Knockout Plugs

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jerm

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Tulsa, Ok
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I had an apprentice tell me today that an inspector (I won't name him, but he is the chief electrical inspector in Tulsa, if you're out there reading this feel free to defend yourself!) told him that knockout seals have to have the smooth part on the inside of a junction box, so that the 'teeth' are on the outside. He said it's because of a code (the apprentice couldn't give the article number, go figure) that says something about sharp objects inside a junction box, and how they'd have the potential to cut into a wire.

Which way to you install these, and have you ever head of any nec requirement for doing it one way or another? I'd love to hear your thoughts on this.
 
I do not believe that this is true at all. The edges of the KO plug that you pictured isn't even sharp. That being said, I have installed them inverted but only when the situation warrants (ie- snapping one into a box that has been drywalled into a stub cavity already).
 
I would say, install to manufacturer instructions. If there are no instructions (I have never seen them for KO closures) then either way is OK. 110.12(A) is silent on this.
 
"I usually install them facing in but I also usually flatten the teeth out against the box"

Me too, and flat'em out.

What do you do when you have a weather proof KO seal. Does that wingnut go on the inside or the outside? Always put the wingnut on the inside, sharp ole screw or not! Sounds like a conundrum here, kids.

Happy New Year Everyone and Best Wishes
 
I agree that they aren't sharp at all, and I do flatten them out to make sure they stay in tight anyway.

Maybe some day I'll run into this guy and he can tell me what article he thinks I'm violating.
 
I install them face in, which I think is the proper way to install them but I have installed them either way.

gus
 
314.17(A) Simply states -

Openings to Be Closed "Openings through which conductors enter shall be adequately closed."

If the inspector is concerned about leaving any of the tabs sticking up, ask about how do they address all the push through gear for light and plug connectors out there already? The blow-and-go AC and some MC connectors are all this way.

I had an apprentice tell me today that an inspector (I won't name him, but he is the chief electrical inspector in Tulsa, if you're out there reading this feel free to defend yourself!) told him that knockout seals have to have the smooth part on the inside of a junction box, so that the 'teeth' are on the outside.

Careful here! Wouldn't be the first time that an apprentice has got the story wrong...next time he sees the inspector, have him contact you, approach him with a little tact, and I'll bet the story is different. If not, he needs a trip to the website, and a little plumbed up.
 
Rockyd said:
...an apprentice has got the story wrong

er, especially this one... Maybe I'll call up the inspector after the holidays and get the story firsthand. But his version was that he had to change some when working with another journeyman on another (not my) job site.

(the apprentice in question doesn't have a computer so the chances of him reading this are pretty durn low... so I can badmouth him with impunity...)
 
I never flatten the teeth on then ones - then again I neither stock or would install one if handed to me....

I use the little GB type with the toggle screw on them. The one time I attempted to flatten the teeth on a pop-in one I gashed my finger - I never picked one up again.
 
e57 said:
The one time I attempted to flatten the teeth on a pop-in one I gashed my finger - I never picked one up again.

Humm... maybe you were just doing it wrong! I use a flathead screwdriver and hit it with my nine-kliens to flatten them puppies out... Never seen these GB toggle-type of which you speak.

Get back up on that horse! If I abandoned a product or tool every time I bleed, I wouldn't have much to work with! I loose pints of the red stuff to this profession!! :)

(I gashed open my thumb earlier in the week using my utility knife to strip #2!)
 
As mentioned these things aren't even sharp. Anyone who's ever worked in a commercial panel will tell you that there are multiple metal edges within the panel that are very sharp. Much sharper than a KO seal. Someone is off base with this one.:rolleyes:
 
e57 You are suppose to use a screw driver to flatten them not your finger and no bounce.

I almost always flatten them.
 
Best way to handle inspectors is say nothing till your asked.Then answer as little as you can.If they suggest you have a violation ask for the number and get out code book.After your known to do this they carefully pick battles.If they are right no problem but if not ---------------- never back down 1 inch
 
So it's you's guys who flatten out the teeth on these. Makes it a real PITA to remove them. Are you's guys the same one's who use the wirenut attachment and twist the wires all the way to the conduit, too?
 
paul said:
So it's you's guys who flatten out the teeth on these. Makes it a real PITA to remove them. Are you's guys the same one's who use the wirenut attachment and twist the wires all the way to the conduit, too?
Nah, I use sta-kons to really make it tough on the next guy.:rolleyes:
 
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