On Thu, 14 Nov 2013 19:39:38 -0600, dpb wrote:

If, as somebody else noted, it didn't trip the breaker the likelihood of
a short other than the element is minute. In 60 yrs in a dry climate
I've never seen a static electricity flash from a dryer vent or even got
a shock so don't say it's not possible but surely sounds far-fetched
hypothesis to me.

This is good to know, since the static electricity idea was the only
one I could come up with that was benign.

I would agree that static electricity isn't likely, so, let's forget
about that.

But, if it's not something benign, then I need to figure out WHAT is
making that spark, and why.

The whole fact that there is no explicit ground is part of what confuses
me.

I'll check to see if the body of the dryer is hot with respect to ground.