Old breaker box "extender" for conduit?

Old 01-09-10, 01:03 AM
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Old breaker box "extender" for conduit?

Hi everyone,

I hope you can help me out. I've been racking my brain to come up with some kind of solution to this.. (this is a long story, but it goes somewhere! )

My mom bought a very nice house in Kansas. It was built in the late 30's by a very wealthy man, and no expense was spared as far as materials. It is all brick and poured concrete. Even the interiors (this house was built to be the only thing left standing in a killer tornado!)

However, the electrical system is a nightmare. It is all 2 prong outlets (she bought out the general store of their supply of adapters), and it has the old asphalt/cloth wire (all the splices are soldered and taped). The original breaker box was one of "THE" first breaker boxes (Square D MultiBreaker), and it is encased in concrete. Over the years, there had been three additional breaker boxes added onto the system, but the last one was apparently done sometime in the 70's because there is aluminum wire on those branches. Also, there is only 100A service, and there are a few instances of overfusing wire, and all of the original circuits of the house are on 4 breakers. (all outlets, all upstairs lights, all basement lights, and kitchen)

Now, the major upside is that this house is 100% conduit. So pulling all new 12ga THHN has been a snap. Tape the new to the old and yank. I have also split many of the circuits so like the toaster and refrigerator don't trip the breaker..

I have also installed a new 200A panel, and ran 2/0 out to the meter, so I can have the service upgraded down the road. With the fact that 3 of the existing breaker boxes were added on, I was able to eliminate them easily. I stripped them out and used them as junction boxes, then ran conduit back to the new panel.

However, this big long story brings me to my question..

The 'original' panel, being as it is encased in a concrete wall, is a puzzle. For the amount of conductors that I now have (4 original 2-prong circuits are now split into 12 grounded), I can't use the original 3/4" conduit that carried the original 8/3 feeds (even if I was able to pull those wires out, which I can't - the insulation has melded to the conduit). So I have to run a new 1" conduit from this old gutted breaker box to the new panel. I can't go through the back of the box, because it would be in the middle of a bedroom wall. I can run it up the front, since it's in the basement stairwell, but how to make the transition has me stumped.

I've been looking for some kind of metal or PVC box that I can cut the back out of and bolt it to the existing box, then drill in for the conduit, make the connections, and slap the cover on. But I can't find anything that's the right size (it's approximately 8x12) and isn't cube shaped (I only need like a 2" depth), and also isn't absurdly expensive for what I'm going to do with it.. Ive priced junction boxes and control cabinets that are the right size that go for several hundred dollars..

I just need to do like you would with an octagon box extender or a Plugmold hidden-to-surface transition. Doesn't need to be fancy or expensive, it just has to cover the wires.

Does anyone here have any ideas on what I could use?

Thanks in advance!

Old 01-09-10, 02:57 AM
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If you're just looking for something like this it's 12x8x4, $22.00
from Enclosures Products

Some may say this wouldn't be "listed" but, I don't see it being that big of an issue. I've had to make plenty of "field" modifications with no problems.
Old 01-09-10, 08:29 AM
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I was going to suggest having a steel coverplate fabricated for the box with a hole for a CB ell but Wirenuts idea is better.
Old 01-09-10, 09:20 AM
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Perhaps you could post a picture?

WP, could you elaborate on the transition into the pull box? The way I am envisioning the pull box is mounted above the top edge of the flush panel enclosure. How were you going to connect the two? A pull ell could not be used as the cover would not be accessible.
Old 01-09-10, 05:18 PM
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Wow thanks for the quick replies! Wirenut, that is exactly what I'm looking for, thanks!! I'm not real worried about listings. It'll do what I need it to, and it'll look a lot better than it does the way I had to leave it to come home (conduit just right angles into the front of the box).. I'll be going back there beginning of Feb, so I'll get that box ordered and let you know how it works out.

Ray, I had considered that, but there's just too many connections to make in a CB, and I wouldn't be able to remove the large cover without having a flex joint/union in the conduit.

pcboss, I will be cutting the back out of the pull box, and mounting it 'on top of' the flush mount box. Just like you would with a backless octagon box when you need more box capacity, or to add a surface mount conduit to a flush mount box.

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