Thermal expansion of materials in High Voltage applications and possible failures coming from incorrect choice

Automotive industry is in the process of changing from conventional propulsion to electric drive. Introduction of high voltage circuits, voltage above 48V, brings new challenges to the design of the vehicle. One of those is the need to protect the harness from harmful ingress of moisture or particulates that would cause is to fail prematurely or cause a hazard for the end user. The usage of various materials for protection against foreign material intrusions can cause unforeseen issues, depending on the choice of materials for encapsulation and the level of protection required, be it over-moulding, potting or enclosure. In this article a case study of incorrect material choice will be presented with possible implications and what to do to avoid the problem from occurring in future endeavours. Incorrect choice of materials for enclosure can cause it to fail in its function due to differences in thermal expansions factors and the possibility can cause the destruction of the assembly.