A necessary part of any test and tag program is to ensure the appliances are test and tagged at regular intervals.
The main factor that will determine the retest interval for an appliance is the environment the appliance is normally exposed to. The more hostile the environment, the more frequently it needs to be retested.
A hostile environment is one in which the appliance is normally subjected to conditions that would result in the expected life span of the appliance to be reduced due to factors such as;
It is not uncommon for appliances to be moved about a workplace and therefore the normal environment it is used in could change significantly. If the appliance is moved to a hostile environment and would normally be used there, then the retest interval for that appliance should be amended to reflect the change of environment.