Common excavation depths...

[Nb22x]

I'm looking for some suggestions to get a better idea of what's really going on underground.
What are some common depth ranges for different types of work, ex: stump grinding, light pole anchoring, Cable replacement, picket fence install, utility pole install, etc, (A list of all types and common depths of excavations that you know about would be very helpful!)
Thanks.

[ProfessionalLocator]

I'm looking for some suggestions to get a better idea of what's really going on underground.
What are some common depth ranges for different types of work, ex: stump grinding, light pole anchoring, Cable replacement, picket fence install, utility pole install, etc, (A list of all types and common depths of excavations that you know about would be very helpful!)
Thanks.

St5reetlights poles and fence posts need to be set deep enough their own weight does not pull them over, especially when the ground is wet.
That said they should also be set deep enough that frost heave does not push them back out of the ground. Contractors tend to set them at various depths.


Most stump grindings take it down just deep enough that the remaining stump can be covered up to rot out of sight.

Wooden utility poles have to be deep enough so that their heavy weight does not pull them over and this can vary by size of pole. Consider this a deep dig of 4 feet and more.

Cable replacement depends on the type of cable and type of replacement dig being done.

Streetlight cable is usually 12 to 18 inches deep. CATV drops are often just under the sod and mains deeper. Phone lines the same.

Electric services at two to four feet deep. Gas the same.

There are four major methods of digs for cable replacement.

Hand digging which is seldom used for anything except a very short distance, can be any depth.

Power trench digging and this can be any depth.

Pneumatic bore and these are usually 18 to 36 inches.

Hydraulic bores and these can go to any depth. I have seen these go 10' to 15' deep to avoid existing utilities.

That said when marking you must consider any dig being deep enough to hit whatever utility you are marking.

[Goldenboy]

Invisible fences and stump grinding are about the only thing I would only worry about the drops to houses.

Any other dig you just don't know what they are gonna do. Replacing any pole,fence,or pole anchor they are definately going deeper than your typical utility line.

The problem is you just never know what someone else is gonna do. You could have a small CATV upgrade and one company might just barely scratch the ground and lay the tv in there and a different company may bore it in real deep to try to avoid things.

I've seen your "typical" utility line just inches deep to bored in 18 feet deep for no apparant reason.

[Dave72]

Also, dont forget that the 'surface' may have changed too.
We had a comm line normally at about 2ft deep that had a trouble spot. We found the cable at like 8ft deep. Sometime between original bury and then, the township had built up the roadway to eliminate a dip in the road. Similarily, some action may remove the dirt above your line and suddenly its no longer 2ft deep.. its 6" deep.

[The Big-E]

When locating a H.P. Gas line for a road job, I came across a few spots where it dug up to spot it at just 8" under the surface... I guess over the years there was enough erosion or whatever to make it that shallow... scary (it was a 12" steel gas line)

[TheCableVine]

Relying on commonly held beliefs may save you some time on a few locates without any consequences, but when you don't mark a line because you didn't think they would be digging that deep and it gets hit, your outlook on locating changes pretty quickly. I know, I've said that very same thing at one time. "they hit a phone line? They were just repairing a sidewalk, I didn't think they would be digging that deep." Well, they didn't dig that deep. Turns out the phone line wasn't that deep either.

[sprayandpray]

I have seen Cable TV feeders under streets and alleys get cut by the concrete saw removing the old concrete. You never know how deep any utility is unless it's exposed.