based on the nec is it permited to run any other line in same trench for race way. example; water line or telecominication wires.
The NEC is silent on the issue
Since NEC doesn't "disallow" it, it shouldn't be a problem. We use this common trench set-up often with primary power, secondary power, communications, tv, and gas line all in the same common trench. We use a similar common trench detail that are usually in utility company infrastructure installation manuals, there is usually about a 12" separation between systems. As far as water line, there shouldn't be a problem. Metallic water lines are ground bonded in buildings, and all electric lines underground get wet. Unless the water company or civil engineer in their codes have an issue.
I'd have to agree that the NEC is silent on this issue.
However, from a practical standpoint. I could see a potential safety issue down the road in the case of a water line break.
If the water line breaks or is damaged, that means digging down, through the trench and potentially damaging the other utilities in the process.
I would think that if possible, you would want to separate the installations at least in a way that provides protection for the electric and if present the gas line.
Just something to think about.
thanks for your response i could not find anything in the NEC thats why i asked but i think it would be up to an individual opinion. and a safety point of view.
If the wiring is before the outside meter, the utility companies should have the say on those trenches. Usually here in NJ the electric/cable and Telco can all go in one trench. Sewer and water in another trench and gas is usually seperate. If the trench in question is on private property and after the utility meter, the all is fair game in the same trench.
There's only one safety net, let's say, thay gives us some protection. If the Service Conductors are direct burial, they need a warning ribbon 12" above the conductors. I don't have a copy of the NESC but if the NEC is applicable it would be Article 300 section 300.5(D)(3). I suspect the wording is similar in the NESC.
It would be permitted - NEC code wise - to have tel. co and power in same trench...maintaining a 6" clearance(? Article #, anyone..or just a "rule of thumb"?)...BUT water and gas lines usually go DEEPER according to their respective codes and standards. Water is generally below the frost line...don't know about gas.
When in doubt, ask the AHJ.
Don't think NEC has anything on it, but local codes may, and of course the utilities themselves may have some say it too. Heres one for PG&E joint trenching.
http://www.pge.com/docs/pdfs/custom...ice_requirements/joint_trench_config.pdf (See #9 on page 3, I have no idea what that code is?)