Running power and controls cable in RMC

[vasiqshair]

Can I run power and controls cable in the same metal conduit if the controls cable is shielded? I am running a total of 750' of controls and power cables, so installing one conduit, instead of two, can save cost. The total footage is not one long straight run; it comprises 25 runs of 30'. The controls cable is 8-pair #18 twisted pair carrying 4-20mA signals. The power cable is #12 carrying no more than 5A at 120VAC. Doesn't the shield serve the same purpose as conduit and will prevent interference of signals from the 120V power cable? Location SC, USA.

 

[petersonra]

Likely the 4-20 mA signals are class 2 circuits. that should tell you the answer to your question.

you might be able to put both of them in the same conduit if you put one of the cables in RNC. I think there is a product made specifically for this purpose though I can't think of what it is called off hand.

 

[tom baker]

Class 1 ckts can be run with power if functionally related. Class 1 circuits are wired with a chapter 3 wiring method, examples could be motor control ckts
To answer your question, we need to know what the controls do, connected to, or controlled from, and voltage, but as pointed out it likely class 2
shielding and induced noise is not a code concern. Issue is if the insulation fails, melts, and power is shorted onto the controls, the control equipment is not designed for voltage, it can cause fire/shock.
Class 1,2,3 are in the scope of Art 725

 

[hbiss]

Can I run power and controls cable in the same metal conduit if the controls cable is shielded?

No.

-Hal

 

[LarryFine]

In most cases, data over UTP is immune to 60 Hz interference.

 

[vasiqshair]

@tom baker
we need to know what the controls do, connected to, or controlled from, and voltage,
The control cable runs between a gas measurement device and a PLC; bunch of 4-20mA signals that tell the control system the concentration of gas, process temperature, etc.