Packed conduit from breaker box to attic

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  #1  
Old 05-26-04, 10:12 AM
gdesignr
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Packed conduit from breaker box to attic

My house has a fairly new 200 amp GE breaker box on the outside of the house next to the meter. There is a 2" conduit that runs out of the top of the breaker box about 3 feet to the attic where it goes through the wall. All of the wires in the house run through that conduit to the breaker box.

Most of the wires in my house have been upgraded to new grounded wire, but there are a few rooms that still had old rubber coated black wire without the ground wire. I've been pulling new wire to replace this old wire in a bedroom I want to convert to an office, and I want grounded outlets for my computer.

After some work I was able to pull the old wire out of the conduit, but I can't pull the new wire back through. It is too tight in there. The big 8 gauge oven cable takes up about half the space, leaving about an inch for the rest of the house wires. It's packed. I would think that this type of setup would be fairly common, so how do people normally fit all those wires in there? Half the breaker slots are empty, so the breaker box is made to hold twice as many wires, but there is no way they would get through that conduit.

The hole in the top of the breaker box looked like it was 2 1/2 inches across, so I went to Home Depot to see if they had 2-1/2" conduit, which would give me a little more room, but they do not. Other ideas I have include running a second conduit, although there are no other punch outs on the top of the breaker box, or trying to coat the wire with soap or something slippery which might help it through.

Any suggestions?
 
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  #2  
Old 05-26-04, 11:35 AM
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Location: welland ontario
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That conduit sounds seriously over filled. After 9 conductors you need to start derating if the bundling is over 24".
Was this installation inspected?
 
  #3  
Old 05-26-04, 12:15 PM
gdesignr
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conduit and bundling

I counted them up, and there are 16 wires running through the conduit. I bought the house about 2 years ago and it was already there, so Im not sure if the initial install was inspected, but I did have a bathroom addition and laundry room move done with a electrician and inspector and they didn't seem to have a problem with it....

Regardless, I would be happy to split this into 2 conduits, but the top of the box only has one hole in it. I could maybe run it to the punch out on the bottom left side, but then I'll have to deal with another elbow and a longer length of pipe.

I'm wondering what is the typical way of running the wires when the breaker box is on the outside of the house? I took a quick look at my neighbors houses and they seem to have a similar setup... just one conduit coming out of the top of their breaker box to the attic.
 
  #4  
Old 05-26-04, 01:18 PM
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Location: Chicago
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You mean 16 NM-B wires? Each with 2 (and ground)?
Unless you can access the back of the box and pull them through the wall you'll have to run a conduit off the side, using a LB fitting.
 
  #5  
Old 05-26-04, 02:27 PM
gdesignr
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wires and conduit

Yes, that's 16 NM-B wires.... all but 2 or 3 now have 2 wires plus ground. 2 of them are still the old ungrounded wire that I'm trying to replace. They go to the guest bedroom and dining room. One of the 16 is the 3 wire plus ground cord for the oven. It's packed.

I should be able to run a second conduit off the side. It's a concrete block wall, so I can't really run through the wall. I basically have to go up to the attic. The hard part is that it's in the part of the attic closest to the eves where there is only about a foot or so of headroom. I'll mostly have to fish the wires over to it.

Thanks for the help. Let me know if you have any other ideas or insight into how other people handle this.
 
  #6  
Old 05-27-04, 11:31 AM
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Location: welland ontario
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16 cables with 2 wires equals 32 current carrying conductors. Since 9 is the limit (you can only put 8 do to cables can't be split) before derating you will need to add 3 conduits just to fix your present wiring. If you want to add more cable then you need another conduit.

I could be wrong on this. This could be a situtation where derating doesn't apply. Some one will come up the the proper code for this.
 
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