Magnetic Utility Locator Equipment
Millions of miles of utility mains are buried in cities, towns and rural areas. These include cables for electricity, telecommunications, television and fiber optics. There are pipes and tubing for gas, water, storm drains and sewage as well. Inadvertently hitting one of these utilities during excavations will, at minimum, disrupt service and may result in costly damage and delays.
To avoid such calamities, underground utility locator equipment is vital for pinpointing mains before breaking ground. This equipment includes underground cable locators, a pipe locator or a magnetic locator.
Types of Underground Utility Locator Devices
There are four methods for underground utility location:
- Potholing – Water or air breaks up soil, which is then vacuumed out. The pothole is visually inspected for underground cables or tubes.
- Ground-penetrating radar – GPR sends high-frequency radio waves below the surface. Any reflections are analyzed by trained operators. Examination depth and effectiveness are limited.
- Low-frequency radio transmission – A separate transmitter sends signals to a distant receiver via utility cables, tracers or tubes.
- Magnetic – The most common method of utility or marker location is via a magnetic locator. This method detects the magnetic field of steel or iron objects at depths up to 20 feet.
What Is a Magnetic Locator Used For?
An underground utility locator using the magnetic method has multiple detection applications for buried objects:
- Survey markers at a depth to 9 feet
- PK nails at up to 1 foot
- Cast-iron pipe to depths of 10 feet
- Manhole covers to a depth of 10 feet
- Well-casings to depths of 18 feet
- Pipe and cable tracers buried up to 20 feet below the surface
Since magnetic locators cannot detect copper, aluminum or plastic, ferrous markers, trace wires or miniature transmitters may be used alongside utilities to aid their location with this type of location equipment.
How To Use a Magnetic Utility Locator
Magnetic locators use spaced sensors to detect fields generated by ferrous objects below the surface. The equipment employs the differential between sensor readings to alert the operator to the presence of ferrous material. These indications are typically a varying audio tone and/or a graphical display.
The operator then uses a combination of straight and X-shaped sweeping motions to pinpoint location. Operators may also adjust sensor sensitivity or indicators to further aid location.
Tips for Finding the Right Utility Locator Equipment
When shopping for utility locator equipment, there are several features to note:
- Battery operation should be 24 hours or more.
- The best equipment provides several levels of sensor and indicator sensitivity.
- Displays should be adjustable and easy to read.
- More distance between magnetic sensors improves sensitivity.
- Bigger locators offer more sensitivity, but lighter ones are more portable.
- Any locator should operate in temperatures from below zero to at least 140 degrees F.
Vendor features should also be considered:
- Research and compare all magnetic locators offered by a vendor.
- Ensure the vendor is authorized by the equipment manufacturer.
- The vendor or manufacturer should offer a strong, several-year warranty.
- Ask for a free on-site demonstration to ensure the locator matches your needs.
- Ask the vendor about accessories and repair services it offers.
Should You Buy or Rent a Magnetic Utility Locator?
When you buy a new underground wire locator or magnetic locator, you have control over its operation and maintenance. If you plan on using such equipment regularly, then buying is the most cost-effective approach.
Renting locators has an advantage when you use such equipment infrequently or wish to test different locator models for particular sites. Fortunately, Superior Instrument also runs a
rental business so that you can get specific locator equipment for your job or try out equipment before you buy.
Utility Locator Resources
How Do Pipe & Magnetic Locators Work?
A magnetic locator detects ferrous materials only, while pipe and cable locators use electromagnetic signal transmitters and receivers to locate underground utilities.
Superior Instrument’s Magnetic Utility Locator Guide
Magnetic underground utility locators come in a variety of sizes with a variety of features to suit your particular needs and budget. Superior Instrument talks through the best locator for each situation.