Voltage

Breakdown voltage is a characteristic that defines the maximum voltage difference that can be applied before the occurrence of a disruptive discharge between mutually insulated portions of a connector or between insulated portions and ground.

Voltage level at which the connector is tested during qualification test. This value represents the upper physical limit. It is usually set at 75% of breakdown value. Fischer Connectors always applies this ratio to get reliable results even when breakdown values exhibit the large scatter typical in high voltage testing.

Voltage under which the connector will actually work in the equipment over the normal expected lifetime and in typical environmental conditions. This value depends on connector design and specific operating environment as well as on safety requirements.

Generic standard recommended for typical electrical devices. It takes into account long term degradation of insulating materials under variable aggressive environmental influences and uses creepage distance as calculation basis for the operating voltage.

Fischer Connectors recommends the use of IEC 60664 in the general multipole connector specifications, unless other more specific standard or regulations are applicable to the design. For example, IEC 60601 provides adequate special guidelines for medical devices.

For cases where the connector "on-time" or duty cycle is low, and there is little exposure to environmental factors, for example scientific instruments or similar equipment, other previous standards such as BS 9520 can be used. It does not take into consideration either long term environmental effects, or the specific behaviour of different insulator materials and uses test voltage as calculation basis for the operating voltage

BS 9520 recommends to set the operating voltage at

• 0.33 x test voltage for 500V < test voltage < 3kV
• 0.66 x test voltage for test voltage ? 3kV

Similar recommendations are provided in EIA-364-20 (MIL-STD-1344 method 3001 superseded).