Tiny metal box on bathroom vent

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Old 12-12-11, 07:42 AM
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Tiny metal box on bathroom vent

I bought a Panasonic bathroom vent for a new bathroom I'm building. It has 3 electrical connections: fan, main light, and night light. I know how to wire these connections but I was really surprised to see how small the built in electrical box is. Here's what it looks like:



The dimensions of the box are 2.5 x 3 x 1.75 = 13.125 in^3. By the time I hook up one 14-3 and one 14-2 I'm going to have 11 conductors, a bundle of grounds, and 5 wire nuts. I need a box almost twice that size to accommodate that many conductors. Are there any tricks to make this work?
 
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Old 12-12-11, 08:37 AM
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Read the instructions that came with it?
 
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Old 12-12-11, 08:55 AM
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Use ENT (Smurf) plastic flex conduit and individual wires. I'd suggest you bring in power at the switch. That way you have only 5 wires to the fixture.

 
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Old 12-12-11, 10:34 AM
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The instructions don't say anything about the electrical, probably for liability, but the problem isn't that I don't know how to wire it. The problem is that the box size is too small to be up to code for the number of conductors I need to use.

The flexible conduit is a good idea for getting rid of the romex sheild that would be in there. And I was definitely planning on putting power at the switch to use the minimum number of conductors in the box. I'm still pretty sure the box size isn't up to code for minimum cu. in. though.
 
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Old 12-12-11, 10:38 AM
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Provisions in the code do not necessarily apply to a manufactured item. The item HAS been subjected to testing by a NRTL, most likely Underwriters Laboratories, and they have deemed the connection box to be adequate.
 
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Old 12-12-11, 10:41 AM
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I'm sure they can have such a small box because it's an engineered and certified device so the codes do not apply. Besides, how you make all the wire fit is your problem. Making the electrical box larger would cost them money.

As a side note I would love for them to de-burr the sheet metal used in those things. I don't think I can install one without drawing blood at least once. Usually it's when I'm cursing while trying to shove all the wires into the enclosure and get it screwed shut.
 
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Old 12-12-11, 11:21 AM
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There is no need to use two separate cables (14-3 and 14-2) to wire this fan. Use individual wires in conduit as Ray suggested. The installation instructions that come with Panasonic bathroom vents indicate that. I'm not sure what model you have but the ones I've seen have a figure in the installation instructions that show the j-box being fed by conduit containing 5 conductors and a safety ground.
 
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Old 12-12-11, 01:14 PM
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You'd have to go to a supply house but they also make 4 conductor plus ground NM-b. ENT probably cheaper and easier to obtain.
 
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Old 12-12-11, 03:55 PM
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Thanks guys, I didn't realize the box size code didn't apply to manufactured products. I'll be fine getting wires in, I think. I was more worried about inspection.

Pilot Dane - I know what you mean about those things being sharp. My hands are all cut up after hanging recessed light housings!
 
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Old 12-12-11, 06:58 PM
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That wiring compartment is huge compared to some of the bath fans I have wired.
 
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