Abstract: A luminaire (1) comprises lamp holder (3) and a lamp (2) mountable to the lamp holder (3). The lamp holder (3) has a body (6) with a cylindrical inner surface (8) and protuberances (1) located around the cylindrical inner surface (8). The lamp has a housing (15) with faces (21) and groups of grooves (22a, 22b, 22c) around an outer surface. Each group of grooves (22a, 22b, 22c) is spaced away from a first end of the housing (15) by a different distance. The faces (21) facilitate insertion of the housing (15) into the body (6) at a first orientation by providing space for the protuberances (10) between the housing (15) and the cylindrical inner surface (8). The lamp (2) is rotatable in the lamp holder (3) from a first orientation to a second orientation in which the grooves of one of the groups of grooves (22a, 22b, 22c) accommodate the protuberances (10) to secure the lamp (2) to the lamp holder (3).

Abstract: A luminaire (1) comprises lamp holder (3) and a lamp (2) mountable to the lamp holder (3). The lamp holder (3) has a body (6) with a cylindrical inner surface (8) and protuberances (1) located around the cylindrical inner surface (8). The lamp has a housing (15) with faces (21) and groups of grooves (22a, 22b, 22c) around an outer surface. Each group of grooves (22a, 22b, 22c) is spaced away from a first end of the housing (15) by a different distance. The faces (21) facilitate insertion of the housing (15) into the body (6) at a first orientation by providing space for the protuberances (10) between the housing (15) and the cylindrical inner surface (8). The lamp (2) is rotatable in the lamp holder (3) from a first orientation to a second orientation in which the grooves of one of the groups of grooves (22a, 22b, 22c) accommodate the protuberances (10) to secure the lamp (2) to the lamp holder (3).