Wires Doubled

Is it acceptable to use one knock-out opening and clamp for 2 wires going into a panel?
How about 3 or 4 wires going through a hole drilled though a joist?

Nothing wrong with that in my opinion.

It sounds acceptable…

Cables must be secured to the panel w/clamps used in accordance w/there listing. Some clamps will accept two small cables;a bundle through one clamp is a common defect. i dont see a problem with the wires going through the joists they got to get to where there going there some how

Depends on how large the hole in the joist is as to whether
it is ok or not.

The hole in the joist was probably about 3/4". There was no way another wire would have fit in addition to the four that were in there.
Sometimes you see equally spaced holes with one wire each; nice and neat. Other times only a few holes with multiple wires. That made me wonder.

The romex connector that is used has on the package the specs for wire size and number combinations. Usually more than two in any given connector is unacceptable.

I have read the packages of several Romex clamp fittings, and they were listed for up to 2 Romex cables, 12 or 14 AWG. As to the number of cables that can pass through a hole in a stud, I believe that if you can get the cables through the hole without damaging them, it is OK. There is no limit per se. Of course you have to allow 1.25" clearance to the edge of the stud or provide a nail plate

I have built homes in six states, all only allow two romex through a 3/4" hole, even if they are loose. More wires require an additional 3/4" hole for the third romex, this was developed to keep everything somewhat centered in the studs, and less likely for a short that might create 220 from two 110 circuits. Even one romex nmb-14 requires a single 3/4" drilled hole. Only low voltage wires can use holes smaller than 3/4". A lot of non pros use a 5/8 or 1/2 hole, and the wire is not pinched , but it is the tell tale sign that a pro electrician did not do the wiring. Where is the electrical guru ?


As long as the panel opening is not compromised and it contains a grommet or bushing at the penetration area…

Wires can penetrate holes in joists. Simply make sure that the drilled hole sizes do not exceed code…

I am going to take exception to the parts called out for in Davids post. Bushing and grommits would not necessarily secure the cable to the enclosure. The proper fitting would be a cable connector.

Like others have said it needs to be rated for both the cable size and number of cables.

Thank you, Jim.

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