On Friday, June 30, 2017 at 12:03:59 AM UTC-4, Diesel wrote:

Thu, 22
Jun 2017 13:11:03 GMT in alt.home.repair, wrote:

I've had 24V xformer burn out and it was due to a shorted wire.

It shouldn't have happened the instant the short occured.

Who said that it did? From what I see in this thread, people are
having problems with them burning out, they put a new one in and
it lasts for days or months, then it fails.

If it were me, I'd put an appropriate fuse temporarily on the low
voltage side to find out if it's failing from overload or if it's
just failing because it's Chinese crap.