Trenching in primary over existing underground line

[ztrain727]

Hey Folks -

I could use some advice on putting in a 4ft trench to run primary to a transformer at my lot corner. I've got a source for a ride on RT45 trencher, nothing too challenging in terms of trees or soil, but the approach to the existing supply box involves going across a gravel drive and over an the existing high voltage line in 3" conduit.

Anyone have any experience trenching up to a water or electric line? I was thinking of power trenching to within a couple feet and then hand digging with a pick axe and shovel as gently as possible to expose the conduit. Was wondering if there are any tricks beyond calling 811 / using an utility service locator?

Cheers,
Zane :drink:

 

[Firemanbuck82]

A private utility location service, in addition to the Coordinated Utility Locating Agency in your area is very cheap insurance against contacting the HV line with the trencher. Pick and shovel sounds like the best and safest means to do the final exposure on that line. BTW, why are you going so deep with the primary? 4 feet seems overkill.

 

[4570Man]

Your plan was the same one I’ve used successfully before. Sometimes in really hard dirt I’d scratch around with my backhoe and the ground guy would shovel out the loose dirt. I only busted one line doing that and it had an unexpected T in it that I caught with the bucket. Honestly I think the backhoe was more controlled than a pick axe and definitely easier on the back.

 

[ztrain727]

Thanks for the info! Sounds like a good plan... I will have a mini ex out there at some point, but most likely just a CTL and a trencher during this phase. I'll suffer through the bit of hand digging...

4ft is what the utility company requires. Have to buy all the materials through them too. I thought it seemed deep too, but frost line is close to 3ft here (sourthern Rockies, 7500ft elevation) so perhaps it's a frost heaving concern. All I know is I don't want to get hit with 14kv so best to play it safe. I guess they figure the same.

Cheers guys! Enjoy your weekends!

 

[EddieWalker]

Riding trenchers have a magical ability to find what is buried in the ground, and you only know about it after its torn apart what's down there.

Damaging anything that is not yours can cost you a fortune!!!! As a contractor, a do it your selfer and the owner of a backhoe and a riding trencher, I would not do this project myself. Some things are much cheaper in the long run to hire out. Just be sure that they have insurance and experience.

On my own land, when looking for a line or tapping into a line, I do all the digging in that area by hand with a shovel. ONLY after I find what I'm looking for, and 1,000 % sure that there is nothing else down there, will I use my equipment.

Honestly, don't do this project yourself.

 

[plowhog]

Eddie makes a good point also for another reason. I've owned two properties where digging was done, and utilities were marked. On both properties the actual location of the utility lines was different from where they were marked. So what you think should be a certainty could be not so much.

 

[Sprinklerman]

Claa for a utility locate , once its done take pictures before you dig . If you cut something and its marked wrong they cant charge you . The pictures are in case you do hit something , I have had the locater add additional marks to try to cover their ***

 

[Tomtint]

Dig Safe is a free service..can't imagine sinking a trencher into the ground anywhere near power or other utility near by without calling them to mark it.. It's foolish to even consider.

 

[Oldoak]

I would never rely on maps. A utility line locater is pretty accurate. Like Sprinklerman said, take pictures.

Still, I would stay about 2' either side of the marked line with any excavating machine. Even then, I would have a ground man (spotter) watching as I got close. A back hoe or trencher chews up plastic conduit like cardboard so you can never be too careful, particularly around electrical lines. Then I would dig the rest by hand and not swing a pick ax with too much force while locating the actual line.

In fact, my wife and I did such a project just three years ago while digging out a footer and drainage line for a retaining wall which crossed over a buried electrical line and a propane gas line. The propane line bothered me more, because it was not encased in conduit.

 

[Lineman North Florida]

Around here it is the law to call 811 before you dig, I would find out if the electric primary was in conduit or if it was direct buried, also most utility company's put warning tape in the ditch usually about 18" to 24" deep, we pothole and spot stuff all the time while digging holes to set poles it's really not that difficult but you must dig by hand slow and gentle.