Shared Raceway - 24VDC PLC wiring with Pneumatic Poly Tubing

[zmali116]

Hello,

Background on the topic: We have poultry processing equipment from different machine suppliers in an IMP shell wet washdown processing room and all of the OEM supplied PLC and VFD control cabinets are mounted up in the interstitial space directly above the processing equipment. We have control conduits running from various junction boxes on the equipment up to the control cabinets. The interstitial space has a network of low-voltage (24VDC cables) control wire basket and a separate high-voltage (480VAC & 120VAC) wire basket. All motors have a separate conduit drop from the VFD to the motor.

We are adding additional equipment in the processing room that requires control pneumatics and 24VDC plc cable. I want to run both in an existing conduit, but the electrical inspector says we can't mix systems in the same raceway. To me, all the PLC wiring falls under process machine/supervisory wiring and should be allowed to run the pneumatics with the 24VDC control wiring.

Any guidance on this is much appreciated. Thank you.

 

[hbiss]

Unless the 24V is Class 1, I see no problem with it.

-Hal

 

[don_resqcapt19]

The inspector is probably looking at this.

300.8 Installation of Conductors With Other Systems.
Raceways or cable trays containing electrical conductors shall not contain any pipe, tube, or equal for steam, water, air, gas, drainage, or any service other than electrical.

However if the control system is covered by Article 725, then per 725.3, 300.8 does not apply.

 

[zmali116]

My DC power supplies are NEC Class 2 / Limited Power Source (LPS) certified.
All 24VDC cables running down to the production room have a breaker in their respective control cabinet as well.
Ok, thanks for your input and I will kindly ask the local electrical inspector to revisit this.