A power module and method of forming the same. The power module includes an extruded tube with internal and external fins, first and second opposing surfaces defining ends thereof, and an internal slot for housing a power converter. The power module includes a bottom plate having a first depression to receive a first O-ring to provide a first liquid-tight fluid seal at the first opposing surface for an electrically insulting oil encapsulating the power converter. The power module includes a cable interface plate having a second depression to receive a second O-ring to provide a second liquid-type fluid seal at the second opposing surface for the electrically insulting oil encapsulating the power converter. The power module includes an end cap to mate with the cable interface plate and accept a conduit fitting to enable an electrical cable to be routed from within the end cap to an external connection point.