In the drop-down selection for enclosure type you can choose between Open Frame and Adapter (or Lamp Retrofit for LED designs). An open frame environment implies the power supply has some convectional cooling and thus can deliver more power. Choosing the adapter or Lamp Retrofit environments environment does not permit any airflow outside the adapter box and implies a completely sealed enclosure of limited volume. The choice of an adapter environment limits the output power of a certain devices due to the thermal restraints.
Use the Estimated Ambient Temperature input box to input your observed or specified ambient temperature. The program uses this temperature to calculate the lifetime of electrolytic capacitors since their lifetime is strongly influenced by their thermal environment. You can click the calculator icon 
to type a custom value. The box where you change the stacking type is marked with 
. Click the icon to restore the automatically calculated value.
Use the Required Safety Spacing input box to specify the amount of margin used when building a margin wound transformer or a transformer which uses foil windings. The required safety spacing differs depending on the desired agency approval, operating environment (low or high pollution) and working voltages that the supply is exposed to. You can click the calculator icon to type a custom value. The box where you change the stacking type is marked with . Click the icon to restore the automatically calculated value.
The Safety Standard list box displays the default standard that was applied by PI Expert when created a design. You can click the calculator icon to select another standard from the list.