In an article that appears in the August issue of Cabling Installation & Maintenance magazine, inventor Erkan Gunal describes the often-frustrating experience of trying to identify one end of a conduit while preparing to work at the other end. “How many of us have ever needed a thoroughly validated conduit run prior to fishing a cable through?” he asks in the article. “The following nine methods, tools, and techniques are traditionally used to identify, track and survey new and existing conduits in the field.”
The nine methods are:
- Electromagnetic underground object detectors
- Ultrasonic conduit detectors
- Electrical current-based tracers and detectors
- Use of a fish tape
- Use of a pulling string
- Use of a vacuum machine and air blower
- Shaking the existing cables or wires inside a conduit
- Shouting toward a conduit opening
- Knocking on a conduit with a hard object
He further describes each method, considering the merits and drawbacks of each. Additionally, Gunal says, a survey he recently conducted among electrical and low-voltage contractors showed their preferences for each of these methods. The favorites were as follows.
- Vacuum cleaner and pullstring combination—25%
- Shaking the wires or cables—23%
- Shouting into the conduit—15%
Gunal invented the Conduit Toner and Detector (U.S. Patent No. 8,220,332), and wrote the article as a way to spread awareness of this new detection technology.