what clamps to use in my new panel?


Old 10-04-15, 03:19 PM
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what clamps to use in my new panel?

Tomorrow I'm replacing my entry panel.

My old panel uses these clamps:

The guy at Home Depot says I should only be using these clamps:

Is that true?

I think the ones on top will allow more conductors through a single knock-out, so I'd like to stick with those. I'm having a hard time finding the maximum number of conductors allowed, though. Even the manufacturer data sheet isn't specific. How do the pros know the max number of conductors?
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Old 10-04-15, 03:47 PM
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How many cables, what type, size and how many holes available in the new panel?
For standard #12 and #10 NMB cables, I used nothing but these before I retired.
I usually put 2 #12 nmb cables in one of the 3/8" connectors.
These are plastic, so there is no danger of over-tightening, or short circuit to the panel enclosure.
These type will stay in the hole and secure the wire.


They also come in a 3/4" knock out size. For the big cables, #2, 4, 6, I would use the standard romex connector that you show from Home Depot.

I'm not trashing Home Depot in any way, but a lot of the people who work in the electrical department are not always "up to snuff" as we old timers say.
Old 10-04-15, 04:07 PM
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I've never seen those wire connectors in the top picture used in a panel. Those look like the basic clamps you get with appliance power cords.... mainly dryers.

You can use the connector in your second picture or the plastic ones in the previous post or my favorites for the top of a panel..... diecast duplex connectors.

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Old 10-04-15, 05:24 PM
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Any code/safety issues with keeping the old 2-piece wire connectors I've got? I agree that they're not used in modern panels, but they're still ok for connecting wire to a metal enclosure, right?

For the duplex connectors, do you just run one #12 or #14 wire into each? The plastic connectors look appealing, but that's another trip back to HD at this point.

My new QO panel has tons of 1/2" knockouts. Most of my circuits are #12 or #14. I've also got a #4, a couple #6, and a #10. Looks like the builder electrician did two #12 or #10 per 1/2" KO and then 3/4" KOs for the larger wires.
Old 10-04-15, 07:19 PM
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I've decided to ditch the old 2-piece connectors. They aren't rated for multiple conductors anyway.

I have a 70A cable running to a subpanel for my A/C units. On the cable is written: 2-4 1-4 TYPE SE CABLE STYLE U TYPE XHHW CONDS

Which of the following two clamps should I use based on the manufacturer description:

1": Fits NM Cable: #14/2 to #6/3 AWG or #3/10/3 AWG or Flex cord .450 to .730 inches diameter.

1-1/4": Fits NM Cable: #6/3 to #2/3 AWG Flex cord .800 to 1.350 inches diameter or SE cable 3 conductor or 3#1/0 min; 3 conductor or 3#2/0 max.
Old 10-05-15, 07:55 AM
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I'd probably use the 1" KO and clamp on the #4 SEU.
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