In the bygone days, you could hardly find a scope with an intact ground pin--they were often floated on line voltage equipment (up to 460V) using a low capacitance isolation transformer--yes there was known and accepted risk--yes, even I, myself, got a few nasty jolts from violating the basic and well known "one hand rule" as it takes two hands to complete the circuit--unless of course, you are standing on a wet floor--much akin to driving too fast and/or smashing your car without wearing seat belts.
The "one hand rule", of course, did not protect against those nasty little set screws found on every vintage Tektronix oscilloscope control knob where harmonics generated by high power equipment found their way into the ether via stray human body capacitance.
On occasion, the ground pin presents a significant danger when the unexpected completion of a high power fault circuit can actually blow up a scope probe in your hand--potentially as dangerous as electrocution.
One of the guys I worked with told me that in a previous workplace, he had to get approval from the engineering manager before he was allowed to 'float' an oscilloscope. Awkward, but not a bad policy.
Putting things in perspective: While spending a career around this sort of stuff, I never knew of anyone personally that was electrocuted by instrumentation malpractice--on the other hand, I did have numerous acquaintances that were killed in auto accidents--however, a good more people drive cars than float instrumentation.
Yes, there are better tools and methods available to us today--this kind of stuff should be taught in all engineering schools.
The "one hand rule", of course, did not protect against those nasty little set screws found on every vintage Tektronix oscilloscope control knob where harmonics generated by high power equipment found their way into the ether via stray human body capacitance.
On occasion, the ground pin presents a significant danger when the unexpected completion of a high power fault circuit can actually blow up a scope probe in your hand--potentially as dangerous as electrocution.
One of the guys I worked with told me that in a previous workplace, he had to get approval from the engineering manager before he was allowed to 'float' an oscilloscope. Awkward, but not a bad policy.
Putting things in perspective: While spending a career around this sort of stuff, I never knew of anyone personally that was electrocuted by instrumentation malpractice--on the other hand, I did have numerous acquaintances that were killed in auto accidents--however, a good more people drive cars than float instrumentation.
Yes, there are better tools and methods available to us today--this kind of stuff should be taught in all engineering schools.
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