"That being said, you should never intentionally rely on a safety feature to cut you out - they exist as a backup in case you screw up" Right, that was my poin

"That being said, you should never intentionally rely on a safety feature to cut you out - they exist as a backup in case you screw up" Right, that was my point. Of course, a user-induced intentional overcurrent situation will cause the breaker to flip. However, to my original point, thoughtlessly relying on a backup safety feature in this case to protect against intentional cases is something that engineers working on the Therac-25 cancer treatment radiation therapy machine did, which ended up killing several people. The software could be set by the user in the UI to enter a bad state where the high power radiation beam was not collimated (it ALWAYS should be diffused in this high power mode). The software was left this way because there was a hardware interlock to protect against this bad state. Then, the hardware interlocks that were thoughtlessly removed in the new hardware release (without changing the software code), causing a lot of people to be unintentionally irradiated with deadly doses -- since the engineers originally relied on the "breaker" being there, and then it was removed and/or did not always function properly. You can look at pilot safety procedures and checks to see how this mentality is properly put into practice. Nothing is taken for granted.