Jetstream67:
Humidity (pure water) is not a great conductor of electricity and all the short circuit discussions assume they designed an ELT battery system without a Thermal or Overcurrent fuse . .
True but mix in a small amount a lot of things and it does conduct well enough to kill you.
An overcurrent fuse by itself would not prevent the battery from heating a low resistance (not dead short) path.
For operation it has to provide 10W or so, plenty to get a small area very hot.