Friday, February 06, 2009

tracks, pink, swiss

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When I look at the photograph of these tyre tracks, I see a pineapple.

In Mount Pleasant, a woman with a carrying voice says to her companion: " Pink! People don't get married in pink. They get married in white."

On my desk is a Swiss army knife, which I have had for a number of years. Thinking about it just now, I recall how it was nearly instrumental in killing me or alternatively how it saved my life. I was in the process of repairing the electric shears with which I used to prune our hedge. When unscrewing the plug from the cable extension, I forgot to switch off the current. The wires of the cable needed to be stripped of their plastic sheaths, in order to secure them to the plug terminals. Using the smaller of the two conventional blades among the many gadgets on the knife, I proceeded to chip away at the plastic, when I was surprised by a flash, a bang and a burnt smell. I looked down at the knife and saw that a notch about 2mm deep, spreading into a cavity five mm wide had appeared in the blade. The fuse had of course blown. The first thing that I asked myself was why I had not been electrocuted. I do so again now.There appears to be no insulation on the knife, which is, I believe, made entirely of steel. I have never sought to enquire further, but from time to time wonder whether there is something in the design of the knife which saves idiots like me from electrocution? Or whether I was just lucky?


Dave King said...

Yes, I saw the pineapple too - before reading the caption. Actually, it's a better pineapple than a pinapple, like van Gogh's sunflowers are better sunflowers than a sunflower.

Roderick Robinson said...

One thing that frequently saves people from auto-electrocution is that the connection to the power source is dropped. That doesn't seem to have happened in your case. Another is that your shoe soles would have ensured poor conductivity to earth; death would have been far more likely had you been standing up to your ankles in bath water. But the most important factor is that the fuse went. You say "blew" which implies the old sort of fuse in which a length of thin wire is stretched between two terminals. Modern fuse boxes (called consumer units because they don't include fuses as such) are far more sensitive, tripping a switch for something as non-threatening as a failed light bulb. One lesson to be learned: stay out of the garden.

Even so the power of the localised arc at the knife blade is, as you say, impressive. In Singapore I was tuning a butterfly capacitor on top of a transformer. I should have used a fibre screw driver, both to ensure safety (there was a 1200-volt potential difference between the capacitor and a metal can shrouding the transformer) and to reduce the possibility of interference. But fibre screwdrivers tended to crumble and I was impatient. I used a conventional screwdriver which, mercifully, had a plastic handle. There was a flash and the rectangular shaped blade-end turned into a perfect sphere of molten metal. In this case a different lesson: stay away from repairing electronic equipment, something I have observed ever since.

Lucy said...


Unknown said...

It was an old fahioned fuse box. We now have one of the new, more sensitive ones. Thank you, BB, for your explanation.I never thought of it as a "localised arc", which I am sure it must have been, but I enjoy the phrase, as much as I enjoy having survived it.

Clare said...

When I was about seven, I remember my mother calling my brother and me to her. She was comforting our little sister. She said: 'Children, Rosey has done something very silly, which we mustn't forget.'

She showed us the buckled stainless steel table knife which Rosey had used to lever a a plug out of a wall socket. My parents kept the knife and now -- almost 25 years later -- it's used for weeding the paving stones.