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Discussion Starter · #1 · (Edited)
Hi folks,

I have 15 MC cables coming from above to connect to this CH panel. The electrician who installed it in 2009 (to replace a Federal Pacific panel, allegedly) ran large Romex bundles through the concentric knockouts which are now much larger than I need.

He also, unfortunately, added a custom 1-3/4" diameter hole that clobbered multiple prized 1/2" knockouts on the right side, and now I'm short on 1/2" knockouts. There was no need to do that, given that only a handful of cables were run through the custom hole.

Only two Romex cables will remain, and the other two are slated for removal.

I would very much love to convert the large knockouts to multiple 1/2" (for example, 3" becoming 4 x 1/2") but I'm not aware of a product to do this. Replacing the panel would require a hotel stay and involvement from the utility since I have no upstream disconnecting means, and it seems unnecessary.

I want to make the best possible use of the top access before resorting to bottom cable entry via the adjacent stud bay. My questions are

1. Is there a legitimate way to convert 2-1/2" and 3" diameter knockouts to multiple smaller ones? I can find reducer washers to 1/2" from any standard size (thanks, Garvin) but nothing that converts to multiple. The space is certainly there.

2. If I use standard reducing washers, do I also need locknut-style connectors to maintain bonding to the panel? I've used snap-in MC connectors everywhere else on the project and generally prefer them.

3. Do I need to electrically bond the fitting to the panel around the washers even if MC armor is not considered a grounding conductor?

My current thinking is:

1. Get knockout reducing washers for the three large holes, even if I get just one 1/2" hole from each. Buy some locknut-style saddle connectors for the MC to ensure the washers are clamped tightly to the panel. Run the Romex through the same 1-3/4" diameter knockout via reducing washers and a standard clamp connector with capacity for two cables.

2. Use duplex MC connectors for the two obvious candidates. (A little hokey, but I have some on hand.)

3. Run any leftovers through the adjacent stud bay and enter from below if needed.

Is there a better way to accomplish this short of swapping the panel?

Thanks!

A.

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I only know of a double MC connector for 2 cables. Possibly put a junction box above the panel (with an exposed blank cover for permanent access) then connect it to the panel with conduit. You can strip the MC cable long enough to pass thru without splices.
 

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Discussion Starter · #6 ·
Thanks for the input, guys. I found that the Arlington double-snap duplex (3838AST) fits--just barely--next to a single-cable connector in an adjacent knockout. This means I can use enough of the duplex connectors to meet my needs for this project, leaving the large knockouts closed with simple blank-out covers. Those can always be repurposed with reducing washers later. Along the lines of the trough box idea, I'm considering pulling conduit via the center large knockout (reduced as appropriate) to a large attic box so that the wall need not be torn open again!
 
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