Most utilities are located using electromagnetic locators. The equipment consists of two components: a transmitter, and receiver used to pick up the signal.
 For electromagnetic locating to work, the transmitter must be able to apply a signal to an insulated, metallic cable or pipe. Examples include; telephone, electrical and CATV lines, tracer wires (often buried with plastic or other non-metallic pipes), gas and water metallic pipes, and finally security, fire or lighting systems.
PULS, Inc. uses only state-of-the-art electromagnetic locators from such manufacturers as Radiodetection, Metrotech and 3M.
Electromagnetic Locating Methods
DIRECT CONNECTION
Direct Connection is the preferred method for locating utility lines electromagnetically. It is the most accurate method that provides the greatest number of options for locating a buried utility line.
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The transmitter is placed next to an access point for the utility line being traced (a utility structure, such as a vault, valve or meter, where contact with the line can be made). A line from the transmitter is connected to the utility, and a second line is connected to an earth ground.
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The transmitter is adjusted for power output and frequency to match the properties of the line being traced, the surrounding soil and other utilities.
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The receiver is set to the same frequency as the transmitter. The signal, which is sent from the transmitter through the utility line, is traced on the surface.
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INDUCTION
Induction is used when there is no surface access to a buried utility line.
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The transmitter is placed on the surface and over the point where the target line is believed to run.
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The line is then traced as with Direct Connection.
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SONDE
A locating sonde is used when there is surface access to a buried pipe but the pipe is non-metallic. The sonde is simply a beacon that radiates a set frequency which can be traced by a receiver. Typical applications include empty conduit and drain or sewer pipes.
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The sonde is pushed or pulled through the pipe and then traced as with Direct Connection.
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