Can plastic and metal conduit be mixed in a single run?

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Old 08-25-11, 07:07 AM
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Can plastic and metal conduit be mixed in a single run?

I'm running a 1 in. pvc conduit on outside of house for a subpanel in lower story shop. I'm unable to find a 1-in offset connector in the local stores. I notice that there is a metal offset in the store. I could use that, with two female plastic adapters, but will code allow it?
Thanks.
 
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Old 08-25-11, 08:14 AM
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No. You will somehow need to bond the offset. You can, however use a grounded metal box.

Did you check supply houses for the offset?
 
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Old 08-25-11, 08:28 AM
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I did find at least one source online, and two electrical supply houses in town. Thanks for your reply.
 
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Old 08-25-11, 09:26 AM
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Actually you CAN intermix plastic and metal BUT the metallic conduit MUST be bonded to the equipment grounding bus of the supply. Since that is usually an onerous procedure it is much easier to simply use plastic throughout. Also, if you intermix you obviously cannot use the conduit alone as the equipment grounding conductor.

What you CAN do if you have a heat gun is to heat the plastic conduit and then gently bend it to the offset needed. It takes a bit of practice to accomplish without flattening the conduit through the bend but it is an acceptable method.
 
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Old 08-25-11, 10:12 AM
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Yeah it's pretty easy to make a pvc offset. Put on leather gloves, heat the pipe slowly with a heat gun (not hair dryer) or carefully high over a clean flame like a propane torch. Car exhaust works on small pipe. Once the plastic softens a little you can form it into an offset by running your hand down the pipe and introducing the bend you want. Hold it still until it cools and you've got a custom offset.
 
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Old 08-25-11, 06:38 PM
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I have used a torch, but it's a slow process and you have to be careful not to burn the conduit. The easiest way is to use a "hot blanket" for a professional looking job.

http://www.gardnerbender.com/pdf/ins...structions.pdf
 
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Old 08-25-11, 10:14 PM
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I've made odd angles and offsets by filling the piece with compacted dry sand (with a couple end caps fitted on) then putting it in the oven at 250 for 20-30 minutes (or until it is totally flexible). Then I form the angle on a jig (a board with a couple nails in it) and let it cool. Then just dump the sand and you're ready to go. The sand keeps the pipe from collapsing when you bend it.
 
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Old 08-29-11, 04:12 PM
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Here's another method for bending PVC. I've used it and it works great.
No, I own no stock in this company.
The way I use it is to attach a string to the "coil" and slide it down the conduit until the center is where your bend will be.
Carefully warm the bend area with a heat gun and when soft enough, start bending.
When the conduit cools, pull the "coil" out using the string.
It's very similar to the sand method but less messy.

1" Pipe Viper easily bends pvc conduit
 
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Old 08-29-11, 04:58 PM
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A BBQ grill works well in a pinch.
 
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Old 08-30-11, 06:48 AM
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Hey, Scott, BBQ grill.....good idea! You're gonna be out there anyway, right? It's summer. Or it's a holiday like Thursday. Cooler next to the grill, you're set.
 
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Old 08-30-11, 07:07 AM
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Lunch, and some nicely bent PVC, what could be better?!
 
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Old 08-30-11, 09:09 AM
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Just don't end up with a footlong piece of PVC on a bun!
 
 

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