The invention relates to a PSE device (2) to be used in a PoE lighting system (1), wherein the PSE device (2) is adapted to receive input power from a power providing system (7). The PSE device (2) comprises a power detection unit for detecting whether the received input power is primary input power or backup input power, wherein the PSE device (2) is adapted to control the power consumption of lighting units (31, 32) depending on the power detection. This allows for an indication of an emergency situation, in which the backup input power is provided, to the PSE device (2) without necessarily requiring data communication means. Moreover, the power consumption of the lighting units (31, 32) can be more efficiently utilized in case of emergency.