Locating Underground Facilities

Proper identification and marking the location of underground buried facilities prior to excavation is done in order to protect the public from harm and prevent damage to the City of Lawrenceville’s infrastructure.

Finding Underground Cables & Pipes

Underground cables and pipes are not naturally magnetic and electromagnetic locating equipment does not directly detect buried facilities. By applying electric current to utilities, we work to locate them by finding the fields around them. A moving magnetic field radiates from the buried utility and if you find this signal, you find the utility.

Locating Equipment

The locating equipment set consists of a transmitter and a receiver. The transmitter’s job is to apply an electric current to the pipe or cable and the receiver’s job is to detect the magnetic field created by the transmitter. Locate sets operate at more than one frequency and we use different frequencies to overcome different situations. A low-frequency signal is tighter around the cable or pipe; it travels farther but is harder to follow. A higher frequency is easier to find but only goes a short distance and may bleed over to another utility; i.e. water, or phone.

As locating the underground utilities is both an art and science, an individual locate technician will usually prefer and be more comfortable using one particular type of locating equipment over another.