Plug KO hole in electrical box from inside?


  #1  
Old 05-27-19, 07:06 AM
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Plug KO hole in electrical box from inside?

Hi,

I’ve got an existing electrical “switch” box in a wall from which I removed one, no longer required, BX wire (there are two remaining required BX coming into the box specific for lighting in the room). Now I have a knockout opening in the box which I know has to be closed up.

The box is nailed to a stud and I was looking for a way to close that open knockout from the inside of the box without having to extract the box from the wall.

Any thoughts?

Thank you!
Andrea

 
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Old 05-27-19, 07:17 AM
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KO seals

You can either use a snap in metal KO plug, assuming you feel like the tangs capture the hole we’ll, or get a 3-peice KO seal (has a crossbar and machine screw that you fit through the hole and tighten) may be a bit of a challenge to tighten the screw from inside the box, but it is doable.
 
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Old 05-27-19, 10:52 AM
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If you're talking about the KO where the clamp fits over it..... there is no seal for that.
It's usually an oblong hole. I use metal foil duct tape to cover those types of holes.
 
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Old 05-27-19, 12:26 PM
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Regarding the 3-piece seals, I would need access to the outer part of the box to install, from what I can gather from the looks of these particular types of seals. I only have access to the inside of the box.

Aren’t there any rubber type seals that I can push into the knockout from inside the box?

Will try to install the standard metal k.o. covers....
 
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Old 05-27-19, 12:33 PM
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PJMax,

This hole is perfectly round...

Andrea
 
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Old 05-27-19, 01:37 PM
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Ok....so use a generic KO seal. It can just snap in place from inside the box.

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Old 05-27-19, 04:24 PM
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You people need to listen and read these post better. I explicitly said either use a snap in KO seal, as somebody was so nice to include a picture of one, or use a three-piece (w/ clamp) and install it from the inside of the box. Rubber seals are not code correct, metal foil tape is not code correct Neither of those will keep a fire inside the box. Half the stuff I see on this post really requires an electrician, not a do it yourselfer. Good luck. I’m done.
 
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Old 05-28-19, 06:42 AM
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I know what a KO snap-in is, no pic was required here, but much appreciated. I did try to install one, but it is getting in the way of the internal clamp, so I can’t fully secure the BX coming into the box.

I have no intention of installing anything, unless an experienced electrician here, advises me that I’m code compliant. What I’m not entirely aware of are the various methods used by experienced electricians to solve problems, that are within code limits. So I’m throwing questions out there, but understand that I don’t intend to endanger myself. I’m not a risk taker, but I’m very eager to learn and I understand working with electricity can be very dangerous and I never work with live wires!

At this point, I’ll be opening the wall and probably changing out the box and the old BX, which upon further inspection, appears to be damaged.....

Andrea
 

Last edited by Andrea B; 05-28-19 at 06:44 AM. Reason: Want to add info
 

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