Originally Posted by herk7769
At some point this thread got hijacked to a discussion on battery jumper cables. A permanently mounted properly installed selector switch should not "spark" a gas explosion regardless of which battery cable it is installed in.
And a really good switch would have a hermetic seal to keep
any gas out. No gas, no danger.......
[Even if not totally sealed, the hole(s) to the outside world
might be small enough to allow the internal flame to "cool"
enough that it would not propagate outside the switch.
Wouldn't want to trust MY life to that though......]
The only concern then would be the external exposed connection,
if it was hot, and then some good insulation and regular inspection
would lessen any danger.
At that point, only danger would be damage to the insulation
of a "hot" cable due to vibration, etc. Maybe same problem
as with with aircraft wiring and same solution - secure them
wires and inspect often!
Possibly that's why the switched-ground solution came
about - unwillingness to do regular inspections....??.....
A little more safety margin for Bozo?