The present invention relates to a refractory mounting unit for ceiling mounted or wall mounted electric devices and comprises: a refractory housing (1) having at least one wall and an inner and an outer side; the at least one wall comprising one section (9), in which internal contacts (6) are directed to an inner side of the housing (1), external contacts (7) are directed to an outer side of the housing (1) and a line-through (8) is integrated as part of the at least one wall for electrically interconnecting the internal contacts and external contacts (7), a plug (2) having a side being form-closed to the one section (9) of the at least one wall at the outer side of the housing (1), the side comprising contacts (12) for contacting the external contacts (7) of the housing (1), and a clamp (3) for clamping the plug (2) against the one section of the at least one wall.