Largest Motor

[xformer]

For Calculations 220.50 specifies that motors be calculated in accordance with 430.24. If the motor is 240V, does the additional 25% also apply to the Neutral?

 

[steve66]

240 Volt motors don't typically use the neutral. They are usually just wired line to line.

 

[Julius Right]

I think you are referring to 220.14 Other Loads — All Occupancies

(C) Motor Outlets. Loads for motor outlets shall be calculated in accordance with the requirements in 430.22, 430.24, and 440.6.

Art 430.24 is referring only to live conductors and not to neutral.

Usually for three-phase induction motor no need of a neutral. However, for single phase -phase and neutral- the neutral has to be the same as live conductor.

 

[kwired]

For Calculations 220.50 specifies that motors be calculated in accordance with 430.24. If the motor is 240V, does the additional 25% also apply to the Neutral?

What section is the 25% are you asking about a part of?

 

[xformer]

What section is the 25% are you asking about a part of?

220.50 >>430.24(1) since you have multiple motors in the service.

 

[kwired]

220.50 >>430.24(1) since you have multiple motors in the service.

Gotcha.

If only feeding 240 volt loads on 120/240 supply, there is no neutral to calculate. If some motors are connected line to neutral then I would guess you figure 125% of largest of those utilizing the neutral when determining neutral load, at same time can factor in the max unbalancing on said neutral in the process.