BCM Community

Fellows,

Is there problem with running 12v wires and 120v wires in the same wire run. I am using THHN stranded wire and wonder about running the two in the same plastic wire tray.

Your thoughts,

Doug

Don't do it

Code does not permit it and there can be problems with other things

Just a tip

Melbo

P.S. Also be sure all the 120 line wires have the neutral run in the same chase

You are not permitted to mix high and low voltage circuits in the same raceway regardless of construction.

Also, "plastic raceway" may not be allowed for 120VAC at all, depending on type.  Non-metallic conduit such as ENT is permitted, and certain listed raceway assemblies are specifically allowed, but most unmarked plastic cable tray is permitted only for low-voltage (below 30 volts) circuits.

Whenever non-metallic conduit and enclosures are used, it is important to pay careful attention to device grounding, and remember to use a ground jumper for any metal enclosures served by non-metallic cable assemblies.

-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)

And looking beyond code requirements, I recall a couple years ago somebody talking about working on a bus where the 12V circuits had been pretty much destroyed when someone did some work on it and inadvertantly made a connection that sent 120VAC into the 12VDC circuits when they reconnected the power.  Did a lot of expensive damage.  So you really want those circuits physically separated so that there is less of a chance that in a moment of confusion or tiredness someone doesn't connect the two.

My electrical boxes are right behind the driver's seat-close to the generator that is also next to the driver's seat like a front engine.  All wiring runs down the lower part of the inside wall.  Since the 120vac is in light weight plastic conduit, the exposed 12vdc color coded circuits cannot be mixed up.  With the light weight plastic conduit, I ran individual ground wires through the conduits also.  Has worked well for over 15 years.  Good Luck, TomC