Abstract: A housing (2, 4) for protecting an electrical cable (18) having a sheath and at least one core (20a, 20b) comprises a cell (8) for containing the stripped end of the sheath, an open cylinder (7) containing a sealant and a plunger (6) for forcing the sealant into the cell so as to seal the end of the sheath.

Abstract: A defrost control system detects the variation in flow rate of refrigerant through an evaporator 8 while the flow is regulated to achieve a desired level of superheat at the outlet of the evaporator 8. When the flow rate becomes unstable, defrosting of the evaporator 8 is triggered.

Abstract: A defrost control system comprises a superheat detector for detecting the degree of superheat of refrigerant leaving an evaporator or the presence of liquid in the refrigerant, a temperature sensor for sensing the temperature of a thermal load cooled by the evaporator and an electrically operable expansion valve for controlling the flow of refrigerant through the evaporator, each connected to a control circuit. In normal operation, the control circuit controls the flow of refrigerant to keep the temperature of the thermal load constant. However, if the superheat detector detects that the superheat is too low, the control circuit overrides the normal operation and reduces the flow of refrigerant. If the control circuit determines that the time spent in override condition over a period exceeds a maximum level, defrosting of the evaporator is triggered.