Spark gap

You need about 25000 volts per inch for a spark in air, so so 230V - as is used for everything here in Australia, and for clothes dryers and such in the USA - can only jump maybe a quarter of a millimetre, on a good day.

So this, despite its appearance, probably did work, for suitably small values of "work".

UPDATE: That URL's dead now. The image is on this page, though, titled "Dryer wire".

(It's from This Old House's Home Inspection Nightmares II; there is, of course, also a I. If that's not enough for you, then I highly recommend the US Naval Safety Center's Photo of the Week, which has extensive archives.)

4 Responses to “Spark gap”

  1. Itsacon Says:

    Reminds me of the place I once visited, where a bloke thought a good way to attach electrical wire to the wall, was to simple nail it there. Straight through the cable...

    Interesting day, that was...

  2. twoflower Says:

    I also highly recommend the "Wall of Shame" forum at HVAC-Talk, where HVAC professionals post pictures of the HVAC (and supporting plumbing and electrical) disasters they encounter from DIYers and other amateurs:

  3. Daniel Rutter Says:

    The Navy site's the place to go for glamour - nothing beats 60 ton vehicles parked on top of each other - but that HVAC board definitely has its moments.

    I particularly like this simple service job. It never occurred to me before that signs might need their own climate control.

  4. Erik T Says:

    Well that blew a few hours that I should have spent studying for finals. Poor timing...

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