How to Protect Polar Capacitors from Reverse Polarity Supplied Voltage | Creative World 

Very clear. I think this is called crowbar protection. I used to use one diode in series with the power source until I got tired all the support calls, "its not working at all". They hooked the source backwards. So I just added a full wave bridge rectifier to the design. Now with one standard part usually cheap doesn't matter how the power is hooked up. In my limited experience, the ones sensitive to the polarity have more farads per a given size. Over voltage will make them blow also.