before you touch a wire in an appliance how should you make sure itiis not hot

Answer 1

Unplug the appliance.

Answer 2

That will work as long as the device has no stored electrical energy in capacitors. (TV,Computer)
To really be safe, ground the components with a metal tool with an insulated handle to ground (like the metal case)before handling the wires.

Answer 3

Thanks, Damon. That is very useful knowledge that I knew long ago but had forgotten.