Feeding 2 motor circuits off of 1 breaker

[PhaseShift]

We have a 480V 20A breaker that is currently feeding a combination motor starter located in the field (unsure of FLA rating at this point) We need to feed another combination motor starter in the field that will be added. The question is weather we can parallel this second combination motor starter off of the same breaker?

I am under the assumption that is is possible as long a the two seperate circuis off of this breaker have a cable rated at or above the 20A breaker. We will also need to verify that the breaker is large enough to supply the sum of the 2 motor loads plus 25% of the largest motor load. Are these the only two things that need to be taken into consideration?

 

[__dan]

article 430

article 430

article 430

From memory for single motors loads the conductor size is 125 % of FLA but the short circuit protection for a thermal magnetic breaker trip setting is 200% of FLA. This allows for starting current carrying.

I believe you are correct that for group motor loads code only allows the short circuit protection trip setting at the group sum of FLA plus 25% of the largest motor. This means that the motors cannot start simultaneously, because likely the breaker will be too small for the simultaneous sum of locked rotor amps. NEC is not as generous with the breaker starting current allowance as for the single motor load.

I looked at this recently and came up with the same. Staged non simultaneous starting (on delay timers) may be the adder.

 

[PhaseShift]

I should mention that each combination starter in the field will have their own circuit breaker. The breaker that I am referencing in my OP is a thermal breaker and in this case is being used as a feeder breaker.

For the sake of argument, if each combination starter did not have its own breaker then could my breaker in question be used as the short circuit protection for each starter?

 

[cpal]

You might want to read thru this section and ensure your application fits. If not you may need to look at 430.62
430.53 Several Motors or Loads on One Branch Circuit.