Abstract: In the embodiments described in the specification a metal heat transfer cold plate has two sets of parallel coolant passages extending between opposite end surfaces and non-metallic headers made of electrically insulating material are attached to the opposite ends of the metal plate. One of the headers provides an inlet to one set of coolant passages and an outlet from the other set of coolant passages and the other header provides fluid communication between the two sets of coolant passages. The headers are affixed to the cold plate by adhesive or by a snap-in connection having a sealing gasket between each header and the cold plate and the assembled cold plate and headers are insulatively supported by mounting feet attached to the electrically insulating headers.