Electrical safety of street light systems

Street light systems are publicly accessible electrical pieces of equipment out of the physical control of who operates/owns them. Street lighting systems typically include low-voltage loads, distributed in a large area, and are collectively protected by the same device. Under fault conditions, hazardous potentials may appear on the metal enclosures of these systems, and expose people to shock hazards. To reduce the risk to an acceptable level, different solutions for the bonding and grounding are available. The Standard IEC 60364 and a current worldwide tendency seem to encourage the use of Class II equipment for the street light systems. Class II components, such as the wiring systems, the light fixtures, etc., have double or reinforced insulation. In this paper, these authors analyze technical alternatives to protect against indirect contact in light of the IEC standards. In order to elevate the level of safety offered by Class II metal poles, the adoption of special circuitry and bonding connections to continuously monitor the double insulation of metal poles is proposed. © 2011 IEEE.