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Letter: Shockingly direct

Published 14 October 1995

From Helmut Zarzycki and Tom Nash

My personal experience does not quite conform to J. A. Terry’s opinion about the relative dangers of DC versus AC (Letters, 16 September).

As a greenhorn engineer, I suffered a stroke from a 110-volt DC line, with the current passing from hand to hand. I felt no pain, but was completely paralysed and could neither break free nor call for help. Fortunately, after a few seconds, someone noticed something strange going on (my unusual silence?) and banged the red knob. Otherwise, I might have been slowly cooked or electrocuted by the failure of some organ (heart? lung?).

In my later career I experienced numerous shocks from 220 to 380-volt AC (50 hertz), but either the jolt itself broke contact or I was able to drop the tool or wire (rather quickly, I may say). There never was anything again like the DC paralysis.

Over 40 years ago, in the course of an informal meeting at Stoke Mandeville Hospital, R. B. Bourdiloon did a rather hair-raising experiment. Using a foot-operated rheostat, he gradually increased the DC passed across his body via his hands dipping into separate salt-water electrodes.

He got to over one amp without ill effect, but mentioned that any interruption at high current would probably have killed him. I do not remember if he produced any evidence supporting this view.

It makes me wonder if there is really any need to “fry” the occupants of the electric chair.

Issue no. 1999 published 14 October 1995

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