My setup is two DC-DC converters (hobby BECs) supplies, one acting as a backup for the other. A relay, powered by the primary BEC will automatically switch to the secondary BEC if the output from the primary one goes dead.
Now, I want to protect both BEC's against overvoltage (in case they fail to short the main 18V power supply to my 5V devices). For this I was planning to use a combo zener and polyfuse (or even a polyzen if I can find a suitable one), but I want one that is non-resettable, i.e. when it blows it blows catastrophically. Can I achieve this by replacing the polyfuse with a normal fuse?