How would you do this?

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busman

busman

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Northern Virginia
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Master Electrician / Electrical Engineer
Needing to add a subpanel adjacent to a main panel due to over-crowding and need to add new circuits. In order to make space for the 2-pole (this is residential) CB in the main panel, two circuits need to move to the subpanel. I see two options, wondering which you would do and why.

1) Pull a couple Romex out the top of the main and move them over to the adjacent subpanel (if they are long enough). Seems like more work, but maybe neater.

2) Wirenut some extensions to the hots and neutrals in the main and run thru the same nipple that connects the main to the sub for the subpanel feeders. Probably not as neat looking (but not normally in view). Also, some slight chance in more crowded panels of not grabbing the correct neutral that correlates to the hot and causing induction heating.

I'm leaning toward the latter being faster.

Thoughts if you will please.

Thanks,

Mark
 
If you choose option #2 the nipple should be 24" or less otherwise derating may require you to increase the conductor size. Running a few circuits through the existing panel to the new panel would require labeling to indicate that there are through circuits in the panel.
 
infinity said:
Running a few circuits through the existing panel to the new panel would require labeling to indicate that there are through circuits in the panel.
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Learn something every day, I never would have guessed that simply using a panel as a pass through, and not physically connecting to the panel, except for bonding, would require me to label.
 
I had forgotten about the labeling requirement which is fairly new, I believe. Do you know the Code section by chance, or should I search for it?

Thanks much. Glad I asked the question.

Mark
 
200.4(B) or is there another one also? With that said, I've never had an inspector enforce this on Panel change-outs yet, but they probably should. Many of the panel change outs I do have a large JB to avoid a pile of wirenut spaghetti in the new panel. And yes, this was new for 2014.

Mark
 
hillbilly1 said:
NEC 312.8 (A)
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A warning label complying with 110.21(B) is applied to the
enclosure that identifies the closest disconnecting means
for any feed-through conductors.

This seems rather ridiculous when the subpanel is 2 inches away, but I'll play along. I think the neutral labeling requirement makes much more sense and codifies what I was saying about possibly confusing neutrals in my first post.

Another thought, would that 312 requirement apply to those Reliant generator transfer switches?

Mark
 
busman said:
would that 312 requirement apply to those Reliant generator transfer switches?
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Assume you are referring to the individual branch circuit type. The primary Overcurrent remains in the panel of origination, but I would think the additional marking indicating a secondary power source for each branch effected by this additional power source would apply. 705.10, 702.7,110.21
 
Not so fast..... the main disconnect of the main panel is the closest disconnect because the main panel is feeding the sub panel. So if you turn off the main panel disconnect, the feed through conductors are also de-energized.

So the "closest" disconnecting means, is the main in the same panel.
 
Obviously the warning is to let someone know that there are still energized conductors in the panel after you turn off the main. I don't think a warning label is necessary
 
When the panels are connected by a nipple, I see Option 2 far more often but in many cases the Romex isn't long enough or easily accessible to lean to option 1
 
augie47 said:
When the panels are connected by a nipple, I see Option 2 far more often but in many cases the Romex isn't long enough or easily accessible to lean to option 1
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Agreed, they are usually not long enough or you can't get to the staples, so Option 2. Glad I started this thread, if nothing else than to remind us all of the marking requirements. It's been a good refresher for me.

Thanks to all.

Mark
 
Sea Nile said:
And how will you mark it? "Warning.. there are feed trough conductors in this panel, the closest disconnect is in this panel"?
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I wasn't saying I would mark it in the transfer switch case. I was just saying that the thread was a good reminder to us all of the conditions that would require marking.

Mark
 
Sea Nile said:
And how will you mark it? "Warning.. there are feed trough conductors in this panel, the closest disconnect is in this panel"?
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Not always are sub or secondary panels that might be side by side fed from the adjacent panel. With Primary disconnects located outside usually near meter It can be fed from that.
Requirement not just related to main service breaker, Branch circuit feeder breakers also. How many times is work performed Live from necessity such as testing. Also for identifying associated Neutrals for pass thru feeders, spliced connectors and potential to disconnect that the branch circuit originates outside of panel you are in.
Not to mention convenience, tracing a wire back trying to disconnect power. It enters one panel but for some reason none of the breakers there turn off the circuit.
Also no requirement the secondary panel be adjacent or even in sight of first panel.

You want to make codes that can individually cover every possible alternative get ready for a legal library size code book.
 
Of course you are right, and I don't want a code book the size of Encyclopedia Britannica.

I was just reading what 312.8(A)(3) said specifically.

The main panel has the feed through conductors. So the label would go on the main panel.

The closest disconnecting means would either be the breaker in the main panel feeding the sub panel, or the the main breaker in the same panel.

So essentially, the warning label would simply state "to de-energize the feed through conductors in this panel, turn off the main breaker in this panel"

It's silly to have a warning like that, but you are correct.
 
augie47 said:
When the panels are connected by a nipple, I see Option 2 far more often but in many cases the Romex isn't long enough or easily accessible to lean to option 1
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You're able to leave the equipment ground alone that way is why I've done it. It's one less thing to mess with. But if going more than right next to it then I've removed them from the panel and done it clean and right.
 
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