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View Full Version : How Many Romex Cables through one Clamp ?


Milo Dolezal
Jul 13, 2008, 12:42 PM
Hi There...

So I installed my new 200 Amps main service panel. Now, I have 40 romex cables that will be connected inside the panel. However, the panel has only 7 cut outs for clamps on top and bottom. One is 2", 3 are 3/4" and 3 are 1/2".

My question is: can I run romex cable in bundle through the 2" clamp ? Like 20 - #14's ? Same with 1/2" and 3/4" ?

Thank you

KISS
Jul 13, 2008, 12:53 PM
There are dual clamps available as well as adapters that adapt larger knockouts to smaller ones. Finally, you can either punch or use a Unibit to make knockouts.

For the initial hole try to use a bullet bit by Black and Decker or a pilot point bit. They don't do stupid things like make triangular holes and pull your drill into the box when you break through. Use a drill stop (a collar around the drill) to reduce the depth of penetration.

stanfortyman
Jul 13, 2008, 02:01 PM
You have a new panel with ONLY those knockouts?? What kind of panel is this?

Most typical two-screw NM connectors will accept two (sometimes three) cables. The carton will tell you.

Milo Dolezal
Jul 13, 2008, 02:12 PM
Stan40Man: I have Murray 200 Amps. It is "skinny" panel split into halves, lengh-wise in the middle. Left side is enclosed for clock and main supply from the street. Right side is the side with breakers. I have 7 knock-outs on top, 7 on the bottom. There are 2 on side, but they are covered by framing.

stanfortyman
Jul 13, 2008, 03:22 PM
Ohhhh, it's an outdoor panel. That explains it.

hkstroud
Jul 13, 2008, 05:33 PM
KISS and Stan,

This is a question not a statement.

Wouldn't drilling or making you own knock out holes amount to modification of electrical equipment and void its "approved" rateing or status?

Just wondering.

stanfortyman
Jul 13, 2008, 05:38 PM
Actually no, not at all.

Most commercial and industrial panels have NO KO's at all. You have to drill/punch everything on site.