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I’m replacing the light switches and plugs in my new house and noticed that all the light switches so far have the ground wires screwed to the back of the outlet box. Is this good enough that I don’t need a ground wire attached to the switches or do I need to pigtail the switches to these as well?

What is the proper method of this? There’s not a lot of slack coming in from the wires if I need to pigtail them.

As an FYI, the switch below has one for the light and one for the ceiling fan.

outlet box

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  • You will notice the switch has a strap or yoke that is metal, metal screws metal box, your switch probably doesn't require a physical wire as it has metal to metal connections.
    – Ed Beal
    Jan 9 at 23:12
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You're fine, no need to make any changes here

Switches are permitted to ground through their yokes by NEC 404.9(B):

(B) Grounding. Snap switches, including dimmer and similar control switches, shall be connected to an equipment grounding conductor and shall provide a means to connect metal faceplates to the equipment grounding conductor, whether or not a metal faceplate is installed. Metal faceplates shall be grounded. Snap switches shall be considered to be part of an effective ground-fault current path if either of the following conditions is met:

(1) The switch is mounted with metal screws to a metal box or metal cover that is connected to an equipment grounding conductor or to a nonmetallic box with integral means for connecting to an equipment grounding conductor.

(2) An equipment grounding conductor or equipment bonding jumper is connected to an equipment grounding termination of the snap switch.

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  • Thanks for the info. Good to know as I’m pretty sure the rest of the house is this way. Saves me the extra work then. Jan 10 at 1:03
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You can attach a ground wire correctly by loosening the ground screws in the back and attaching a new ground wire around the screw head. Than attaching this wire to your switch.

If you want you can even loop the wire around the 1st switches ground screw and with enough slack in the ground continue it to the 2nd switches ground screw. No need for a splice nor wire nut.

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    Basically. But it may be easier and less awkward to attach the ground to the screw first and then loop it to the switches. Either way is correct.
    – ojait
    Jan 9 at 23:10
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    I already see 1 wire under each screw 2 wires would be a code violation in the NEC but I don’t know Canada’s requirements
    – Ed Beal
    Jan 9 at 23:11
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    You might want to get a 10/32 self tapping screw and install the wire separately at the back of the box.
    – ojait
    Jan 9 at 23:38
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    No, that's wrong. 1 wire per screw. And, there's no reason whatsoever for a ground wire to a switch here. See TPE's answer. Jan 10 at 3:26
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    Two wires under the same screw, and they look like toggle bolts. Forget the switch and w/e code says, this just pure schlock. One of those holes has threads in it, ideally, and ideally it's filled with a green screw made for the purpose and holding one pigtail.
    – Mazura
    Jan 10 at 18:42
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Since you have a grounded metal box, you don’t need to attach ground to the switch itself if the switch is rated as self-grounding. In this case, the switch is designed to ground itself through the mounting screws.

This is the same for outlets.

If you cannot verify that your switches are self-grounding, then yes, add a pigtail running to the screw in the box.

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    Actually, switches don't even need to be rated for self-grounding. All switches are allowed to ground via the screw heads. Jan 10 at 3:29

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