smoothops10
Member
- Location
- FL
- Occupation
- EE
Wanted to get some opinions on routing of motor branch circuit conductors with functionally associated control conductors. The scenario is a 480V MCC with multiple NEMA size 1 and size 2 starters. The starters provide OL protection, however each of the motors will also be supplied with a winding thermal switch as an additional level of protection. Each MCC compartment includes an integral CPT which will route 120VAC through the thermal switch to a relay coil which interlocks with the starter circuit. The CPT power will be removed with the respective MCC compartment disconnect.
The question is regarding how to route the control circuit conductors to the motor. Option 1 - run a dedicated conduit for the control conductors. Disadvantage would obviously be cost would go up with the dedicated control ckt conduit to each motor. Option 2 - route the control conductors in the same conduit as the motor branch circuit conductors. Potential issues with 2 are whether or not the local disconnect switch would have the required aux gutter space for the control circuit conductors, and per a southwire installation guide 'pulling different conductor sizes at the same time is not recommended if the conductor size or other characteristics are significantly different'. Not sure what the recommended limit here would be, would pulling #6 with #14 control conductors raise the potential for insulation damage while pulling? What would be your approach?
The question is regarding how to route the control circuit conductors to the motor. Option 1 - run a dedicated conduit for the control conductors. Disadvantage would obviously be cost would go up with the dedicated control ckt conduit to each motor. Option 2 - route the control conductors in the same conduit as the motor branch circuit conductors. Potential issues with 2 are whether or not the local disconnect switch would have the required aux gutter space for the control circuit conductors, and per a southwire installation guide 'pulling different conductor sizes at the same time is not recommended if the conductor size or other characteristics are significantly different'. Not sure what the recommended limit here would be, would pulling #6 with #14 control conductors raise the potential for insulation damage while pulling? What would be your approach?
