4 inch pancake box wiring questions


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Old 03-29-17, 11:02 AM
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4 inch pancake box wiring questions

We have a beautiful house built in the 1920s. I was changing over a light fixture when I found that the ceiling of the room is wired with rubber wrapped 12(?)gauge wire that goes into a metal pancake box attached to what I believe is a ceiling joist. Based on current code I think it's overfilled as it has one pass through common wire (that goes in and out without any termination), the common line, and 2 load wires that are spliced together (I'm not sure why there are 2 loads). The visible insulation appears to be in good condition. If I'm just changing a fixture I know I'm not required to make this code compliant. My understanding with the reason for the code is excess heat causing damage to the conductors leading to insulation failure --> fire. The fixture is a chandelier that will be 3 feet lower with LED bulbs so heat and wattage should be much better than it ever was before. My questions are 1) can I cut the pass through wire and wire-nut it? I figure yes but I wanted to make sure. 2) the box covering the ceiling (from the fixture) has ample room to leave wires in it, to my mind that would be safer from a heat standpoint. I don't know if that's code compliant or stupid for a reason I'm not aware of. 3) replacing the pancake is possibly doable but I'd then have to cut into the wood rafter to make room. I'd prefer not to do that out of concern for opening up a can of worms. Do I need to do this? 4) Current wiring does not have a ground line, if I attach a ground to the metal box does that provide any safety gain? Thanks for your help. Elmo
 

Last edited by Elmo33; 03-29-17 at 11:30 AM.
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Old 03-29-17, 03:26 PM
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Welcome to the forums! I am not sure what you would gain by cutting one of the wires and nutting it. Doesn't it go somewhere? You are grandfathered with what you have as long as you don't change the wiring. I would suggest removing the pancake box and using a saddle box which has a higher conductor count and would alleviate the problem you are having. In some localities pancake boxes are not allowed, so changing yours may be a good idea. I know it says a 24 pack, but you can get them individually for about $8 Raco 4 in. Round Non-Metallic Ceiling Box, 2-39/64 in. Deep (24-Pack)-7120-1 - The Home Depot
 
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Old 03-29-17, 03:26 PM
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When you say "pancake" box, you're referring to one of the ultra shallow ones (1/2" deep), right?

If so, then yes, by code it's already over capacity by one wire (assuming there's no ground in there). Those boxes are just over 6 cuin, so you're only allowed 3 #14 conductors. The one that passes straight through only counts as one now, but if you cut it, it becomes two.

What you can do is install a "saddle box". It's a fan-rated PVC box that straddles the ceiling joist. It's still technically a pancake, because it still only sticks out 1/2" from the face of the joist (so it will still sit flush with the ceiling), but it has 12 cuin capacity.

<img src="https://images.lowes.com/product/converted/786358/786358003817lg.jpg" width="276" height="276"/>
 
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Old 03-29-17, 07:17 PM
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This is how it looks. The one part that I didn't explain was that the light fixture has a long steel bar that is mounted flush to the ceiling. The way the wires run out of the box is directly in the path of the bar with very little room to bend them. If I cut and re-connect the cut wires I can put them through the bar (by drilling a hole in the bar).
 
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Old 03-29-17, 07:20 PM
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Size:  37.5 KB Here's another image. Sorry for the double post couldn't get both into 1 post.
 
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Old 03-29-17, 08:44 PM
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Oooh it looks like you're sorta stuck there.. Technically that mounting nipple counts against the capacity as well (1 conductor) so yeah.. But being as it's conduit you can't use the saddle box either unless you're willing to cut into the plaster and repair it (will look really ugly) to cut the conduit.

It's not as overloaded as I've seen, but you just do what you need to. It's not really going to change anything at this point. Just be careful with that wire, the rubber is very brittle and if you mess with it too much you'll crack and crumble it right off. I just pulled a ton of that crap out of my house.
 
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Old 03-31-17, 07:59 AM
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It would appear that looped conductor must be going in and out of conduit,in which case you won't be able to change it easily,PVC boxes won't work, have you checked to see if the box is grounded,use a analog meter to test Hot to the box.
Geo
 
 

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