Arrangement for injecting plastic into a cavity of an injection mould comprising a platen, a mould plate delimiting the cavity, a molten material distributor, and at least one nozzle having an elongated nozzle body with a nozzle opening, said nozzle body extending through a hollow space shaped in the mould plate from the molten material distributor to the cavity, wherein the liquid molten material fed in through the nozzle is injected into the cavity of the injection mould through the nozzle opening, and wherein at least one electrical heating element (20.1) is arranged on the outer side of the nozzle body, the nozzle body being heatable to a predetermined temperature for the purpose of liquefying the plastic material by means of said heating element, wherein a temperature sensor is arranged in the hollow space of the mould plate between the heating element and the nozzle opening, the temperature-sensitive sensor surface of which temperature sensor is arranged at a distance from the electrical heating element (20.1) and is thermally insulated from the heating element (20.1) on all sides by an air space (d1, d2), and wherein an electronic measurement and evaluation device coupled to the temperature sensor is provided, which is configured, with the heating element being activated, to detect a rise in the temperature measurement values (T meas) detected by the temperature sensor beyond a predefined temperature threshold value (T threshold), and wherein an alarm device coupled to the electronic measurement and evaluation device is provided, which generates an alarm signal if the temperature measurement values (T meas) detected by the temperature sensor exceed the temperature threshold value (T threshold), characterized in that the temperature-sensitive sensor surface is additionally arranged at a second distance from the outer surface of the nozzle body, in such a way that a further air space is arranged between the temperature-sensitive sensor surface and the outer surface of the nozzle body, said further air space thermally insulating the temperature-sensitive sensor surface relative to the outer surface of the nozzle body. a temperature sensor is arranged in the hollow space of the mould plate between the heating element and the nozzle opening, the temperature-sensitive sensor surface of which temperature sensor is arranged at a distance from the electrical heating element (20.1) and is thermally insulated from the heating element (20.1) on all sides by an air space (d1, d2), and wherein an electronic measurement and evaluation device coupled to the temperature sensor is provided, which is configured, with the heating element being activated, to detect a rise in the temperature measurement values (T meas) detected by the temperature sensor beyond a predefined temperature threshold value (T threshold), and wherein an alarm device coupled to the electronic measurement and evaluation device is provided, which generates an alarm signal if the temperature measurement values (T meas) detected by the temperature sensor exceed the temperature threshold value (T threshold), characterized in that the temperature-sensitive sensor surface is additionally arranged at a second distance from the outer surface of the nozzle body, in such a way that a further air space is arranged between the temperature-sensitive sensor surface and the outer surface of the nozzle body, said further air space thermally insulating the temperature-sensitive sensor surface relative to the outer surface of the nozzle body.