alone originating from the main to keep a ground connection - basically any advice on the best of 2 evils Thanks!
There is no "best of 2 evils," only the proper way to do it, and that's to call a licensed electrician.
 

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Discussion Starter · #4 ·
In the buildings paper work there is a receipt from a "licensed electrician" that says - install 30amp sub panel in 2nd floor. That's all, there's no detail on parts, material or labor or total dollar amount. Just abc electrical contractors and a scribbled signature - completed 15 years ago.

The problem has mostly been corrected this far. New 10-3 lines have been ran to all floors and new sub panels are going in today after some minor framing changes to make them fit correctly. Still going to use the ac as a ground path since 3rd floor is rented using the 2nd floor as the complete gut to get all the cables run. Already pulled all 70 receptacles plus switches and light fixtures to check every box with meter. Plus going to eliminate a majority of branch circuits and re run them that have caused severe box over crowding, 2-6 wires beyond the box max capacity in some cases - worst being at the light fixtures. You can literally see screwdriver marks on wires where they tried to stuff them as deep as they could to add another line.
 

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What do you think is the reason on the bonded neutral bar?
Kastoria mentioned to me via PM that the original feeders were 2-wire, black and white, with the white re-purposed as hot and connected to the 2-pole breaker in the main panel. With the neutral bonded to the panel at the sub-panel, the AC was originally being used as the (current-carrying) neutral.
 

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You say 2-wire? Is that just 2 wires? #2 wire? Or 2ga wire? Kind of confused here. I looked at this post some time ago and kind of shook my head but now "curiosity killed the cat" you have my attention. Any sub-panel must have 4 wires, 2 for line, 1 for neutral and one for ground. Size of wire will be determined by the load which is determined by a load calc which will also determine whether or not the main panel can handle the extra load applied to it. Is the A/C circuit now being discontinued so the neutral may be used? Is the neutral even large enough "doubt it" to be used? Where are you getting your ground from so the sub panel may be bonded? Is there anything in your local code that does not allow you to run a new service from the main panel up the outside of the structure to feed a sub panel if a new line cannot be run within the structure?
 

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If you bond neutral and ground wire in any subpanel then you must kept them separate. The neutral bus must be isolated from the panel chaser, there one of subpanels seems to one of either in ground or neutral bus bar, installed a better subpanels that would suitable for both. Here an electrician should keep everything with him , take care that ground wires not let to install the ground bars.
 

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So, what happened? What you do?

Answer: The neutral needs to be bonded at the main panel only(or first switching means) to bond the two ground potentials together. From there, there needs to be a separate ground and grounded(Neutral) going to any branch circuits originating from main panel.
 

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Thom
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How the rules are enforced are location specific. Here, any circuit modified must be made code-compliant back to it's panel and, if it is a sub panel, that sub must be made compliant back to the main. The point is, any circuit touched must meet current code back to the main panel and, that panel must also meet code.

It seems harsh but, that is our rules. Oftentimes that means on a remodel, bringing the main panel up to code then all circuits added are to code and none of the existing circuits are modified.
 

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How the rules are enforced are location specific. Here, any circuit modified must be made code-compliant back to it's panel and, if it is a sub panel, that sub must be made compliant back to the main. The point is, any circuit touched must meet current code back to the main panel and, that panel must also meet code.

It seems harsh but, that is our rules. Oftentimes that means on a remodel, bringing the main panel up to code then all circuits added are to code and none of the existing circuits are modified.
Wow, that is above and beyond what I'm used to and we're in what I thought was a stringent area.

Are they making you adhere to the AFCI rules too Thom?
 

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How the rules are enforced are location specific. Here, any circuit modified must be made code-compliant back to it's panel and, if it is a sub panel, that sub must be made compliant back to the main. The point is, any circuit touched must meet current code back to the main panel and, that panel must also meet code.

It seems harsh but, that is our rules. Oftentimes that means on a remodel, bringing the main panel up to code then all circuits added are to code and none of the existing circuits are modified.
Usually around here you won't have to change the panel if it was originally code compliant, if you don't touch anything in it (including breakers). It's an incentive to use AFCI receptacles, when AFCI rules are enforced.
 

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How the rules are enforced are location specific. Here, any circuit modified must be made code-compliant back to it's panel and, if it is a sub panel, that sub must be made compliant back to the main. The point is, any circuit touched must meet current code back to the main panel and, that panel must also meet code.

It seems harsh but, that is our rules. Oftentimes that means on a remodel, bringing the main panel up to code then all circuits added are to code and none of the existing circuits are modified.
That' how it is done here as well.

That's when the interior designers with all their pretty pictures of new appliances crap their panties. They never think of the electrical end.
 

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Thom
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Wow, that is above and beyond what I'm used to and we're in what I thought was a stringent area.

Are they making you adhere to the AFCI rules too Thom?
AFCI's almost everywhere. Not in hallways, not in areas that have GFCI's, everywhere else (all living spaces)

Years ago I did a small job, 1 additional circuit, 1 receptacle, promised by the LL. That required a service change. Expensive receptacle.
 
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