Protecting exposed power rails?

[blapcb]

I am designing an equipment that is connected to a few peripherals using connectors. Apart from the RS232 signals, the connectors also pass the power to the peripheral. Some are 5v and some are 12v. I am worried about "hardening" these exposed connections for any eventualities such as:
- If they get connected to ground (i.e. short)
- If they get connected to another voltage
- If they get connected to a signal wire
What would be the best way to protect the unit so that even if this happens, the entire unit does not get spoiled?
Thanks

 

[FvM]

The first requirements is quite common and can be basically achieved by short circuit and overload protected power supply.

Shorting against another voltage can only apply to current limited sources and will possibly need strong overvoltage protection devices, e.g. TVS diodes. A certain overvoltage level must be assumed however. Finally shorting against signal wire requires full protection of the signal in- and outputs. It's not necessarily possible for all kinds of signals.