The present invention relates to an LED retrofit lamp (700) adapted for operation with an alternating current. The LED lamp comprises an LED unit (740), a mains current line, first and second switching devices (710, 720) (e.g., first and second relays), and a control unit (730). The control unit (730) detects an ignition voltage on the mains current line. In response to detecting the ignition voltage on the mains current line, the control unit (730) sets the first and second switching devices (710, 720) to a conducting state such that the LED unit (740) is connected to power. By using the first and second switching devices (710, 720), safety of the LED lamp (700) is improved, in particular when installing the lamp (700) into a fixture designed for fluorescent lamps.