Is a ground required when replacing an old light switch?

Question

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?

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.

With switches and outlet pulled out.

Answer 1

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.

Answer 2

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.

Answer 3

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.