A potted transformer assembly comprises a housing portion to form an exterior transformer housing, a transformer unit dimensioned to fit within the housing portion, the housing portion including a first passage to receive the transformer unit in an operative position therein, the housing portion having an inner surface which is oriented to provide an interior cavity between the transformer unit and the inner surface, the interior cavity being dimensioned to receive a predetermined quantity of a potting compound, the housing portion further including a second passage in fluid communication with the interior cavity, the second passage being dimensioned to receive a portion of the potting compound therein, the second passage being located on the housing portion in such a manner that, following a transformer encapsulation step, the presence of potting compound in the second passage is indicative of the transformer being substantially encapsulated by the potting compound.