Lightning surge test

In fact the relevant qualifying test is usually based on keeping the ballast in operation, and simultaneously applying at the input, the well-known 8/20 /is lightning surge test. 

In practice, voltage surges can be of various shapes (Figure 17.2) and may even be so steep as to have a front time as low as 0.2 )as or less. For the purpose of the impulse test, however, only a standard lightning impulse, as defined by 1.2/50 (Section 17.6) can be considered. 

X time taken by the impulse to rise from 0% to 95% of its peak value For the sake of laboratory testing and analytical studies, these surges have been represented by standard impulse waveforms. According to lEC 60060-1 a 1.2/50 /is impulse is called a standard lightning impulse, and a 250/2500 /is impulse a standard switching impulse. 

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