Phil Allison wrote:
"mike"
Ok, but how did it make it past the "fire hazard" category.

** The design of the transformer prevents any fire or electrocution hazard.


It's surely a source of ignition when you knock it over onto
a pair of scissors on the desk.

** Shorting the secondary winding is one of the tests carried out when
certifying a transformer as "class 2" or double insulated. The unit must not
overheat or burn to the extent that primary and secondary circuits can
become fused.

Most often this is achieved by adding a thermal fuse to the primary circuit
that will open if the winding temp reaches a point that could damage the
insulation used to make the tranny - about 120C in most examples.

Some older designs used fireproof insulation between the primary and
secondary and the winding were contained on separate halves of a plastic
bobbin. Such a tranny could smoke and burn but still not present an
electrocution hazard.


.... Phil


Ok, but what about the spark that happens when you knock it over
while refilling your butane torch? Or when you just cleaned a part
with alcohol. Dumb design!!!
Safety design is a LOT more than just the obvious.
There'd be a lot fewer houses burned to the ground if only engineers
thought more about how their products are used and the hazards
caused by confluence of circumstance.
Did I mention...DUMB DESIGN!!