Old machine moving soon, need help sizing of conductors and fusing.

[stucker1101]

We have an old machine that has no labeling of any kind. All I know is its been fused at the in the cabinet as 480 3ph at 150 amps. The fuses at the Bus Duct are fused at 200amps. The conductors from the Bus Duct are currently #1. My question to the group is more of a thought first. I believe the conductors are too small. The machine in question needs to be considered a continuous load. My questions are simple.
1. Am I on the right path to say that given all other information I should be using 1/O wire?
2. Am I correct in assuming the wire from the Bus Duct to the Machine disconnecting device would be considered a feeder?
Code articles for reference are appreciated....We are still using NEC 2017
Thanks in advance for any help provided

 

[Dennis Alwon]

If the disconnect at the machine is fused then the wire to the disconnect is a feeder. IMO, this should be considered a branch circuit not a feeder but the definition in the nec is clear.. it is a feeder

 

[infinity]

If this is a supplementary OCPD I would agrue that the circuit is not a feeder. This in an OCPD in addition to the branch circuit protection.

Overcurrent Protective Device, Supplementary. A device intended to provide limited overcurrent protection for specific
applications and utilization equipment such as luminaires and appliances. This limited protection is in addition to the protection provided in the required branch circuit by the branch-circuit overcurrent protective device.

240.10 Supplementary Overcurrent Protection. Where supplementary overcurrent protection is used for luminaires, appliances, and other equipment or for internal circuits and components of equipment, it shall not be used as a substitute for required branch-circuit overcurrent devices or in place of the required branch-circuit protection. Supplementary overcurrent devices shall not be required to be readily accessible.

 

[stucker1101]

So to take the next step If all i have to go by is the size of the main fuse which is 3ph 480 fused at 150amp and the Fusing at the Bus Duct is 200amps, What would you say is the correct conductor size and should the fusing at the Bus duct be any different? Code reference would be greatly appreciated.

 

[Dennis Alwon]

It would depend o whether there is overload protection in the motor or somewhere else in the circuit

 

[petersonra]

So to take the next step If all i have to go by is the size of the main fuse which is 3ph 480 fused at 150amp and the Fusing at the Bus Duct is 200amps, What would you say is the correct conductor size and should the fusing at the Bus duct be any different? Code reference would be greatly appreciated.

The feeder conductor ampacity is determined by 215.2 (A). It is possible that based on the actual load of the machine that #1 is adequate.

The OCPD rating (from the bus) is determined by 430.62 if you have more than one load in the machine. It is quite possible it is also adequate.

You would need to delve in to exactly what is in the machine to determine whether or not it is code legal or not.

Alternately, you could just change out the #1 for conductors with an ampacity of 200 Amps.