An older home with metal boxes that don't have threaded grounding holes has both top & bottom cable clamps utilized. The grounds are twisted together, cut very short and are not connected to the box. I may be able to use crimp sleeves to install a ground pigtail. If I connect the pigtail to a self-grounding receptacle, will the grounded receptacle effectively ground the box, or does the concept of self-grounding receptacles only work the reverse way (grounded boxes don't require pigtail)?
In an application where there's no threaded hole for the ground screw or it's impractical to use the hole, I use ground clips.(Don't particularly like them, tho) I don't have the book here, but I think the ground to the box can't be dependent on the device. (said w/ my Crawfish net in hand and ready for action)