New 200A Service

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mattyp

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If a new residential 200A combination meter/panelboard is installed away from location of old service and the old 100A panelboard is turned into splice box (breakers and meter removed) in lieu of subpanel, can one common ground & one common neutral from new panel be used to feed old panel circuits. Not sure the NEC covers this type of install.
 
That's a good question. Although I can't find an NEC reference, I can't imagine it is ok. My instincts and experience tell me that none of the branch circuit conductors can be intermingled (except the equipment ground). I'll be watching for the opinions of the heavy hitters in this forum on this issue.

Bob
 
My first response would be to say no....

As a inspector, I have to view remodel installations carefully, and a shared neutral from multiple circuits on different phases would be problematic at best, and that should be confined to the distribution panel. What you want to do is use the neutral buss in the old panel and splice in new feeder hots from the new panel.......pretty sloppy would be my first impression.

Splices, if done neatly and in NEMA approved boxes that are accessable for the application is what I look for.

I would have you remove the old meter and panel box. bring your new feeders into the home and junction them, assuming the wire you were tying onto was of the same size and had grounding conductors. Or, install a Nema approves splice box....NEMA 3R, of the appropriate size, and splice each feeder, The old box, once the harware is removed, can not be depended on to be weather tight.

What you have done or are doing is going beyond the simple meter replacment or panel replacement which would not generally entail the replacement of the entire branch circuit.

Once you replace a feeder, then you get into a number of code compliances that you must meet, and grounded outlets, GFCI's, AFCI's and the like all come to mind.

I try to be reasonable on remodels, and I can't say that I might approve a number of different ways to tackle this problem, so I'm giving you the range of things that might be necessary. There are a lot of variables that need to be looked at.
 
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mattyp said:
If a new residential 200A combination meter/panelboard is installed away from location of old service and the old 100A panelboard is turned into splice box (breakers and meter removed) in lieu of subpanel, can one common ground & one common neutral from new panel be used to feed old panel circuits.
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I know this wasn't part of your question, but why not turn the old box into a subpanel, and just feed it from the new service?
 
bkludecke said:
That's a good question. Although I can't find an NEC reference, I can't imagine it is ok. My instincts and experience tell me that none of the branch circuit conductors can be intermingled (except the equipment ground). I'll be watching for the opinions of the heavy hitters in this forum on this issue.

Bob
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You are correct....

In my experiance, residential homes can suffer some serious problems when neutrals open for any reason. It often causes some 200 volts to be applied to lighting and general use outlets, depending on what opens, causing everything from electrical shock, fire and being scared out of their minds.....:)

Neutrals must be carefully done and distributed, and this should be confined to a accessable distribution panel and at one place.
 
Using it as a subpanel would work if it can meet today's rules for panel locations, can be made non service rated, and has breakers that don't cost an arm and a leg or are fire prone.

The rule that would complicate using one large neutral and grounding conductor would be the rules that say all conductors of a branch circuit must be run together (not sure of article number). If you run a large conduit to this panel with one EGC, one large neutral, and a bunch of ungrounded conductors, that would be legal. But you may have a derating issue in that conduit.

If you use multiple conduits, you'll need a neutral and EGC in each.

Having a common neutral wrecks having the ability to have any AFCI protected circuits from that splice box. But you could run a separate hot/neutral/ground for any AFCI circuit that needs to go through that splice box.

I think you'd be better off running normal circuits to that box and just splicing neatly inside it. You will want to keep the grounding bus bar, since you'll have so many and they all must be interconnected.
 
I would say that a single EGC is okay, as long as it's adequate foe the largest circuit.

As for the neutrals, I'd pair up the circuits size-wise, and run 3-wire circuits for each pair.
 
Curious

If you are going to supply the existing 100A enclosure with a single neutral I guess your running raceway, yes no??

If your running pipe why not run the neutrals,


Charlie
 
dlhoule said:
When upgrading to a larger panel don't you have to put in required AFCIs?
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The OP didn't indicate his location, so I'll assume he's in NJ and say NO :)
 
Wouldn`t handle ties come into play if the mentioned branch circuit(s)Terminated on a single yoke.Shared neutrals on circuit feeds have been a common practice for years.I have always thought that a single phase service can share a neutral between phase A and B,also three phase can share A,B,C on a single neutral.The problem with shared neutrals come into play when they are shared on the load side of a circuit.A loose connection on a neutral can cause devistating consequenses,with electronics etc.
 
suemarkp said:
Using it as a subpanel would work if it can meet today's rules for panel locations, can be made non service rated, and has breakers that don't cost an arm and a leg or are fire prone...

...I think you'd be better off running normal circuits to that box and just splicing neatly inside it. You will want to keep the grounding bus bar, since you'll have so many and they all must be interconnected.
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BTW, install is in CA, one 1-1/4" NM raceway. The old panel (C-H 1960) would have to be modified to meet subpanel requirements (ground and neutral bus bar are one in the same). I think running one common EGC and individual circuits for the remaining is the best call. Thanks for all the great feedback on this topic.
 
wirestripper said:
Once you replace a feeder, then you get into a number of code compliances that you must meet, and grounded outlets, GFCI's, AFCI's and the like all come to mind.
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That would be a local, rather than an NEC, issue. I replace feeders all the time, and I don't have to ground all the outlets, put in GFCIs, AFCIs, etc., unless I'm working in a jurisdiction that has local ordinances to that effect.
 
jeff43222 said:
That would be a local, rather than an NEC, issue. I replace feeders all the time, and I don't have to ground all the outlets, put in GFCIs, AFCIs, etc., unless I'm working in a jurisdiction that has local ordinances to that effect.
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Yes, I would agree with that. All jurisdictions are different, and what we try to do is encourage remodels to include upgrades in the kitchen and bathroom areas.

At present, we do not require it or mandate it.

Sometimes it is simply common sense to do so. The feeders replaced are usually due to overload in these areas, or extensive remodeling. I can suggest things to be done, but what actually gets done is the decision of the home owner.

The electrician has a fiduciary duty to point out safety improvements that he can make if he notes a need for them. He is protecting himself and his company as well as the owner. If he confines his work to a simple panel changeout, that is fine, but if he gets into the house with feeder replacements and sees problems developing, he should do what he can to convince the owner to correct them at that time, or as soon as possible.

I hope that explains why I made that comment....:) But you are right, the code would not require the upgrades. The local jurisdiction has that responsibility.

Edited for spelling.....Unnnnngh!
 
allenwayne said:
Wouldn`t handle ties come into play if the mentioned branch circuit(s)Terminated on a single yoke.
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Yes, which is what I was referring to when I said . . .
. . . handle-ties would not be required (unless, of course, they are for the usual reasons.)
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Excepting GFCIs, AFCIs, and local amendments to the NEC, the NEC would permit just such an installation as asked by the OP.

If the neutral conductor is sized properly, this would be a permitted installation, because it is so different than most would install, it seems like a violation. But as one poster mentioned, he could not find any prohibitions in the NEC, as there are none. Of course there are parameters that may make this type of installation infeasible, but in some instances it is fine.

We will hear the typical " I would not do this", etc..., the NEC is a minimum document and installing to a better standard is fine.... just not always cost effective when bidding work.
 
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