This International Standard specifies protective provisions for the operation of lamp systems powered by series circuits in aeronautical ground lighting. The protective provisions described here refer only to secondary supply systems for loads that are electrically separated from the series circuit. This standard specifies the level of SELV, and alternatively PELV, under consideration of additional personnel protection during work on live secondary circuits by electrically skilled persons. This standard also covers the special operational features of aeronautical ground lighting and addresses the level of training and the requirements for maintenance procedures detailed in IEC 61821 and other national or regional regulation. The requirements and tests are intended to set a specification framework for system designers, system installers, users, and maintenance personnel to ensure a safe and economic use of electrical systems in installations for the beaconing of aerodromes. This standard complements existing IEC Aeronautical-Ground- Lighting (AGL) standards and can be used as a design specification.