Moving Utility connections underground

[larrym]

We are moving the utility service entrance to our house from aerial on the Garage to a location on the house via underground. The utilities come in from the street via two poles. Last pole is 80 ft to the new location on the house.

Going underground to improve "curb appeal" on the house. The lines currently run across the front of the house from the pole to the Garage.

The basic question is how much separation between utilities do we need to provide when burying.

I have references for burial from each of the utilities but none of the them say how far offset they should be from each other?

I was looking at installing 2.5 or 3 inch PVC for the power, and separate 1 inch PVC for the phone, and cable.

Do I need to dig two trenches (one for power and one for phone/cable or ??)

 

[oldagpe]

I would call the utilities and ask.

12 inches would be a minimum. This is for interference.

I would dig separate trenches, but some jurisdictions don't require that if the conductors are in conduit. As a practical matter, the next homeowner may get new cable or whatever, and you don't want the signal installer chewing into the power conduit.

You may want to think about pulling cables through 80' of 1" conduit.

There are also the NEC requirements to meet.

 

[larrym]

Thanks, 12 inch is the number I was looking for.

I have tried calling into the power company and obviously am not talking to the right department. The lady very nicely suggested that burying the power cable was a bad idea that it would short out!!!

The cable company took a week to get back to me and say that they would charge me $35 to move the connection. Totally avoiding answering the question of depth of burial or spacing.

AT&T....well I'll just add that story to my memoirs

I install submarine cable systems for a living....who would have thought doing trenching 80 ft would be so hard.

 

[oldagpe]

Another bit of practical advice would be to trench the signal, install the conduit, and bury the trench. Then, open a new trench for the electrical, install the conduit, have a roll of ID tape onsite, call for inspection on your permit.

That way, you can run the trencher one time. Assumes that the inspector has no interest in signals.

 

[steelerfan28655]

I get this question all of the time. Here in North Carolina, USA. We will install our power conduit between two and three feet deep, then backfill at least twelve inches, and put the communications on top. Depending on the load of your home and the size of the knockout in the meter base, a 2" conduit from the pole to the MB is most common. The utility will most likely pull in 2/0 triplex, unless you have a 400 amp service. Our 200 amp meter bases will not accept a 3" conduit.

Happiness is a way of travel, not a destination.

 

[eng7122]

agreed with steelerfan. We would almost always place the communications above the power in the same trench.

 

[HornTootinEE]

If you are talking 120/240 V service line, we typically dig a 3' trench, put electric on the bottom, 6" of fill, telecom next, then another 6" of fill and then the natural gas pipe goes on top of that and backfill and finish up the trench. Sounds like most of the guys here would probably disagree with that approach.

If you are upstream of the meter socket on the utility side, NEC does not necesarily apply. NESC would definitly apply. We usually run 1/0 TPX to a 200A service, if it's short. Get outside of 100' though and you'd probably be better running something larger to compensate for voltage drop and for AC inrush, that sort of thing. Our company has standardized on 1/0 and 4/0 Aluminum Triplex, but as steelerfan says you can go with 2/0 also.