When designing a bus bar, one must not forget to consider the issue of testing requirements. This can include initial qualification testing as well as production testing. Both environmental and electrical testing requirements need to be considered and specified, if not on the finished product print at least in a separate document that is referred to in the finished product print.

When considering initial qualification testing, it is a good idea to use Mil-Std-202 and Mil-Std-810 as guidelines for specifying test procedures for bus bars. Specified tests and condition levels should be carefully chosen in order to best qualify the bus bar for its intended application. Initial qualification testing can be quite expensive and can often take many months to perform, depending on the level and degree of testing. therefore, one must be prudent in developing a qualification plan, being careful not to over-specify.

When considering production testing, the most commonly performed test is the dielectric voltage-withstand test (hi-pot test). This basically consists of applying a voltage potential across conductors not in common for a specific time period while sensing the leakage current that results through the dielectric separating the conductors. It is not unusual to test 100% of the manufactured bus bars for hi-pot. This test can be performed under DC (direct current) or AC (alternating current) conditions. The choice depends on the application and the decision is left up to the bus bar designer. The test voltage is uaually chosen to be much higher than the specified continuous operating voltage that the bus bar will endure in operation. A common test voltage and test time for a DC hi-pot test is two times the continuous operating voltage for one minute. However, many designers will specify a minimum test voltage of 500Vdc for one minute, even if the continuous operating voltage is less than 250Vdc. In some cases, the test time can be shortened with an increase in the test voltage.

Another test, not so often specified or well known, is the partial discharge test. This test, generally performed on high voltage AC bus bars, is designed to detect localized ionization discharges across small insulation voids. If the voltage continuously rises and fall, such as with AC, the discharges occur over and over. The discharge energy can create micro damage to the insulation material, which can lead to the generation of discharge paths (treeing) and eventual catastrophic failure. Therefore, it is becoming more common, to see high voltage AC bus bars specified with a 100% partial discharge production test requirement.