Abstract: A thermal protection device for a dual input voltage lighting fixture apparatus which includes a reversible connector for coupling either of two possible input voltages to the appropriate terminal of a winding of a transformer/ballast apparatus via a normally closed contact of a heat responsive thermal switch having a heating element electrically coupled to the reversible connector and thermally coupled to the closed contact. The latter contact opens in response to a level of heat above a given value. The transformer winding has two connection terminals, one of which is a tap point, connected to the reversible connector. The connection scheme provides the same energizing voltage to the heating element for each of the two different possible levels of the input voltage. The apparatus will automatically indicate if the connector is reverse connected for either of the two input voltages.