Can Microplex run along side AC?

[JustChip]

Hey all,
I'm bran new to this list, but it looks as though it is an amazing collective knowledge base. I need a small drop of that knowledge.
I need to run power to power dimmes from one side of the room to the other. There so happens to be a very accommodating conduit running from almost exactly point a to a little to the left of point b. It does have my control cable (3pin Microplex) running currently. We're talking about 75'.

Is there a problem running AC and microplex along side each other like that? I'm really hoping to use this conduit as there's not really an easy alternative. Let me know what you think.

 

[derekleffew]

... Is there a problem running AC and Microplex along side each other like that? I'm really hoping to use this conduit as there's not really an easy alternative. Let me know what you think.

From a degradation of signal viewpoint, likely not an issue. However, per 2011 NEC 725.136(A), control wiring and power cabling cannot occupy the same conduit.

 

[David Ashton]

The only limitation here is that all
the conductors must be insulated for the maximum voltage that will be present in
the common location. For example, nonpower-limited 6-V circuit conductors running
to a valve motor can run in the same raceway as 277-V circuit wiring to a duct
heater, if both sets of conductors have 600-V (technically 277-V) insulation
?????

 

[derekleffew]

David, we have that here also:

NEC 300.3(C) Conductors of Different Systems.
(1) 600 Volts, Nominal, or Less. Conductors of circuits rated 600 volts, nominal, or less, ac circuits, and dc circuits shall be permitted to occupy the same equipment wiring enclosure, cable, or raceway. All conductors shall have an insulation rating equal to at least the maximum circuit voltage applied to any conductor within the enclosure, cable, or raceway.

but 725.136 prohibits Class 2 circuits in the same conduit as power wiring.

 

[JD]

While it is true that a clean AC circuit running near a DMX or other data (Multiplex) cable should not cause a problem, the real question is, "When was the last time you saw clean AC?" Most AC lines are dirty with noise, some of the worst (of course) being those running from the dimmers to the fixtures.

We all bundle DMX and Soco together running to a truss, and rarely have problems. Still, the truth is, running the lines together should be avoided if possible. (Why invite the Devil in?"

Now, open air and conduit are two very different subjects. See the codes regarding that. The primary reason it is a no-no it that a short or fire in a conduit could put AC in direct contact with the thin data lines. These lines could then produce a shock hazard or initiate a fire elsewhere as the AC finds a path to ground.

In addition, any EMF cross-talk is greatly increased in a metal conduit. (Think of setting a firecracker off in a shower stall!)

 

[TimMiller]

No you cannot run data through the same conduit as power but you can run data on the outside of the conduit.

 

[STEVETERRY]

No you cannot run data through the same conduit as power but you can run data on the outside of the conduit.

Tim and Derek are correct.

ST