A system and method for detecting a gas leak in a generator is provided. The system includes a source of a non-corrosive tracer gas, and a subsystem for introducing the non-corrosive tracer gas into the hydrogen cooled generator. An infrared imaging device is adapted to communicate with a notification device to display an image of at least a portion of the hydrogen cooled generator and the non-corrosive tracer gas. The infrared imaging device includes a cooled detector, and a filter with a spectral response between about 3 μm and about 5 μm. The detector and/or the filter is cooled to between about −80° C. and about −200° C. The gas leak will be indicated on the notification device. The generator may hydrogen cooled, and on-line or on-grid.