Motors

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wmeek

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Texas
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Electrician
I have an AC job where they are ganging two 4ton air handlers together and was wanting to know if you can supply both motors on single branch circuit. Nameplate on motors is 3/4HP at 4.06A
Is 430.53 (A) saying you can have two or more motors on a single branch ckt. if the motors do not exceed 1hp as long as they don't exceed 6 amps ( is this from table 430.248 or name plate of motor)
 
Dennis Alwon said:
I don't see an issue either with that size motor.
Click to expand...

I do (see an issue) so I must be overlooking something.,. You didn't give a voltage, but your referenced 430.248 and all 3/4 HP motors there are greater than 6 amps.
The way I read 430.6 you would need to use 430.248 vs nameplate therefore
you can't use 430.53(A)
 
Since this is air handlers and there is no hermatic refrigerant compressors in them 440 does not apply, I think the next article to look at is 422, 430 only applies if 422 does not send you there or if the air handler does not have fit in with 422. Most major HVAC manufacturer made air handlers will fall under 422.

The appliance nameplate current is what should be used as well as overcurrent protection if marked on nameplate.

422.10(B) allows more than one load on circuit with an appliance, it sends you to 210.23

I think the main issue with the OP question is if the overcurrent device will allow starting of both motors at same time. Since these motors are typically PSC or more recently ECM motors they probably will not have a very high level of starting current like a capacitor start motor would have. The ECM motors probably will be ramping up instead of drawing much of any surge of starting current.
 
kwired said:
Since this is air handlers and there is no hermatic refrigerant compressors in them 440 does not apply, I think the next article to look at is 422, 430 only applies if 422 does not send you there or if the air handler does not have fit in with 422. Most major HVAC manufacturer made air handlers will fall under 422.

The appliance nameplate current is what should be used as well as overcurrent protection if marked on nameplate.

422.10(B) allows more than one load on circuit with an appliance, it sends you to 210.23

I think the main issue with the OP question is if the overcurrent device will allow starting of both motors at same time. Since these motors are typically PSC or more recently ECM motors they probably will not have a very high level of starting current like a capacitor start motor would have. The ECM motors probably will be ramping up instead of drawing much of any surge of starting current.
Click to expand...


I thought about that but I still think 430 applies
 
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