Proper attic exhaust fan wiring...

[TheVodkaMan]

Hey guys,

Last year I installed an exhaust fan in the attic with temporary wiring (extension cord wired to the thermostat box) since I wasn't sure if the fan would be my solution, so I just basically ran the extension cord to the nearest receptacle.

Now that I know that I want to leave the fan in there, I need to finalize this project by making the wiring more permanent and up to the code.

I need wiring-wise recommendations to finish this project. The receptacle the fan is connected to is a 20-amp, 1-gang metal box. Do I need MC cable? Do I have to use a conduit? I got some 12/2 cable but as far as I understand, I can't just plug it in the metal box, correct?

 

[wyliesdiesels]

Remove the plastic LT connector on the thermostat box and add an nm clamp. then run 12-2 NM-b aka romex to the junction box and splice it into the conductors in the box.

 

[TheVodkaMan]

Remove the plastic LT connector on the thermostat box and add an nm clamp. then run 12-2 NM-b aka romex to the junction box and splice it into the conductors in the box.

Thanks, frankly that's exactly what I was gonna do but I just wasn't sure if it's OK for the romex to just lay on the floor once connected to the box

 

[Shiftless]

Seems to me the cable should be protected from damage. Laying in the floor is a vulnerable situation.

 

[TheVodkaMan]

Seems to me the cable should be protected from damage. Laying in the floor is a vulnerable situation.

Exactly my thoughts...

 

[RegeSullivan]

It's an attic/utility room why not run it overhead stapled to the rafters?

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[TheVodkaMan]

It's an attic/utility room why not run it overhead stapled to the rafters?

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Well yeah, that's the plan but the outlet is on the floor next to my furnace as you can see on the pic. The question is - if I staple the 12/2 to the rafters, how do I properly connect it to the metal 1-gang outlet that's on the floor? Do I need to use a piece of conduit? Do I use MC cable instead?

 

[RegeSullivan]

I would staple NM-b to the rafters with proper NM-b staples being careful not to drive them in to far. Attach a 1×2 or 2x4 to the rafter where you want it to drop to the floor where you outlet or junction box is and staple the wire to that as well. Install the proper a proper cable clamp or use one in the box if it has one available and make the proper connections using new wirenuts.

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[RegeSullivan]

I would add... it looks like if you run the wire behind the HVAC you could drop to the floor on a rafter then run it under the HVAC. If you can secure the wire to the floor via a few staples, all the better. Also, if you feel you are crowding the handy box buy a double and proper cover. Not worth jamming 12ga wire in a little box especially if you are not experienced with electrical.

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[Max]

If your major concern is the wires, then RegeSullivan’s approach is a good one. However, you’ve got the gas line just sitting there on the floor as well. Another option would be to run the NM-b on the floor along the path of the gas pipe. Stapled to the floor, not looping around the pipe. Then add 2x4s nailed to the floor along the pipe to give some protection from kicking to both the wire and the pipe.

Alternately you can add the 2x4s, and staple the NM-b to the side of the 2x4s.

- Max

 

[TheVodkaMan]

I would staple NM-b to the rafters with proper NM-b staples being careful not to drive them in to far. Attach a 1×2 or 2x4 to the rafter where you want it to drop to the floor where you outlet or junction box is and staple the wire to that as well. Install the proper a proper cable clamp or use one in the box if it has one available and make the proper connections using new wirenuts.

I would add... it looks like if you run the wire behind the HVAC you could drop to the floor on a rafter then run it under the HVAC. If you can secure the wire to the floor via a few staples, all the better. Also, if you feel you are crowding the handy box buy a double and proper cover. Not worth jamming 12ga wire in a little box especially if you are not experienced with electrical.

After reading your replies I went up there to take a look once again and saw a 2x4 that's used to support the water heater's outlet, so I wonder if it's OK for me to run the wire from the other side of the same 2x4 and eventually make its way to the outlet. It will difficult for me to get behind the furnace due to roof slope; there's no space back there for me to manipulate the wire other than just feeding it through somehow but I like the idea of stapling the 12/2 to the rafters all the way across and just drop it behind the furnace and then run it to the outlet.

If your major concern is the wires, then RegeSullivan’s approach is a good one. However, you’ve got the gas line just sitting there on the floor as well. Another option would be to run the NM-b on the floor along the path of the gas pipe. Stapled to the floor, not looping around the pipe. Then add 2x4s nailed to the floor along the pipe to give some protection from kicking to both the wire and the pipe.

Alternately you can add the 2x4s, and staple the NM-b to the side of the 2x4s.

- Max

yessir.. I have a roll of 25' so if that's enough to run it behind the furnace, I will do that if not, I will run the cable next to the pipe to accommodate the length of the wire. That pipe indeed just sits on the floor... Not sure why they couldn't at least clamp it to the plywood