Airfield series constant current lighting circuits are inherently dangerous. Much of the danger stems from their unique functionality and design. Airfield lighting circuits are engineered to keep the lights working while aircraft are on critical landing and take-off operations, so they are designed to continue working through serious problems like ground faults and even components on fire. They are extremely resistant to nuisance trips and unexpected shutdowns. Because of this there is no personnel protection integrated into the system such as might be found on parallel wiring systems. This means if a worker becomes energized by an airfield lighting circuit it will not shut down and will continue to run the lights—even if it is through the worker’s body.

Another reason airfield lighting circuits are inherently dangerous is their unique design, which is very different from standard parallel lighting systems used in homes and businesses. It is so unique that unless specifically trained in series constant current theory, most licensed electricians do not understand this system well enough to work on it safely. It is imperative that anyone who works on airfield series constant current lighting systems is properly trained to understand and avoid all electrical hazards involved with maintaining these systems.

AC 150/5340-26C, Maintenance of Airport Visual Aid Facilities, Chapter 2, provides detailed information regarding airfield lighting safety and is a good resource for anyone working with this system.