Utility locating school: equipment and technique
Successful utility locating requires good equipment and better technique. When problems arise, fault most often lies with the person, not the equipment.
It’s easy to mistake a job site problem for an equipment malfunction. Bad depth. Doesn’t locate right. Those are the types of brief, vague descriptions that sometimes accompany McLaughlin locators that get sent in for repair, says Matt Manning, the company’s products manager of electronics.
“We have a physical test we do where we check the equipment at three points. We check multiple frequencies and different modes of locating. If we can’t find a problem, we can’t fix it,” Manning says. “An extremely high percentage of the units we send back out, we never hear about again, which indicates there must have been something wrong at the job site. That’s not our goal. We don’t like sending people equipment where we didn’t define what was wrong. But a majority of the time it’s the user not understanding the job site.”
Effective locating begins with identifying potential issues and using the equipment properly.
“Sometimes a locator is only as accurate as its operator,” Manning says. “There can be a lot of human error. A locator is designed to be held straight up and down, not swinging around.
And you don’t want to grip the instrument. You want to keep your thumbs relaxed so the locator is always hanging down.”
That allows the locator to move along a consistent, horizontal plane — not according to the contours of the ground.
“I’ve seen a lot of bad locates on the inclines and declines along the side of a road because the instrument was not being used on a consistent, horizontal plane,” Manning says. “I saw a case where there was a mislocate on an embankment because the person was just trying to keep the locator at the same distance off the ground and was not moving on a consistent plane. The locate was right — if you were going off an angle.”
From there, accurate locating is about adjusting to the conditions of the job site. For example, say you’re trying to locate an underground line in an area congested with other utilities. Manning suggests locating the line to a known point.
“You don’t want to just walk away 50 feet from where you’re connected, start to locate and say with certainty you have your line. You want to do an evaluation. Locate back to the source and, if possible, the next visible indicator. I’ve seen a lot of bad locates in which the operator walked to where they thought the utility should be and thought they had it, but they didn’t understand that the signal they were sending out wasn’t on just their utility.”
A remedy for improving the likelihood of staying on your targeted utility in a congested environment is to start your locate in a less congested area.
“People tend to focus on the congested environment,” Manning says. “Instead of setting up at, say, a telephone pole or utility box in that area, go to the next one that’s not in the congested area. Locate from the uncongested area into the congested area. That can help a lot in that situation.”
An understanding of soil conditions is also important. Dry soil is less conductive than wet soil and may produce a weak signal on the line being targeted, creating a more challenging locate. That comes into play especially with sandy soils.
“If it recently rained, sand might work alright, but sand drains very quickly so the top surface might not contain any moisture,” Manning says. “You might have to use a different (grounding element). I’ve used a stop sign before to get a ground in sandy situations.”
That can also be helpful in the wintertime when you may be dealing with frozen ground.
“Frozen ground is highly resistant. One time I used a sign that was below the frost line,” Manning says. “That got me from a high resistance down to a wet, low resistance. The key is getting a good ground for the transmitter.”
Develop an understanding of some of these finer points of locating and perhaps you won’t find yourself sending the equipment back to the manufacturer, assuming that it’s the source of your difficulties on a job site.
“People I have worked with who have at least a day of locator training — and I don’t mean on only the instrument — are much better than someone who just grabbed the equipment, read the manual and went out there,” Manning says. “It’s two parts. You have to know the equipment and how to utility locate.”
It’s important to be able to accurately identify the location of underground pipes and cables before getting started on a project, so you need your locator working properly. Here are seven tips aimed at keeping you on target:
Establish a test point. Regularly test your equipment on a known pipe or line, so that if a problem arises in the field you can immediately rule out equipment failure, says McLaughlin electronic products manager Matt Manning. Mark this location and you have a go-to point every time you need to test your equipment.
Check your frequency. To begin, be sure your transmitter and locator are set to the same frequency, says Eric Huber, a senior product manager for RIDGID. “You could be transmitting 8 kHz, but you’re trying to find 33 kHz and you won’t find it because you’re not transmitting it.”
Read the manual. “When people call me with problems, the best questions are from those who have read the manual,” Manning says. “Their questions are usually more specific and I’m better able to help them.”
Take a utility locating course. “Many people out there have been handed down information from the previous guy doing their job. But equipment has progressed and that person’s experience may be related to older pieces of equipment, so some things could get missed,” Manning says.
Keep ’em dry. “Some locators are better than others, but most manufacturers have built their equipment to withstand the elements — snow, rain, mist,” Manning says. “If it’s a downpour where you don’t even want to be out there, it will probably affect the equipment too.”
Don’t be careless. A problem Manning sees far too often is equipment getting run over. “Too many people just lay the equipment down where they’re working or they’ll lean it up against a truck, or lay it on the tailgate. Then someone hops in the truck and leaves; next thing you know the locator falls off the truck or gets run over.”
Remove the batteries. “Dead batteries leak acid. Good batteries don’t,” Manning says. “If you forget to turn off the equipment, you’ll eventually run the batteries down. If you’re using it every day, it may not be a big issue. But if you’re using it, say once a week, that battery will start leaking acid and before you know it, your unit’s damaged.”