Wall illumination unit

The lighting unit (1) has a base module (4) installed in a commercial device box and has a converter and a control unit. A light-emitting module (20) has a LED lamp (24), a plug connector receptacle (22), an electrical energy store (26) and an activation unit. A plug-in device (6) and receptacle are mechanically and electrically connected with each other so that light-emitting module is mechanically held in connected state. The activation unit is configured so that LED lamp is lit and is energized by energy store during failure of power supply through power line.