Arc Fault requirements in Ohio

[don_resqcapt19]

That would mean the promoters of AFCI are just as much of a snake oil salesman as those that sell the little black box power savers:happyyes:

That was kind of my point with the comment.

 

[GoldDigger]

How small does any gap need to be to stop calling it an arc and start calling it a high resistance connection?

That seems pretty clear cut. If it is a gas-tight connection, there cannot be an arc although there may be a high resistance if the contact area is small enough. But enough pressure for gas-tight would deform the copper enough to provide some area.
If it is a metal-to-metal connection which will carry current at low voltage, then it is a high resistance connection. If the current flow does not start until you go above a voltage threshold, then it is an arc. Or a diode. You can make a very low voltage copper-oxide rectifier from a wire and another piece of metal if you try hard enough.