High volt in furnace blower compartment

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crtemp

crtemp

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Wa state
Is high voltage wire allowed in the blower motor compartment of an electric furnace? I thought I remembered reading somewhere It wasn't allowed but I don't have a code book on me.
 
NEC more or less doesn't allow circuits in spaces for environmental air unless they are for components within that space, exceptions for spaces above ceilings and under raised floors.

Otherwise within the furnace itself - mostly need to refer to listing requirements more so then NEC. If it isn't for something in that furnace it probably doesn't belong there for certain.

Otherwise the blower motor itself is usually powered by conductors inside the space you question, but it is listed that way.
 
kwired said:
NEC more or less doesn't allow circuits in spaces for environmental air unless they are for components within that space, exceptions for spaces above ceilings and under raised floors.

Otherwise within the furnace itself - mostly need to refer to listing requirements more so then NEC. If it isn't for something in that furnace it probably doesn't belong there for certain.

Otherwise the blower motor itself is usually powered by conductors inside the space you question, but it is listed that way.
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The hvac company blocked off the knock out where the main power would enter the furnace. Now I would have to make my own hole in the blower compartment just to be able to get to the 60 amp disconnect located in the furnace.
 
crtemp said:
The hvac company blocked off the knock out where the main power would enter the furnace. Now I would have to make my own hole in the blower compartment just to be able to get to the 60 amp disconnect located in the furnace.
Click to expand...

That could be a problem if that 60A feed is powering a heating element or a compressor while the only wiring normally in the blower compartment is for the fan only.
Many furnaces I have seen have the main incoming power feed is a separate compartment with its own entry point(s).
If those are inaccessible there is no way you can comply with the manufacturers instructions and the UL listing conditions.
So regardless of the practical safety of your planned route an AHJ would be justified in rejecting it.:(

mobile
 
Can't speak for your AHJ, but if it were my call I would probably allow it to pass through if in a metal raceway, possibly even a metal sheathed cable.
 
GoldDigger said:
That could be a problem if that 60A feed is powering a heating element or a compressor while the only wiring normally in the blower compartment is for the fan only.
Many furnaces I have seen have the main incoming power feed is a separate compartment with its own entry point(s).
If those are inaccessible there is no way you can comply with the manufacturers instructions and the UL listing conditions.
So regardless of the practical safety of your planned route an AHJ would be justified in rejecting it.:(

mobile
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Here is a picture I took before I installed the wire. I forgot to take an "after pic" so I'll just draw what I did. The spot the power is suppose to enter the box was completely blocked by rectangle ductwork. There is also no room on the other side directly across from that hole. The red line is the path my wire took. I drilled holes and used connectors everywhere it passed through metal
 

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What kind of wiring method did you use? I've done what you described a bunch of times. You have to be careful when cutting holes between compartments that are meant to be sealed off from each other. When I have to do it, I usually re-seal with fire caulk or putty. Sometimes if you don't, the furnace won't work right from what I've been told. Also, wiring in that compartment should be essentially plenum rated since it's within the ductwork.

In the example you gave, I probably would have used EMT and fought it in there.
 
Definitely a bad installation by the HVAC guys.
Is there any way you could have come directly into the left side of the lower compartment instead of going through the upper (blower) compartment?

mobile
 
GoldDigger said:
Definitely a bad installation by the HVAC guys.
Is there any way you could have come directly into the left side of the lower compartment instead of going through the upper (blower) compartment?

mobile
Click to expand...

No. If you look at the picture you can see it's completely blocked by other wiring, metal plates and circuit boards.
 
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