Broan bathroom ceiling fan/light/heater unit wiring

Old 02-12-15, 01:56 AM
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Broan bathroom ceiling fan/light/heater unit wiring

Shop Broan 2-Sone 100-CFM White Bathroom Fan with Heater and Light at
Shop Broan Polypropylene Bath Fan Switch at

Helping friend install this bath ceiling unit.
Ran a dedicated 20amp circuit using 12/2 w/g to switch box.
From switch box ran one 12/2 w/g for the heater portion.
From switch box ran one 12/3 w/g for the light and fan portion. (Ran 12/3 instead of 12/2 because he had enough 12/3 but not 12/2)

Wiring at switch box
Incoming hot (12/2 black) to line (brass) screw on switch
Wire nut all neutrals
Silver screw #1 (12/3) red to vent (blue wire on unit)
Silver screw #2 (12/3) black to light (black wire on unit)
Silver screw #3 (12/2 ) black to heater (red wire on unit)

At unit made all connections as above
Neutral wires at unit wired as
12/2 neutral to heater white
12/3 neutral to light/vent white (could have put these together but just kept them separate.)

Installed breaker; energized circuit.

First switch when flipped on worked, vent went on. Then turned it off.
Second switch when flipped on, spark at switch. Not sure exactly where at the switch was a spark, was not looking directly at it. Breaker tripped. Reset breaker
Second switch when flipped on again the light went on, no spark this time.
Third switch when flipped on heater went on.

Checked each switch position again and again by turning each one on and off again but did not trip the breaker this time.

All the connections were tight so doubtful was that.

Any ideas what may have caused this to trip the first time and then not trip again?

Old 02-12-15, 05:59 AM
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Sounds like your wiring is OK. I would check connections at switch terminals, making sure they're tight and no excess insulation stripped. Make sure box is properly stuffed, keeping ground wires away from terminals.

And I'm nitpicking, but I would make the first switch, closest to door, the light switch.
Old 02-12-15, 06:25 AM
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Thanks for the confirmation in my wiring.
Switch was hanging out of box with electrical tape wrapped around it. Until i confirmed everything was working. do that if installing in metal box as in this case. So no hot wires were touching ground wires or grounded metal box. Used 4x4 because number of wires and size of switch with mud ring.
Also this switch is further in the bathroom. There is switch at door for main can lighting in bathroom.

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