When installing a light switch, receptacle, light fixture, etc, do I HAVE to connect the ground wire to the ground (green) screw? Most if all of the times that I've seen other people's work, it's not connected. The ground is connected directly to the box, and since the device is also physically connected to the box, it too, is grounded that way. Is this grounding sufficient? I've always done it this way, but starting to wonder if maybe it's wrong, and I have to ground the box and still connect a wire to that green screw. The only time I do connect is if it's a chained fixture that has a ground wire going to the fixture, as the chain is not really a good ground on it's own.
From reading other posts it seems people do always connect the green screw to ground, but wondering if maybe this is code in US, while in Canada it may not be. From my understanding plastic boxes are more common in the states while rare here unless outside, so in that case you have to connect that screw.
It's something I just kinda realized while reading other posts, maybe I need to go back and fix some of this stuff.
Some switches and outlets are designed to be grounded just by contact with the metal box, they are known as self-grounding devices. They'll have a metal clip thing on the screw holes, ensuring that the mounting screws are solidly contacting the mounting yoke. The typical devices with floppy loose screws and those little square plastic or fiber washers are not self-grounding and need the ground wire connected.
This is NEC, anyway. Dunno if self-grounding devices are legal by the CEC.