Concrete over trenched power water lines?

[Chuck K.]

If city codes allow I plan on running my power and water lines in same 18" wide (width of B/H bucket) ~2.5-3' deep. Its common practice here at the plant to cover power lines with red dyed concrete to identify and protect the lines.

A quick check with a concrete calculator shows me using about 7 yards to obtain 5" layer of concrete for 300' of trench. Cutting a few concrete come alongs down to 16" width and a truck driver willing to work with you it does not seem like a difficult task.



Other than the hassle of dealing with the concrete if you ever had to dig the lines up is this a good idea???

Here is my plan:


Thanks for any feedback. Chuck.

 

[kennyd]

Is the concrete a code requirement? Around here, the EL is just covered with a layer of sand (about 5") before back filling the trench.

 

[bigtiller]

I was on a crew that did this for the city but with telephone lines. They required the line to to be in 6 inch conduit and then covered with 6 inches of sand and 2 to 3 inches of concrete. Then it was back filled and tamped. I think 5 inches of concrete would be over kill.

 

[civesnedfield]

If city codes allow I plan on running my power and water lines in same 18" wide (width of B/H bucket) ~2.5-3' deep. Its common practice here at the plant to cover power lines with red dyed concrete to identify and protect the lines.

A quick check with a concrete calculator shows me using about 7 yards to obtain 5" layer of concrete for 300' of trench. Cutting a few concrete come alongs down to 16" width and a truck driver willing to work with you it does not seem like a difficult task.

View attachment 105696



Other than the hassle of dealing with the concrete if you ever had to dig the lines up is this a good idea???

Here is my plan:
View attachment 105697

Thanks for any feedback. Chuck.

Typically you are required to run the water below the power line. IMHO I wouldn't run both in the same trench. If you have problems with the water you need to disable the power to work on it. As far as concrete over the power only if code requires it.

 

[CurlyDave]

This is a lot of trouble & expense for something you will come to regret doing.

The practices and procedures at an industrial facility are entirely different than those for a residence.

 

[ampsucker]

hardly ever have to dig up electrical lines if correct conductor and conduit is chosen.

water lines different story.

i vote for not co-locating and not doing anything you don't have to for residential service.

some kind of marking tape laid in the trench above the line is a good idea and use the correct color conduit (grey for elec, white for water) is important.

amp

 

[Rowdius]

I've been on alot of government jobs that required the duct bank to have concrete, but that was only high voltage, and even then, it was on 3." If it is low voltage, (under 480v) save your money. If you want to feel better about not cutting into the electric next time you dig, use some flagging tape in the backfill about a foot or so above the wires. (They do make actual trench tape, but flagging will be fine.)

 

[Soundguy]

Don't put concret right on the lines either.. vibrating water lines will rub holes and leak..

soundguy

 

[Charlesaf3]

I wouldn't bother. But I would use conduit and electrical marking tape - the steel kind that the detectors can find.

I wouldn't sweat the water and electrical in the same hole if you are understanding the compromise you are making, and that fixing the water down the road might be a pain. Even so I'd separate the 2 lines as much as possible in the trench - either side would give an 18" separation.

Take pictures of where you put in the trench... you'll find its hard to remember 6 months later. At least for me!

 

[Aguanga]

A lot of good advise here. I work for a general engineering contractor doing underground utilities (sewer, water, storm drain, electric, phone, cable, gas, etc.). As was previously mentioned, unless your building inspector/code is against it you can put them in the same trench; but this could be a problem for future repairs. I'm building my house right now and decided to throw them in the same trench. Do yourself a favor with the pvc waterline and lay the pipe in a serpentine fashion in your trench (back and forth - not perfectly straight) and pour concrete kickers or thrust blocks on the outside of your bends (don't complete encase the fitting in case you need to replace later). The most common problem people have with pvc water lines is not allowing the pipe to have minor room to expand/contract (small amount). Also, a lot of people have leaks occur at bends. Some of the water districts out here require the concrete thrust blocks or kickers at bends instead of restraints (both keep the pipe from shifting around due to water hammering effects) and we found they were worth it on the smaller diameter pvc fittings as well. I wouldn't concrete encase your pipe unless it was very shallow or passing under a creek or other drainage path. If you do decide to encase, make sure you use a low strength (i.e. 1/2 sack mix design) that can easily be removed with your backhoe bucket, but you'd still know it if you hit it. Use a 560-c-3250 or stronger mix for thrust block (quickcrete or similar bags are fine if mixed properly).

View attachment ThrustBlockingInst.pdf