What is the recommended number of turns per foot for loop lead-in wires?

The recommended number of turns per foot for loop lead-in wires is typically five. This standard is based on balancing the need for effective electromagnetic induction with practical installation concerns. Having five turns per foot allows for sufficient coupling with the loop detector, which is essential for accurate vehicle detection.

This configuration optimizes the loop's sensitivity while maintaining practicality in terms of installation space and the physical properties of the wire. More turns could lead to increased inductance, which may result in a more complex installation without significant benefits to performance. Conversely, fewer turns may not provide the necessary sensitivity for detecting vehicle presence effectively. Therefore, five turns per foot strikes an ideal balance for most applications in roadway detection systems.