Conduits for power and low voltage in same trench?

[75gmck25]

I will be trenching and installing conduit for a detached garage subpanel, and I would also like to run Cat 6 and coax to the garage. Can I dig one trench and lay in one conduit for power and one for low voltage wiring, or is there any kind of separation required (or recommended) between the two conduits?

Thanks,

Bruce

 

[wyliesdiesels]

No separation required, just dont put low voltage and line voltage wires in the same conduit...

 

[naturalgas]

Put in a few conduits. Even if you don't use them right away now is the time. I ran one for power, three for low voltage and one for water. I have two open for whatever in future.



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[Eriehunter]

I like to separate conduits in a trench by a few inches.

 

[Jess]

In my area, power and tel/cable conduits usually go in the same 12" trench, one each side. Put in an extra pull string in the tel/cable conduit for future use. By having a foot between the ducts, you eliminate the induction from the AC power feed. If you want to run low voltage power, I'd install an extra conduit for that use.

 

[PhysicsDude]

Low voltage conduits have less requirements than electrical (shallower depth required, etc) but nothing saying they have to be separated. It's typical to see high voltage and low voltage conduits right next to each other.

 

[larry4406]

Not trench related, but the low voltage techs that wire our houses always try to stay at least 1' away from line voltage wiring and if they have to, try to cross line voltage wiring at near 90 degrees. It was explained to me that they do this to prevent interference and noise issues. Similar to Jess's Post 5.

I will be doing similar this summer for a shed/single car detached garage in Virginia. My plan is to rent a ditch witch, put water line at bottom (36" down), fill 12" for 2" electric conduit (24" down), fill 12" for 1.5" low voltage conduits (12" down), backfill the remainder and grade out the lot.

 

[75gmck25]

Thanks for all the info.

I'll separate the two conduits by at least 12 inches in the trench, and the recommendation to run at least one extra conduit is a great idea. I don't really know what I'll do with the low voltage wiring, other than probably a wired network drop, but new devices seem to come along every few months.

I've seen recommendations to use MHF wire, but quite few folks also use individual wires in conduit. If I just go the MHF route and run 2-2-2-4 MHF, how large would the conduit have to be to make it easy to pull for about 50-60 feet?

Bruce

 

[alfredeneuman]

Low voltage conduits have less requirements than electrical (shallower depth required, etc)

The exceptions to the required burial depth (NEC 300.5) requirements are only those for irrigation controls and lighting systems under 30 volts. Otherwise, they're the same as any other conduit.