In the power industry, transients from lightning strikes form the most powerfull transient/surge electrical equipment has to deal with. The Institue of Electrical Engigineers (IEEE) along with the American National Standards Institue (ANSI) developed a standard, dubbed 62.41 as a reasonable simulation for test of a lightning strike on electrical equipment. This test, in essense, is to subject the device under test with 4,000 volts 8/20 uS combination surge with a 10,000 amp capacity directly on its terminal: both differential mode (across the terminals), and also common mode (either terminal to ground). All the while, the unit must be on and operating and suffer no degradation of performance. The Power Tracker(TM) 30 amp unit passed this test as well as the 6,000 V common mode (either terminal to ground - usual lightning strike) requirement. The Power Tracker(TM) user should feel secure some passing transient will not affect their system. If it passes the "direct" lightning strike test, local storms which have been known to fry some regulators won't affect it.