Over Volt Conditions

The IEC 61643 standards have simulations for:

• Lightning via a 8/20µs pulse test
• Surges via a 10/1000µs pulse test
• Ring Wave tests

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Each test allows performance testing and provides confidence on user protection needs.

The yellow part of the waveform above is the lightning 8/20µs pulse test. An MOV device is appropriate for protection against this type of surge.

The pink part of the waveform above is the lightning 10/1000µs pulse test. This has 50 times more energy than the smaller 8/20µs pulse test. A SASD device is appropriate for protection against this type of surge.

The 10/1000µs pulse test represents a standardised surge experienced more frequently on power lines. This is caused simply when current is interrupted either at the switchyards or locally at the customer site. The break in current causes an inductive kick back, similar to how an ignition coil in a car generates a spark.