Selecting Protection Components
Selecting a transient-suppression device for a given application is a complicated procedure that must take into account the following factors:
• The steady-state working voltage, including normal tolerances of the circuit
• The transient energy to which the device is likely to be exposed
• The voltage-clamping characteristics required in the application
• Circuit-protection devices (such as fuses or circuit breakers) present in the system
• The consequences of protection-device failure in a short-circuit mode
• The sensitivity of load equipment to transient disturbances
Most transient-suppression equipment manufacturers offer detailed application handbooks. Consult such reference data whenever planning to use a protection device. The specifications and ratings of suppression components are not necessarily interchangeable from one manufacturer to another. Carefully examine all variables in any planned addition of transient-suppression devices to a piece of equipment or ac power-distribution system. Make allowances for operation of the circuit under all reasonable conditions.