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Southeast | This is an all too common situation. Running a motor and especially a series of motors off a circuit breaker is not advisable.
Here is a great website to research motor control data: http://powertips-elec.blogspot.com/2010/11/motor-starting-and-runni...
Working off your nameplate photo, the locked rotor current (inrush) at full voltage will be about 365 amps.
So, here is where things get weird when using only a circuit breaker for motor control. In simplest terms (that I will not try to explain) a common load center circuit breaker has about 30% ride through, with the time being directly proportional to the load beyond breaker rating. So an 80 amp breaker (which would be correct for a MCC) even with 30% ride through would only get you to about 108 amps nominal load. Because of I2T this should get you through the inrush if the load is normal. In other words, the harder the load is to start, the quicker the breaker will trip.
Where people 'cheat' by using a higher rated breaker is by moving this baseline proportion. But by cheating the motor protection is greatly reduced if not completely removed.
A true motor control circuit (fuse/breaker, motor contactor, and overload relay or thermals) will handle the inrush so that the circuit breaker can be sized correctly to handle short circuit protection.
If this is purely a temporary situation and the load at start is not excessively high (somewhat subjective but empirical) I would try to go with a 60 amp breaker but have an 80 amp available if possible. A lot of this can be better determined if you have an amp probe.
You are also right on the edge with wire size based on nameplate, especially if you are running on the high end of motor rating. You NEVER want the wire to be the fusible link and you do not want the wire to be warm/hot all the time because it is more pliable. This is a prime source of reoccurring loose connections. So I would go with 4 AWG. If you run a wire calculator that is what specs out.
How much of your service is this going to consume?
***Edit*** I just check the ABB/Baldor website and it says the locked rotor current is only 254 amps. This would slide everything I just said down one size.
https://www.baldor.com/catalog/UCC10150#tab=%22specs%22
Edited by dvcochran 10/17/2021 09:51
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60 amp breaker big enough
