My mechanic has an old semi-trailer he uses for storage and wants circuit to it for compressor and air line back to shop.Legal/safe to have air line in same tube? Run is about 40'

300.8 Installation of Conductors with Other Systems.

Raceways or cable trays containing electric conductors shall not contain any pipe, tube, or equal for steam, water, air, gas, drainage, or any service other than electrical.

In same tube? How?

A hose and a cable, in a condiut, NO WAY!

A rigid pipe for air, and 1/2' RMC for power in a trench maybe...

I was looking for that when you posted Joe...

It would be easy to snake a 1/2 in nylon tube into the same pipe you ran wires in to run the compressor. Of Course it wouldn't be legal so why not just run 2 pipes, one for air, one for wires.

Air hoses don't last more than a few years if used. If the hose blew in a conduit it could blow something apart like the cover. I seen some shops run compressed air pvc pipe. It works for a bit then it will explode with shrapnel.

The worst I seen is when someone tried to make an air storage tank. It was about 4x2' with 175 psi in a storage room. On day the end blew off. It flatened a tool box, some shelves. The outside sheet metel wall was bowed out. All drywall was cracked and broken. It took out the light bulbs too.

I would only use ridgid for air. Something elce to think about is water colects at the lowest point in air lines. Sometimes they have drains for this.

Tom

Tom brings up a good point. My FD forgot to run "drainage drops" when they installed shoreline air reels for the vehicles. Now we have to bleed the tanks weekly.

I'd run galvanized steel plumbing pipe (AKA RMC) for the air, and a separate conductor raceway.

Copper works well for air lines my shop has been plumbed w/ copper for 11 years under the slab troublefree plus sweat joints are easier than threading steel pipe.

Thanks for the replies-I needed to back up my position with the owner-used 2-2" tubes.

 
There may be trouble even ducttaping the air to the side of a raceway. Reference 300-11(b) Raceways Used as Means of Support.

What about the static buildup with the air flow through plastic conduit?

Pierre

How does the use of flexible cable/hose carriers on elevator cars and other moving machinery square with 300.8 in the NEC? Are these devices not considered either raceways or cable trays?

I ask because I recently installed such a system, and the manufacturer had specific instructions for installing hydraulic lines, air/water hoses, etc., along with power and control wiring. My installation included lots of low voltage instrumentation, several video cables, a 120VAC power circuit, and a 1/4" compressed air line. The system in question is an "Energy Chain" by Igus, Inc.
http://igus.bdol.com/echain/ec_cat1.asp?p=ec_6_48.gif

The NEC almost says, but stays short of saying "Stay out of the Elevator shaft"

I'm sure they have just as strict, if not more so, code issues as we do. And, with an open baffle type design, not so much an issue with other services going together, where it might be more nessesary to have them together. (As a more important safety issue....) Where being in an enclosed pipe would (un-nessarily)....

[This message has been edited by e57 (edited 08-16-2004).]