A clamping force sensor assembly for a transformer includes at least one sensor disposed within a casing. The design and configuration of the sensor assembly is such that it accurately measures clamping force values placed on the windings, without adversely impacting the operation of the transformer and with the ability to continue operating under electrical and thermal changes within the transformer. The sensor assembly can include loading members that distribute the pressure evenly over the casing that contains the sensor. The output of the sensor can indicate to an operator the extent of pressure changes experienced by the transformer windings. The output can be coupled with a process by which the damage to or the possibility of failure of the transformer is readily evaluated.