Testing Guidelines
Should Connector Shells be Tested?
While plastic shells don't need to be tested, metal shells and even plastic shells with conductive coatings should be included as a test point.
Often failures in testing are attributed to human error. For example, someone connects the wrong wire to the wrong pin. These types of errors can be easy to prevent or repair. But sometimes an error is caused by something you don’t understand and have no control over. Metal Whiskers is this type of error.
Metal whiskers are tiny growths that form on metals. They are electrically conductive and can cause shorts or current leakage. They are so small that they can often grow undetected until they destroy cable and harness assemblies.
It is unclear why they form, but most grow on tin or zinc. Lead can prevent metal whisker growth, but lead, among other hazardous substances, was banned in 2006 by the European Union. Until researchers develop a new method for preventing metal whiskers, cable and harness manufacturers must deal with the problems they cause.
Metal whiskers can cause many problems such as shorts, metal vapor arcs, and contamination. If one of these errors appears for no obvious reason, check for metal whiskers growing on your conductors.
For more information about preventing metal whiskers, read our article in the Cirris Learning Center.
Further Reading:
Copper Cable vs. Copper-Clad Cable