Getting electrocuted

Have you ever experienced an electric shock? I have. many times. I guess being the son of an electrical engineer fed my interest in powered toys and my education led to the same type of career but my first shocking memory is of being put to bed in a spare room while my parents were visiting friends. I was probably four or so and I was mesmerised by the empty socket for the reading lamp above the bed. Naturally I stuck my finger in it and received 240 volts across the tip as I shorted the bayonet mount contacts. This was a shock in all meanings of the word and resulted in a burn.

We’ve all put our tongue across the terminals of a 9V radio battery haven’t we? I made a lot of electronic toys with triacs that bit and capacitors that discharged through me. Then I was employed repairing adding machines and computers with all kinds of high voltages or large currents. I once watched as a colleague used a spanner to loosen a bus bar from a large capacitor bank in a system which had been turned off and disconnected but not discharged. As he shorted between two bars the spanner disappeared literally in a flash right in his hand. Amazing.

Another time I was present when a switchboard I had assisted to wire up was tested with very high currents. It had 3 phase power running through copper bus bars 6mm thick and 10cm wide but we had forgotten to install the plastic insulators between them. As current flowed the electric fields caused the bars to bend and touch. There was another flash and when we opened the cabinet there were no bus bars to be seen but the entire inside surface of the cabinet was copper plated. Impressive.

A shock between one hand on a 240 volt connector and the other hand on a good earth is like being kicked in the chest by a mule. Trust me. A shock through your arm or fingers will cause the muscles to involuntarily contract very quickly. I was once standing in a factory next to a guy who did just this while holding a screwdriver. He unintentionally flung that tool straight up with such force that it was embedded in the roof some 10 metres above.

My favourite occurred while I was adjusting the picture on a video monitor from behind while the young lady at the keyboard provided feedback on height, width, pincushion etc. I touched the high voltage going to the crt which was about 12,000 volts but with no real dangerous current capability. I grunted and pulled my arm out instantly but the real shock came when the girl screamed and leapt to her feet. I don’t know what I thought but I screamed with her and the whole room full of operators screamed with us. Then we all had a great laugh.

Most modern electronics is low voltage and safe but I am sure there is still time for me to stick a finger somewhere I shouldn’t in a washing machine or something. With a name like Sparkes it is almost inevitable.

cheers
Spike

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