Hi guys. I'm trying to figure out which of these breakers is for the whole-house fan. (Photo attached.) But I'm unfamiliar with the lingo and terms the original electrician would have used in his hand-written labels. Any ideas, before I go trying them each one by one? (I already tried the one labeled W/H, and that's not it.)
F.A.U = Forced Air Unit?
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Well you can rule out the double breakers (those are 220/240v) I would just throw breakers until the fan turns off.
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Man, there are a few head-scratcher abbreviations in there! FAU is a good guess...
If it's not that, where's the sub-panel and what breakers are in it?
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Good catch, I didn't notice the sub panel breaker.
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I particularly like what appears to be a fair number of "dual circuit service" breakers, like kit gfi and fridge on what I would normally call a 220 breaker.
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Well on the one double he has washer and disposal. That is the incorrect amperage for either of those. Makes me wonder what the whole thing looks like inside.
I don't think there is anything wrong with 20A breaker for either of those. It seems they are just using double breaker rather than two solo breakers... Disadvantage would be both tripping instead of one in a fault.
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Thought it said 30
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Nice! FAU was the one. We have two other Forced Air Units in little closets on the 1st and 2nd floors. It appears this panel also has the whole-house fan on the same breaker as the two FAUs. Thanks, Detective @Navat604.
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Mystery solved. The whole-house fan is on the same breaker as the Forced Air Units, labeled F.A.U. Woohoo! One more z-wave switch added. Thanks everyone for the assist. @Navat604 @rlithgow1 @hydro311 @woodsy @timrudd12
Stupid story:
I originally tried wiring this box without turning off the breaker. Lazy bonehead decision, I know. When using my pliers to push the wiring back in, the current arced across my pliers and exploded in a giant mess of sparks and soot. It actually blasted apart the tip of the pliers. That rattled me. So I'm glad you guys helped me turn off the breaker, like a decent man ought to do.
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Correct. That would be your Water Heater.
F.A.U would be your air-handler, probably not the whole house fan.
I would check your sub-panel as others have suggested.
Edit: I was obviously wrong!
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Good try though! That was my initial thought as well. The subpanel is well labeled with a bunch of rooms and stuff, so I was 98% certain it didn't have the whole-house fan on the subpanel. I'm tempted to use my label maker to just put sweet clean perfect labels on the panels, in beautifully legible Arial bold.
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Geez...I'm glad you got lucky and weren't hurt!! Another reminder that the more we hurry up, the more behinder we get... 
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Yes, oh wise one. Thank you for the behinder reminder.
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I see this topic is closed - but in case someone comes looking - I have used 'Toners' to track circuits. The same concept as Toners with network cables.
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