DC power supply unit for supplying 1 or 2 emergency lights in accordance with DIN EN IEC 60598-2-22 for a rated operating time of 1 or 3 hours. The lights can be installed up to 500 m from the POWERBOX 15. Automatic self-test in accordance with DIN EN 62034 as standard, which indicates a light/device fault via an integrated status LED in the event of a device fault or underload on a light circuit. The light circuit can be switched and operated in both permanent and standby mode. The total power of the POWERBOX 15 is 15 W in mains operation (permanent operation) and 12 W in emergency operation with 1 hour or 3 hours of rated operating time. The maximum switch-on power is 300 W for 100 ms.