My mechanical closet is on the third floor of our townhouse and our breaker panel is on the first. To install a steam humidifier, I’ll have to run a 220 line between two floors or outside, both of which are expensive options.

My AC unit is on the roof immediately above the mech closet. I’m hoping I can use that 220 for my humidifier, but the first few electricians I’ve called have simply said that they don’t think it’ll pass inspection so they don’t want to try.

Any thoughts?

  • One of the pros can give specific, definitive answers. Off the top of my head though, if the AC has a "sized just right" set of wires, then you can't add anything else because that would overload the circuit. If it has capacity to spare then you could (in theory) put in a subpanel in place of the AC connection and then connect both the AC and the humidifier to that subpanel. But I doubt that you will be able to do that. – manassehkatz Jan 5 at 23:58
  • What is the currently installed wire size for the A/C circuit, what is currently fitted for an A/C disconnect, and what size breaker is currently present on the circuit? Can we also have the nameplate ampacity and breaker requirements from the nameplate on the A/C's outdoor unit? Last but not least, how many amps does the humidifier pull? – ThreePhaseEel Jan 6 at 0:35

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