Larry,
This subject is certainly worth its own thread.
With my machine thus far, I’ve wired in additional switches so that I’ve now got switches at each end of X & Y axis and the single switch at the top of Z (as discussed here - Installing limit switches (not homing switches)).
The X & Y’s are wired in parallel pairs and connected (as described Connecting Grbl · grbl/grbl Wiki · GitHub)
However I’m still struggling to get them working as is (supposedly) described here Configuring Grbl v0.9 · grbl/grbl Wiki · GitHub.
It appears that my issues are now mostly relating to correctly setting up GRBL to enable both the Homing feature as well as using the same switches as limit switches.I just need to spend a little more time reading and a little less time cutting…
Mind you, your suggestion of simply interrupting the power supply if any switch is tripped is looking easier and easier by the day. Whatever I end up doing, I’m glad I took the time to wire in the additional switches with the option to use them as either NC or NO - it’ll save re-running all the cables again.