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Hi All,
Hi All,
My humble neighborhood is serviced with underground utilities and every time I need to excavate I am concerned about hitting the “copper roots”. Fortunately, the service drop to my abode was done in accordance with the National Electric Code which specifies the minimum depth at which the power wires are to be buried (four feet for the 22 thousand volt three phase feeder for the neighborhood and two feet for the 220 drop) but the cable and telephone companies ignored the code requirement of 24 inches. These are just under the sod and I have found them with my shovel while planting daisies.
Well, telephone and cable TV lines are not life threatening but it is inconvenient if one is cut.
Here’s how I locate these lines. I must post a disclaimer which is: THIS IS ONLY AN ILLUSTRATION ON HOW TO LOCATE BURIED CABLES. IT HAS NOT BEEN SHOWN TO BE RELIABLE AND IS ONLY OFFERED FOR ENTERTAINMENT. YOU CAN BE IN GREAT PERIL DIGGING NEAR POWER LINES.
Get an old AM pocket radio and tune it off station at the low end of the AM band. As you pass it over the suspected cable burial location just above the soil you will hear a change in noise and perhaps even receive a distant station. With a little practice you can locate the cable within inches. I cannot describe what to listen for but if you try this you will figure it out. The operative principle here is that the underground wire acts as an antenna for RF signals and noise and this is coupled to the loopstick in the AM radio and is dependent on the proximity of the radio to the wire. This is just meant as an idea for you to try but it works for me.
A great enhancement for those so equipped is to use an AM signal generator coupled to the wall outlet line and ground using series capacitors and tone modulated. Much more easily detected but the method mentioned above works well enough for me that I forgo the generator.
Neil
Total posts : 45366That’s an inventive way to locate undergrounds.
In Ohio we have the OUPS statewide service for locating underground utilities. It’s required by law that before you dig you call OUPS and notify them where, when and what you are digging. They in turn notify all utilities in the area. The utilities are supposed to respond and mark the location of their underground facilities. You are supposed to wait 48 hours after notifying OUPS before you dig.
As a traffic signal technician I receive several notices everyday from OUPS and have to check every one. I use an RF locator to locate my underground traffic cables. The transmitter has an inductive coupler that simply clamps over the wire. The receiver has two internal antennas. When the receiver is directly over the underground wire the signal nulls out and that’s where I put my mark.
Total posts : 45366I am also in Ohio and you are correct in what you stated regarding OUPS. But I will add that while they are pretty good and accurate at locating power lines, their performance on locating service drops on private property and CATV trunk lines in the right of way, in my experience, has been abysmal.
I have had them locate telephone lines where they do not exist and totally miss CATV trunk lines. I suppose without really knowing that if you call them and then hit a line they missed you could blame them but I prefer not to do that.
This is why, when digging on my own property, I find the method I detailed useful.
Neil
Total posts : 45366The person that actually marks the underground location doesn’t work for OUPS. OUPS just notifies the utilites and they come out.
Yes, you’re right in your observations regarding how poorly the locator can be. Sometimes, like with my equipment, the RF I’m following will couple to a water or gas main if close to my cables and it may lead me off track but knowing about where I’m supposed to be I can usually ignore those false readings.
The general guideline is hand dig with care within 18″ of either side of the mark they put down. If they don’t mark correctly and you hit their facilities it’s not your fault. But, as you said who wants that hassle.
I’ve been told that, such as with gas lines, they are not responsible for locating lines on private property. Fortunately the person that locates for the gas company here enjoys his work and will do that for the property owner.
Total posts : 45366I really do appreciate your input on this subject but it does differ from what I experienced. Perhaps it is a regional thing. Here, the OUPS guy or gal shows up with some sort of RF wand and red, yellow, orange, and white spray cans of paint and one person locates all the lines. Doesn’t seem to me that each utility is out here based on this observation. I interviewed a couple of these folks and they told me they rely heavily on the plat drawings for their locating. As an example, the CATV trunk under my lawn went bad due to a cut when my water line was installed so they installed via Ditch Witch another trunk several feet from the original. My lawn has been marked many times and every time they mark the dead trunk and miss the live trunk.
Nonetheless, I can understand the problems associated with cable location on private property. Fortunately for me I moved in here when the trenches were still open and I know about where to look.
The difficulties you cited and I have observed in locating underground cables and pipes should serve as a warning to all about digging in areas where underground utilities are located. My cheap and easy way of doing this is just for entertainment and all should realize there are read hazards associated with this. Thanks for your comments since they imply, as do mine, that this is an inexact science.
Neil
Total posts : 45366In Wisconsin we have an organization called Diggers Hotline that locates potential underground hazards. My power and cable TV connect to my house above ground so the only buried services that I’m aware of are telephone lines. I’m curious to know how common buried power supply cables are around the country. Is burying cables the most common approach for providing customers with electric service? It makes a lot of sense to me because whenever we have severe weather here one of the first things to go is the overhead power and cable TV services. Thanks.
Total posts : 45366Our community has its own electric distribution maintained by the city. The majority of our distribution and service drops are overhead however new residential developments are mostly underground as are new retail and commercial sites.
Some of the older undergrounds are prone to failure and the guys would rather see it overhead as it’s much easier and quicker to find and repair problems.
Total posts : 45366Gronsk,
The decision to use underground or overhead utilities mostly lies with the developer of the neighborhood properties. It does incur increased costs but for many the lack of overhead wiring and poles is a plus and is available at a premium in the cost of the property.
I have lived in neighborhoods with underground utilities for the last 35 years and it is nice to have things out of sight. But, on the down side, it is expensive to install and maintain. For example, in an area near me which is 25 years after the initial build, the underground power wires are deteriorating and there is a program ongoing where they dig up the ends of the trunk lines and pump some sort of insulating compound into the lines in the hope of preserving the insulation for years to come.
On the plus side, the lines are away from lightning, but on the minus side they are expensive to maintain. I don’t know about general trends but in the area around here all new housing and commercial developments have underground utilities. In the beautiful downtown area of my modest city they are in the process of taking down the pole lines and putting them underground so I guess it is a trend.
My city, many years ago, began laying concrete vias under the streets with the intent of leasing conduit space for fiber optic cables. This has come to fruition and the city is making a fortune on these leases. For once, city government did something right.
Neil
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