480V motors less than 1/2 HP

[circuitrider]

I admit that I'm looking for a loophole for a very type design, but I have a 400A bus available and I need to know if I can make it code legal. Using Table 430.250 for all of my 480V loads for FLA: 100% of all motors plus 25% largest motor plus 125% of continuous non-motor load equals 402 A. (There are no noncontinuous non-motor loads.)

Several of the motors are anywhere from 1/6 to 1/3 horsepower, but I used 1.1 A since 1/2 hp is the smallest size on the table. Is there anything that will allow me to use smaller FLAs for these smaller motors and therefore not have to split some of these loads to a different bus?

 

[bwat]

Although they are all continuous, are there any that is impossible to run at the same time?

 

[bwat]

There's also this exception under 430.6(A)(1). Any chance you have equipment that applies to this?

Exception No. 3: For a listed motor-operated appliance that is marked
with both motor horsepower and full-load current, the motor full-load
current marked on the nameplate of the appliance shall be used instead
of the horsepower rating on the appliance nameplate to determine the
ampacity or rating of the disconnecting means, the branch-circuit
conductors, the controller, the branch-circuit short-circuit and groundfault
protection, and any separate overload protection.

 

[circuitrider]

Although they are all continuous, are there any that is impossible to run at the same time?

Possibly, but it has not yet been confirmed.

 

[circuitrider]

There's also this exception under 430.6(A)(1). Any chance you have equipment that applies to this?

Unfortunately, no. This is all industrial. I'll have to see if any of the blower motors meet Exception 2 though.

 

[ptonsparky]

I you added two motors twice...

 

[circuitrider]

I you added two motors twice...

"100% of all motors plus 25% largest motor plus 125% of continuous non-motor load"
In other words 100%(All motors) + 25%(Largest motor) + 125%(all other loads)

 

[synchro]

... Several of the motors are anywhere from 1/6 to 1/3 horsepower, but I used 1.1 A since 1/2 hp is the smallest size on the table. Is there anything that will allow me to use smaller FLAs for these smaller motors and therefore not have to split some of these loads to a different bus?

Are there motors below 1/2 HP that will be used in non-continuous duty such that 430.24 Exception No.1 could be applied? If so, you could see if using the percentages of nameplate current in Table 430.22(E) for these motors would get you a lower current than the 1.1A for a 1/2 HP motor..

 

[circuitrider]

Are there motors below 1/2 HP that will be used in non-continuous duty such that 430.24 Exception No.1 could be applied? If so, you could see if using the percentages of nameplate current in Table 430.22(E) for these motors would get you a lower current than the 1.1A for a 1/2 HP motor..

I think I can actually use that, and it's probably the best answer in an industrial context. Thanks, guys!