Charlie,
Yes it is a 1/4" spade as you thought.  I have several
in the wiring system, and they are suppose to be high
quality.  Since I added the tyrap in May, and it just
now worked off, it probably did take alot of force.

The cold weather may have played a role as well, since
wire tends to shrink a little with cold, whic would
have made it even more strained.  While I removed the
tyrap, and it has some slack, I'm going to rework the
wire and connector on my next trip down to SC.  I'll
lengthen the wire and install a new connector.

Steve