Because they are plastic there is no need to attach a ground wire to it. Dont rely on metal sheathing or an exposed ground wire.
How To Ground Electrical Wires 4 Different Ways Better
How to ground a light switch in a plastic box. The clips do not substitute for fastening the wire to a stud within the code requirements iirc 8. You are not grounding plasticnot all switches have ground screw so how would the metal on the switch be grounded without being attached through the 6 32 to the bonding stripall our plastic and pvc boxes have a green screw attached to a strip which in turn is threaded and joined to one of the mounting holes for the devicesa metal wp. In canada there are or should be ground screws inside the back of nm device boxes. Strip the outer sheating back to with in 18 14 of the entry point. Box that had no bonding strip. Just push the romex through until you have approx.
A modern residential light switchcosts less than 1. Connecting the ground wire to a metal electrical box will energize the box in the event of a short circuit. Plastic boxes usually come with tapped screw holes for easy attachment of switches and outlets. Cover for instance would not be grounded if mounted on a pvc. Since it is made of a non conductive material switches and outlets cannot short out if they touch the side of the box. When you have a ground wire and there is no place to attach it then place a wire connector over the end coil up the ground wire and push it back into the electrical junction box.
The box could overheat and start a fire or someone could get a shock from touching it. If you cant do that or if your box is plastic wrap one turn of the ground wire around one of the screws that secures the switch to the box. 6 through the box. Never cut the ground wire off. The light switches in the loft conversion have plastic back boxes. The usa and canada take different approaches to grounding in non metallic nm.
Plastic or fiberglass device boxes. The clips in the box are retainers for the nm cable. Ground wires and ungrounded fixtures and boxes. There is a metal strap that then bonds the yokes of each device. One of these is a two way gang switch which had a sleeved earth hanging about when i removed the switch so i attached this directly to the earth terminal on the chrome switch. Plastic electrical boxes have their pluses and minuses.
If you cant connect the ground wire to the electrical box instead assuming its a metal electrical box.