1.Resistive load could not  exceed 60% of the rated current.

2.Inductive or capacitive load could not exceed 40% of the rated current.

3.Electric machine load could not exceed 20% of the rated current.

4.Proper radiator adapted to the working requirement of solid state relay should be equipped, the allowance should be widened when the load radiating condition is not so good. Short-circuit load is not allowable.

5.Over Current Protection: over current and short circuit are the main reasons for permanent damage of output controllable silicon in the SSR, and using fast fuse and air switch is one of methods for over current protection, fuse is also available for small capacity.

6.Over Voltage Protection: It can adopt parallel voltage-dependent resistance(MOV), the MOV area decides the absorption power, while its thickness decides the protective voltage value, generally, 471/10D voltage-dependent resistance for 220V series SSR, 681/10D voltage-dependent resistance for 380V series SSR, 821/10D voltage-dependent resistance for 480V series SSR.