Jack socket for temperature can short circuit the 5V arduino power => destroy the regulator

[reivaxy]

When plugging in, if arduino already powered, there can be a short circuit.
Also, tightening one socket screw, one of the contacts moved and came to touch another.

And changing the onboard regulator ain't enough, I've now 1 Mega board that runs only with USB power source, and the other delivers only 3.3V... :(

I may end up using VGA sockets, grouping all sensors, and with spare space for new stuff if needed...