Exposed wiring inside exhaust fan?

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muddyboots

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Electrician
Got a window mounted indoor exhaust fan with a single gang service switch inside the fan housing. My question is does the wire need to be concealed in conduit inside the fan housing, going to the service switch? There are 1/2" concentric knockouts on each side of the fan housing, which I would ordinarily just flex or pipe into.
If it does need to be concealed, could I knockout a hole big enough to fit 1/2" flex and go strait to single gang switch, without there being a connector on the housing? And would that void the ul listing? Thanks for your time.
 
Welcome to the forum.

No, the hole(s) must be at least bushed. Would a chase nipple or box connetor work?

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OK, yea that was what I was worried about. Only problem would be starting the flex on the inside of the housing. An easy solution in my brain would be regular 1/2 fmc fitting going into concentric knockout, with a 1/2 rmc coupling on the inside (instead of lock ring) with another fmc fitting screwed into the coupling. Would something like that be permitted? And would you agree the wire would have to be concealed inside of the fan housing? As opposed to free air inside the fan to a grommet on the single gang box. Thanks for the reply
 
I don't have an exact measurement on hand at the moment buts it's definitely less than 2ft. Probably about 18inches or so. Thanks for the reply.
 
Then never mind what I posted above.

No. Both ends of your flex must terminate in the correct connectors.

Or use NM or MC.

What is the problem with doing that here?

Is this all concealed within the wall?
 
muddyboots said:
OK, yea that was what I was worried about. Only problem would be starting the flex on the inside of the housing. An easy solution in my brain would be regular 1/2 fmc fitting going into concentric knockout, with a 1/2 rmc coupling on the inside (instead of lock ring) with another fmc fitting screwed into the coupling. Would something like that be permitted? And would you agree the wire would have to be concealed inside of the fan housing? As opposed to free air inside the fan to a grommet on the single gang box. Thanks for the reply
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Can you post a picture of the fan?
 
I can post a picture tomorrow morning, but no it is not concealed. It's in a laboratory with an exhaust fan mounted on a wood backing where the window was originally. You remove the back grill to access the switch. There is ceiling grid about a foot or so above the fan. I was planning to flex from my box above ceiling, through the ceiling tile to the concentric knockout on the side of the housing. Unfortunately the AHJ does not allow NM or MC, under almost any circumstance, among many other annoying restrictions. If I were allowed to use mc, could I even pull that through the flex?
 
OK, I agree I would prefer to use flex, but I don't see a way to keep those conductors concealed on the inside of the fan once connected to the housing. Now that i think about it, I remember seeing a factory installed s/o cord from the service switch box inside the fan to the actual motor. Could I run s/o cord in my flex or would it have to be sleeved in conduit?
 
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