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What makes a subpanel a subpanel?


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What makes a subpanel a true "subpanel?" What I mean is, like pic 1 here, all this little panels contain two fuses probably because of lack of service in the main. They aren't all subpanels right? So what do you look for in a panel to call it a "Sub?"

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Like this one... This panel is about 6 inches from the FPE main panel... Is this a subpanel? If yes, why?

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Originally posted by jodil

What makes a subpanel a true "subpanel?" What I mean is, like pic 1 here, all this little panels contain two fuses probably because of lack of service in the main. They aren't all subpanels right? So what do you look for in a panel to call it a "Sub?"

Like this one... This panel is about 6 inches from the FPE main panel... Is this a subpanel? If yes, why?

There's really no such thing as a "subpanel." It's a slang term. In the parlance of the NEC, there are just "panelboards." There aren't different kinds.

The NEC tells us to bond the neutral the grounding wires at or before the place where the service disconnect is. After that, the grounding wires and the neutral wires are supposed to remain separate. They're supposed to remain separate in panelboards, switches, appliances, fixtures, and anything else you can think of.

It's easier to think of "main panels" and "sub panels" for some things, but occasionally, it causes confusion and it's good to go back to the horse's mouth for the basics.

- Jim Katen, Oregon

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Given that 5 panel conglomeration in the first photo, you could make some strong arguments for taking it all out, updating the service to 200 amps, and consolidating it all into one panel.

I don't know how folks do stuff in your neighborhood, but in my area, that would be called a freakshow.

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Originally posted by kurt

Given that 5 panel conglomeration in the first photo, you could make some strong arguments for taking it all out, updating the service to 200 amps, and consolidating it all into one panel.

I don't know how folks do stuff in your neighborhood, but in my area, that would be called a freakshow.

Oh yeah, that too.

- Jim Katen, Oregon

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If you're not sure about the term "service disconnect", it's the first place all the power can be turned off. In some cases that can be a panel with only one large breaker in it, or an older-style knife disconnect switch, with no branch wiring at all. Doesn't matter; any panel after that point has to be wired as Jim described, whether 3 inches away or at the other end of the house.

If you get into panels located in separate buildings that can change (sometimes).

I'd estimate 2/3rds of the sub panels I look at are wired wrong, for one reason or another. I hope it's better elsewhere.

Brian G.

Just More Job Security [;)]

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  • 2 weeks later...

I call out incorrectly wired subpanels all the time. Some local electricians say neutrals can be bonded to the equipment grounds in subpanels if a metal conduit connects the two panels. I continue to call these out. What do you guys say about this specific example?

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Tear it out and upgrade the service.

Looks like they kept adding things over the years. Most of the items in the first photo are disconnects of one kind or another.

If the panel in the second photo is fed from the main panel it is a "subpanel". However: The ground and neutral should be seperated by removing the bar at the bottom. Eliminate this altogether by installing a proper service upgrade.

Is the FPE panel still operational or did they just feed through it?

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Thanks Eric. I've known some local electricians say that if the two metal enclosures are connected with metal conduit (like in my example of two adjacent panels a few inches apart) that it is really one enclosure and the 2nd really isn't considered a subpanel. I've still be calling these out, but was curious to know what you guys think in this instance. Sounds like I'm doing it correctly.

Thanks again.

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What makes a subpanel a true "subpanel?"

When it is installed on a submarine.

(sorry, all the good advice on that topic was already provided by others)

Originally posted by msteger

I've known some local electricians say that if the two metal enclosures are connected with metal conduit (like in my example of two adjacent panels a few inches apart) that it is really one enclosure and the 2nd really isn't considered a subpanel. I've still be calling these out, but was curious to know what you guys think in this instance. Sounds like I'm doing it correctly.

They are two enclosures, connected together. They are not "really one enclosure". There have been several threads on this subject, the most recent was within the past couple of weeks.

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Thanks Eric. I've known some local electricians say that if the two metal enclosures are connected with metal conduit (like in my example of two adjacent panels a few inches apart) that it is really one enclosure and the 2nd really isn't considered a subpanel. I've still be calling these out, but was curious to know what you guys think in this instance. Sounds like I'm doing it correctly.

Thanks again.

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Originally posted by msteger

Thanks Eric. I've known some local electricians say that if the two metal enclosures are connected with metal conduit (like in my example of two adjacent panels a few inches apart) that it is really one enclosure and the 2nd really isn't considered a subpanel. I've still be calling these out, but was curious to know what you guys think in this instance. Sounds like I'm doing it correctly.

Thanks again.

What we name the panel doesn't make any difference. We could call it "Bob," or "Steve," or "Sub Panel." It makes no difference.

There are just two simple rules:

Rule 1: The NEC requires that the neutral and grounding conductors be bonded to each other at or before the service disconnect.

Rule 2: After the service disconnect, the NEC prohibits those conductors from being bonded to each other.

There have been exceptions having to do with clothes dryer wiring and separate buildings, but they really don't apply to this particular thread.

It's got nothing to do with the name we give to a panel.

It's got nothing to do with how many encosures contain how many panels.

It's got nothing to do with the fact that thousands of electricians have played fast & loose with this rule for decades.

- Jim Katen, Oregon

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  • 2 weeks later...

I have been reading your thread and have a few questions. I have a main that has 3 breakers: 100A that feeds to a sub and runs most the house and (2) sperate 50A's for the A/C and Oven.

Currently the 100A sub has all the nuetrals and grounds tied to the same bar. This sounds incorrect per this thread. The sub is run via SE type 3 wire that has 2 hots and (2) seperate grounds (not in jackets). What are my options here:

Can I use one of the 2 frounds as the neutral or will I have to reqire for true 4 wire to have the neutral and grounds seperate at the sub?

Doesn't the NEC code say I can use the SE type wire in this manner? The house was built in 1982.

Thanks for all the responses.

C

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CW, I'm a little confused. How does the SE cable have two separate grounds that aren't jacketed? One is usually wrapped around the two primary conductors, just under the outer jacket...where is the other one?

Brian G.

Dazed & Confused [:-boggled

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Originally posted by Brian G

CW, I'm a little confused. How does the SE cable have two separate grounds that aren't jacketed? One is usually wrapped around the two primary conductors, just under the outer jacket...where is the other one?

Brian G.

Dazed & Confused [:-boggled

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Those aren't two separate wires, someone just twisted the wrapped ground into two or three bundles instead of one (makes it easier to terminate at the neutral bar). Long story short, you only have three conductors and no way to correctly wire a sub panel with that cable.

Brian G.

Bearer of Bad News [:-indiffe

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