Re: Definitions of High Voltage

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Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>

>> As per North's paper (High Voltage Insulation, pg1), any

>> voltage below approximately 340V will not discharge through
>> air, regardless of spacing or barometric pressure 
> what about 120 VAC?

	cf below.

> ever unplug something while its still on?

	Yep.

> Those are the same sparks you get from 12kV...

	They are subtly different.  A voltage that will
	not jump across a gap 'by itself' will cheerfully
	maintain an arc/spark IF THE CURRENT IS FIRST FLOWING.
	Thus, if current is flowing in the 120V circuit
	it will spark a bit if disconnected hot.
	This is especially true of inductive loads.

	True Story:
	I was at NH, Connecticut, waiting for a train.
	NH has electrified service to NYC, at 11 (or is it
	12.5) KV.  One of the cars had a defect, kept
	dropping the pan (contact) to the overhead.  12kv
	will spark over, about half an inch (varying with
	electrode shape, etc, etc....)  But.  AS the pan
	dropped, slowly drawing out the arc, it would stretch
	the arc to 2 feet or so, since the arc was started
	with current flowing.
-- 
	best
	dwp

...the net of a million lies...
	Vernor Vinge
There are Many Web Sites which Say Many Things.
	-me