What can be run in the same conduit?

Old 05-14-09, 08:43 PM
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What can be run in the same conduit?

I've seen that there are restrictions regarding running low voltage and high voltage wires in the same conduit, but what about this?

I've got a ten foot PVC conduit run (1.5" diameter) between my shop and well pump house that has two 120vac circuits (lights, misc.) and one 220vac circuit (water well pump) in it. Can I run "no voltage" wires in the same conduit? The "no voltage" wires are on the output side of relays (12vdc input) in the pump house that are used as sensors. In other words, the output side of each relay goes to a sensor/logger instead of powering some other device. I was thinking about using Cat5e cable for the "no voltage" wires since I need several pair and I have quite a bit of it laying around.

Old 05-14-09, 10:02 PM
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What you have in place now may be a code violation as code restricts outbuildings to only one circuit in most cases.

The issue with running low and high voltage in the same conduit is really just one of wire insulation. You are free to run low and high voltage in the same conduit as long as all of the wires have an insulation rating matching the highest voltage found in the conduit. That means that cat5 would be unacceptable because of its low voltage rating, but you could use THHN for the relays (assuming that these extra circuits to the outbuilding meet one of the listed exceptions for multiple circuits).

There is also the issue of cross talk and interference which makes running most low voltage signals like phone lines and computer data cables through power conduit impractical as well. Your relays would not be affected by this.

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