As a principal engineer at a small automation company that made pharmaceutical testing instruments, I was responsible for assuring regulatory compliance for most aspects of our products, from radio-frequency (RF) emissions to operator safety. Some of the most important items were compliance to EN 61010-1, Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use. For example, one clause in part 12 requires that “No flaming or molten material shall be emitted under normal nor single-fault operation” (but it’s ok if the perils stay inside).
First, of course, I would complete the electromagnetic compatibility tests for radiated and conducted RF emissions and RF and electrostatic discharge susceptibility before the safety tests, which often damage the equipment under test (EUT). The first phase of safety testing was to assure proper grounding, correct power-entry connectors, power-input leakage, exposed hot-spots, and accessibility of lethal voltages by the test finger, among others. But the second, braver phase was the Groundhog Test. First, the EUT was configured for a nasty single-fault failure (of the examiner’s choice), for example, the EUT configured for 120 V but powered by 230 V. Then, the examiner faced away from the EUT, reached behind herself, and, while watching the wall, turned on the power switch. If she saw her shadow, there would be six more weeks of debugging.