Humidifier wire and breaker size

[james2012]

I am installing an Aprilaire 800 humidifier.

The product allows for a range of input power.
I would like to use the highest setting, which is 240v @ 16amps

I would expect a dedicated circuit of 12 gauge wire on a 20amp breaker to be fine for this 16 amp continuous load, but the installation manual calls for 10 gauge wire and 25amp breaker.

Is it safe to install this to run at 16amps on my 12/20 wire/breaker? Or do i have to run it at the lower setting, of 11amps, as the manual states?

 

[Dennis Alwon]

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[Dennis Alwon]

I am re-opening the thread after discussion with the op.

 

[ActionDave]

I am installing an Aprilaire 800 humidifier.

The product allows for a range of input power.
I would like to use the highest setting, which is 240v @ 16amps

I would expect a dedicated circuit of 12 gauge wire on a 20amp breaker to be fine for this 16 amp continuous load, but the installation manual calls for 10 gauge wire and 25amp breaker.

Is it safe to install this to run at 16amps on my 12/20 wire/breaker? Or do i have to run it at the lower setting, of 11amps, as the manual states?

Do what the manual states. Sure the math works for 16A and 12AWG but there is some reason they picked that size wire and breaker.

 

[JFletcher]

Welcome

I am installing an Aprilaire 800 humidifier.

The product allows for a range of input power.
I would like to use the highest setting, which is 240v @ 16amps

I would expect a dedicated circuit of 12 gauge wire on a 20amp breaker to be fine for this 16 amp continuous load, but the installation manual calls for 10 gauge wire and 25amp breaker.

Is it safe to install this to run at 16amps on my 12/20 wire/breaker? Or do i have to run it at the lower setting, of 11amps, as the manual states?

What is the exact wording of the instructions? if it suggests or recommends #10/25A breaker, that's not the same as requires or 'must use'.

I found the instructions:

"With factory settings, the Steam Humidifier draws 11.5 amps +/- 10%. Use a minimum 20 amp dedicated circuit when installing to operate at
11.5 amps. The Steam Humidifier can be set to draw 16.0 amps +/- 10% by repositioning dip switch #1 on the control circuit board (see Figure
13). When set to 16 amps, use a minimum 25 amp dedicated circuit. For both applications, size wire according to local codes."

ftp://ftp.aprilaire.com/Fulfillment/Humidifiers/800-Series-Humidifier-Install-Instructions.pdf

Yeah, you'd have to use a 25 or 30A breaker, and since you cant run #12 to that in this case, you're stuck with #10 as well. 110.3(B).

That +/- 10% if + would put you at 17.6A maximum which is too high a continuous load on a 20A breaker.