latest nec on yoke grounding clips?
For decades, the two 6-32 screws tying a device to a metal j-box was considered adequate Equipment Ground Bonding for that device (and if the device was a receptacle, by extension, anything plugged into that device).
Sometime later, it was deemed that a small brass clip must be affixed to at least one end of the device yoke, the clip wrapping around both sides of the yoke strap, and the 6-32 screw passing through both sides of clip, securing it in place, with the screw head bearing down on the outer side of the brass clip. Given setbacks, plaster interference, etc., it was probably rare that the backside of these clips ever contacted any useful metal, with any useful level of bearing force.
It seems to me that the weakness of both these earlier schemes is that they rely on the 2 to 4 screws securing the mud-ring (or exposed-work cover) to transfer the ground-fault amperage to the larger metal conduit system... and apparently some combo of real world post-mortems and engineering analysis in the lab eventually reached this conclusion...?
ANYWAY, I still find higher quality receps that come with a one-sided version of these clips, crimped/riveted to the outer surface of one of the two yoke straps, and the retail packaging claims this makes the device "self-grounding"... which implies NEC compliance...?
OTOH, while I can still find GND clips that fit over the edge of a j-box, the smaller ones which fit on device yokes seem to have faded from the scene, even at hardcore elec wholesalers... or am I just shopping at the wrong places?
What say ye, RKIs?