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I need to replace a switch that controls a single light source in a bathroom.

The switch has two wires connected to it. I bought a replacement switch that has two screws (one for each wire), and a green ground screw.

Is it OK to connect just the two wires to the new switch and have the green ground screw unconnected?

This is not a remodel. Just trying to replace a switch that's broken.

EDIT: strangely, I didn't see a ground screw on the original switch. Was this permissable at some time?

EDIT 2: Picture as requested. The left switch is for a light source and is the broken one. Right switch is for a fan. The two switches are on the same circuit. The outlet is on a separate circuit.

I can't tell if the box is metal. It seems plastic but could be painted metal I suppose.

Broken switch

EDIT 3: With switches and outlet pulled out.

Switch and Outlet Connections

jglouie
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3 Answers3

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Because you are replacing the switch, not installing a new switch, you can get away without a ground. You should install a nonconducting, noncombustible faceplate though.

NEC 2008
404.9 (B) Exception. Where no means exists within the snapswitch enclosure for connecting to the equipment grounding conductor or where the wiring method does not include or provide an equipment grounding conductor, a snap switch without a connection to an equipment grounding conductor shall be permitted for replacement purposes only. A snap switch wired under the provisions of this exception and located within reach of earth, grade, conducting floors, or other conducting surfaces shall be provided with a faceplate of nonconducting, noncombustible material or shall be protected by a ground-fault circuit interrupter.

If you were installing a new switch, you would be required to provide an equipment grounding conductor at the outlet. And the switch would have to be properly grounded, in accordance with the National Electrical Code (NEC).

There was a time when an equipment grounding conductor was not required at each outlet, so it's fairly common to come across this situation (especially when working in older homes). You'll often see exceptions like this written into codes, so as not to require a full rewire just to replace a switch.

New info, Better answer

If you are replacing a switch a ground is not required, as per the above exception. However, if you're installing a switch; replacement or otherwise, into a metal box that is grounded. The switch will be ground via the devices yoke and mounting screws. So if the metal box is grounded, the switch is also grounded.

If the box is nonmetallic, and there are other grounded devices within the same enclosure. You can ground the new switch using a jumper between the switches grounding screw, and the other devices grounding screw. Just keep in mind, that you can't terminate two conductors under a single screw terminal. So if you do this, you'll have to use pigtails to make the connection between the devices.

Community
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Tester101
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  • There's an outlet in the same box that should (I hope??) have a ground wire. It is on a separate circuit though. It sounds like the exception wouldn't apply in this case then because a ground wire wound be in the enclosure. Is that correct? – jglouie Dec 07 '12 at 20:43
  • @LemonBeagle Is it a grounded receptacle (3 prong), or ungrounded (2 prong)? If the receptacle was installed at the same time as the switch, it may not have a ground. – Tester101 Dec 07 '12 at 20:46
  • If it is grounded, is it up to code to use the ground from the other circuit to link in his light switch? – The Evil Greebo Dec 07 '12 at 20:46
  • It's a 3 prong outlet, although it is a separate circuit (had to turn off a different breaker). – jglouie Dec 07 '12 at 20:48
  • @LemonBeagle Does it have a grounding conductor connected to it? Is it a metal box? – Tester101 Dec 07 '12 at 20:49
  • It's a moving target question! – The Evil Greebo Dec 07 '12 at 20:54
  • It seems to me this answer also talks as if the switch is not grounded at all. I've come across the following situation many times: the box is grounded, and the switch (which is mostly metal) is screwed into the box which provides a conductive path so all the metal is grounded. The newer switches add a ground screw to the metal body, so now the switch can be grounded via a dedicated ground wire IN ADDITION to the screws holding it in the box. In this situation, is it necessary, by code, to connect this ground wire? Is it different for new vs retrofit? – gregmac Dec 07 '12 at 21:29
  • @LemonBeagle See my edit. – Tester101 Dec 07 '12 at 21:58
  • The box in the pic sure looks like a plastic box. There is a ground conductor on the outlet, so I agree with Evil, bring the ground to each switch, and install a GFIC if not already protected upstream. – shirlock homes Dec 08 '12 at 11:25
  • @Tester101 - I get what you mean, but others may not - this is a fragment: "However, if you're installing a switch; replacement or otherwise, into a metal box that is grounded." (Sorry, I'm an engineer, and I have to point these things out all the time. Just thinking of the inexperienced and non-native readers). – Scott Prive Jan 19 '19 at 14:17
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Ok, now that we've got all the questions answered.

Get yerself a spare bit of unshielded 14ga copper wire.

Connect the ground screw from the new switch to the ground terminal on the grounded outlet.

You're grounded.

The Evil Greebo
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    Since it is in a bath you might want to consider installing a GFI outlet while everything is out – mikes Dec 07 '12 at 21:48
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    Good advice - only if it's not already chained to an existing GFCI though. – The Evil Greebo Dec 08 '12 at 01:33
  • "from the new switch to the ground terminal on the grounded outlet" -- is is really code compliant to connect TWO wires to a ground screw? I know it's "just a ground" but I thought that it was 1-wire-per-screw (unless they're wire from behind "stab and clamp" side screws). I think it would be more secure to wire 1 ground per ground screw, and splice them in the box. But my question is, what is NEC code say about this? – Scott Prive Jan 19 '19 at 16:36
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from the photo, the outlet clearly has a ground and should be spliced and then the ground run to each switch and the original outlet.

user13898
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