William Sommerwerck wrote:

Can you have the double-insulated symbol on
a product with exposed 20V AC conductors?

Because humans aren't likely to be electrocuted by 20V, AC or DC.

But this does raise a question... What about insulation between the primary
and secondary windings? Its failure could put line voltage on the secondary.


There are high isolation transformers with the windings on separate
bobbins. The efficiency is lower than traditional overlaid winding, but
the two windings aren't close enough for anything less than a lightning
strike from reaching the secondary and there isn't any design that is
safe from a direct strike.


--
For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!