So far... it seems that the impedance of the lab bench source drops the voltage
below what will sustain the arc across the short circuit of the breakdown. And
so the waveform looks like a spark gap or lightning. Lots of on and offs in
quick succession. ps. we had to use 'reinforced' fuses in the lab. A little
copper tape end to end suffices.
On the other hand, actually out on the power poles, when one of those lines
arc's over to something like its mate, it seems that the source impedance is
minimal compared to what's available on the lab bench, and some rather large
fusing device is about to let go. Hopefully not on pole you are standing next
too.
So yes, a breakdown is possible and a follow on current will follow, as will
the action of the Safety required devices such as a fuse. And even with the
Safety device defeated, the source impedance limits the entertainment value to
merely spectacular. Small blast shields are advised as are clear exits for
those that are easily panicked.
From: "[email protected]" <[email protected]>
To: [email protected]
Sent: Saturday, December 6, 2014 1:01 PM
Subject: [PSES] dielectric breakdown
Hi Everyone,
Is it possible that a fast breakdown of the dielectric barrier, by a fast
event, like ESD or EFT, in a two wire mains power supply, cause a larger
follow-on current from the AC mains and therefore a safety problem. How about
follow-on current from a simultaneous lightning surge that would not by itself
cause a breakdown? Anyone know of an incident of either type? I could set up an
experiment but don't want to set my lab bench on fire. -:)
Doug
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