Wiring question

[ed_denu]

I've started building an oven and have a question concerning wiring. I've mounted the elements on the side walls attached to metal electrical boxes as is common to the oven's I've seen. I was contemplating running conduit with high temp wiring from the element box, thru the insulated wall into another metal electrical junction box outside the oven. From this point on I would like to use 'regular' wire.

My question is how do you keep the conduit from becoming a path for the heated air running all the way back to the temperature controller(PID), SSR, etc.

One option would be to leave the wiring exposed(outside of conduit) within the insulated walls. Another would be to stuff insulation into the conduit? How has everyone addressed this?

[chromo]

Not much you can do about conduction heat. If the conduit/pipe is metal it will conduct some heat if in contact with the heated area. You could try to isolate the conduit from the heated area inside best you can with some insulation. On the outside of the oven you could run the conduit to a heatsink to remove most the heat before it gets to the control box. Outside the oven is probably not a big worry, the conduit should cool off decent on it's own if exposed to open air and runs any distance.

Stuffing the conduit with some loose insulation on the oven side should stop any airflow from heating it up, block convection flow or air leaks to outside of oven etc..

[chromo]

OH, and my thought using conduit is basically a straight shot out of the oven through the wall and run the conduit outside the box. So if I had a 4" wall a short piece of conduit would run straight out, then if a 4' run to the control box the conduit would be exposed 4' to open air.
That would make it easy to work on if I ever wanted to run more wire or replace wire.

If I needed to put the conduit in the wall for some reason, then of course it would be on the outside of the insulation next to the outer skin. With decent insulation the conduit should not gain much heat but lose most of it through the outer skin of the oven.

In any case, only the DIA. of the end of the conduit should be in direct contact with inside of the oven if ran straight through the wall and stops there. If you run conduit all the way to the elements inside the oven, like centered, then that run will gain more heat and not much you can do about that.

[ed_denu]

I might just go with a little insulation stuffed into the conduit on the oven side. Thanks

[hbracing]

my 2 cents worth! just drill a small hole and run the heat resistant wire to a pulling "L" or box out side the oaven and convert it to regular wire. Debur the hole and when you get the wire where you want it add a blob of high temp caulk in the hole that the high temp wires are running through in side the oven. I would not use conduit to go to the outside of the oven as that would transfer heat. Just run the wire thru the insulation and blob the hole on the outside wall where the wire comes thru...DONE....No heat transfer and a nice seal

[ed_denu]

Originally Posted by hbracing

my 2 cents worth! just drill a small hole and run the heat resistant wire to a pulling "L" or box out side the oaven and convert it to regular wire. Debur the hole and when you get the wire where you want it add a blob of high temp caulk in the hole that the high temp wires are running through in side the oven. I would not use conduit to go to the outside of the oven as that would transfer heat. Just run the wire thru the insulation and blob the hole on the outside wall where the wire comes thru...DONE....No heat transfer and a nice seal

Thanks - This is close to one option I had considered. Using hi temp sealant is a good idea and not using conduit all the way to the elements eliminates a lot of heat transfer.

Actually several good ideas from everyone. I will probably get to the wiring next week and take a close look at what works best.