The invention provides a light fixture that includes a light engine, a rugged housing, and an internal power module that is thermally isolated. The light fixture includes several novel heat management features designed to thermally isolate the power supply in order to reduce the risk of failure and thereby increase the reliability of the light fixture. The light engine includes groups of light modules, each having a light emitting diode (LED) and a zener diode. The power module resides within a rear receptacle of the housing and includes a power supply, a box, and a cover that enclose the power supply. The housing also includes an arrangement of external fins that dissipate heat generated by the light engine. During operation, heat is generated by the light modules, namely the LEDs, and then is transferred along a flow path through a main body portion of the housing and the fins for dissipation to ambient without negatively impacting the power supply.