Conductor sizing and OCPD for combo motor + receptacle load

[Junior_EE]

Feel like this should be easy, but we are struggling to resolve in our office:

We have an existing winch motor system --
1hp, 120v, single-phase, 11.4amps nameplate. Manufacturer requested a 20amp circuit breaker, #12AWG conductors, which is what was installed.

If you have a look at Table 430.248 of NEC, though, code shows a motor like this to be 16FLA. I would expect to run #12AWG conductors with ground-fault and short-circuit protection device of 30amps or max 40amps.

Contractor wants to add a 1amp receptacle load onto the existing 20amp circuit. For the life of us, we cannot figure out how to calculate this. We don't typically combine motor and receptacle loads. Which section of the NEC shows this calculation? Can the 1amp load be added?

 

[Dennis Alwon]

I found this

430.24 Several Motors or a Motor(s) and Other Load(s).
Conductors supplying several motors, or a motor(s) and other
load(s), shall have an ampacity not less than the sum of each of
the following:
(1) 125 percent of the full-load current rating of the highest
rated motor, as determined by 430.6(A)
(2) Sum of the full-load current ratings of all the other
motors in the group, as determined by 430.6(A)
(3) 100 percent of the noncontinuous non-motor load
(4) 125 percent of the continuous non-motor load.

But I also found this

210.23(A)(2) Utilization Equipment Fastened in Place. The total rating
of utilization equipment fastened in place, other than luminaires,
shall not exceed 50 percent of the branch-circuit ampere
rating where lighting units, cord-and-plug-connected utilization
equipment not fastened in place, or both, are also supplied.

Assuming your #12 has 90C insulation and is not part of an nm cable then the ampacity of #12 is 25 amps based on 240.4(D). Now does adding a receptacle change the ampacity rating of the #12? Idk

 

[david luchini]

See also, 430.53(B).

But I think the section 210.23(A)(2) that Dennis pointed out prevents you from adding the additional load (the motor is more than 50% of the circuit rating.)

 

[wwhitney]

But a small panel could be installed to turn the existing branch circuit into a feeder. If the #12 installed is a 75C rated wiring method, then it is good for 25A for Article 430 applications. The 1 HP motor requires a 20A ampacity supply (125% * 16A from Table 430.248), so up to 5A of additional load could be installed. The #12 feeder could be protected at 45A (5A + 250%*20A) (or does 430.63 mean it must be protected at 45A?), and in the panel you'd have a <= 40A breaker for the motor load plus a breaker for the receptacle.

Edit: I'm of the opinion that if 430.63 does not requires 45A protection, then if the feeder is protected at 40A or less, the additional motor OCPD is not required, and the receptacle branch circuit OCPD could be tapped off the combined feeder/branch circuit.

Cheers, Wayne