Abstract: An in-grade light fixture has a lamp compartment having an open upper end with a lens cover covering the open upper end. The lens cover may have a joint connection to permit travel from an open configuration to a closed configuration. A junction box is adjacent to the lens cover along an upper portion of the compartment. If a ballast is utilized for proper supply of power to the lamp, a ballast compartment is adjacent an open lower end of the lamp compartment. A hydraulic isolation chamber extends vertically downward from the junction box to the sealed ballast compartment. The hydraulic isolation chamber is filled with a potting material and prevents wicking of moisture into the ballast compartment.