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metal junction box - difficulty accessing/opening knockouts

metal junction box - difficulty accessing/opening knockouts

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  #1  
Old 03-06-18, 11:44 AM
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metal junction box - difficulty accessing/opening knockouts

See attached. I'd like to attached some 14/2 Romex to this junction box and add a new light to the hallway below. This view is from top/attic.

See pic.


item A on pic
- despite some significant effort, I can't pop this knockout open. now I'm concerned - should this not open? not a knockout, just looks like one? i tried from above and below...with some serious tapping

item B on pic - curious - what are these two small holes? one looks damaged/dented - reason for concern?

item C on pic - these are running out of each connection on this and other adjacent junction boxes - are these stray grounds?

Thanks in advance for any tips.
 
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  #2  
Old 03-06-18, 11:47 AM
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item A on pic - despite some significant effort, I can't pop this knockout open. now I'm concerned - should this not open? not a knockout, just looks like one? i tried from above and below...with some serious tapping
It will come out with more tapping. Some are more difficult to pop out than others. Use a flat bladed screwdriver and work your way around.

item B on pic - curious - what are these two small holes? one looks damaged/dented - reason for concern?
These holes/slots are to insert a flat bladed screwdriver in order to pry the knockout open

item C on pic - these are running out of each connection on this and other adjacent junction boxes - are these stray grounds?
No clue.
 
  #3  
Old 03-06-18, 11:50 AM
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A - put a flat head screwdriver at the edge of the KO and give it a firm whack with a hammer. This will break it loose enough to twist out with needlenose

B - That box entrance is already used by the armored cable. One of the opposite side of the box might be open. Stick a flathead screwdriver in the slot and lever out the KO. Once loose, twist out with needlenose

C - It looks like bonding strap for the armored cable.

That box looks like it will be pretty full to add an additional cable. Replacing with a larger box would be a good idea.
 
  #4  
Old 03-06-18, 11:50 AM
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Use a flat blade at the edge with a mallet.
 
  #5  
Old 03-06-18, 11:51 AM
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Thanks! Do you suggest tapping from inside (below) or outside (above)? I was really hammerin' at this thing, but I will revisit.

Do you think the damage to "B" is a concern?
 
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Old 03-06-18, 11:54 AM
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From the outside. Follow the same direction the KO was stamped from the factory. And don't tap - give it a good whack. You have to fracture the little remaining strip of metal that holds the slug to the box.

B- Not a concern.
 
  #7  
Old 03-06-18, 12:55 PM
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Originally Posted by ibpooks View Post
From the outside. Follow the same direction the KO was stamped from the factory. And don't tap - give it a good whack. You have to fracture the little remaining strip of metal that holds the slug to the box.

B- Not a concern.
For B, I have personally done this a few times and I always went from outside. You dont want to tap B at all, you need to use a large flathead screw driver (like a 12-14 one) and simply stick the tip in and bend it outwards gently. You shouldnt put too much torque on it as in dont do rapid quick high force pulls but rather gradual and gentle moves.

Te other bigger knockout on the side needs to be tapped from outside and from the edges only.

That being said, I m not sure if anyone else pointed this out but you already have both Bs using BX armored cable. That means romex in those is not going to work. The BX uses a different connector inside the box than romex. UNLESS whoever installed the box used non metallic cable connector for BX but even then due to the difference in diameter your romex wont be tight enough. I personally would go with the larger knockout there and use romex knockout connector.

Lastly, I already see 3 cables going in there, its a small octagon shaped box. I m not an expert but if it were me, I would consider redoing that box all together, it will be too crowded in there with the romex.
 
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Old 03-06-18, 02:55 PM
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B cannot be used as the knockout. The clamp is already being used for the cables below.
 
  #9  
Old 03-06-18, 03:39 PM
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Thanks all for good info. I was able to persuade "A" open and attached Romex with an NM connector.

My only remaining question - the new Romex has a Ground, but nothing else in this old junction box is grounded. Thoughts on where to attach the Ground? The Ground on the other end of the Romex should be easy, as it'll attach directly to a light fixture.

Thanks,
Craig
 
  #10  
Old 03-06-18, 03:46 PM
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Originally Posted by CSPierce View Post
Thanks all for good info. I was able to persuade "A" open and attached Romex with an NM connector.

My only remaining question - the new Romex has a Ground, but nothing else in this old junction box is grounded. Thoughts on where to attach the Ground? The Ground on the other end of the Romex should be easy, as it'll attach directly to a light fixture.

Thanks,
Craig
Most likely the metal jacket lf those other wires act as ground. Only way to find out is using multi meter and measuring hot to ground. If you havent used MM before i would practice first. I usually use an extension cord for this, one probe to hot terminal of extension cable another probe to anywhere on metal box. If you read 118-120, you are good. But please be careful.

If the above is true, simply use a ground screw and attach ground wire of romex to the box.
 
  #11  
Old 03-06-18, 04:34 PM
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Thank you. I tested with the multimeter meter as you described, with good results. My multimeter is not too precise, but readings seemed to be neared to 140 VAC. I tested in a few near outlet ground, and the measurement was identical.

As for the Ground wire - I have one empty screw on the box, but it's not recessed. It's nearer to the bottom. See attached. Does this work? See pic - red box.
 
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  #12  
Old 03-06-18, 04:38 PM
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I'll add - I did not see any threaded holes to add a screw. I have seen ground screw terminals on the brackets used to hang lights. Is that an option?
 
  #13  
Old 03-06-18, 04:58 PM
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That is an old box and will not be tapped for an extra ground connection.
Use any available screw for ground.
 
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