I want to replace a switch with a timer switch, however on checking out the wiring the two original switches have a black wire connecting the two. The switch I want to replace is the rightmost switch. Here's a picture:


Am I correct in thinking that the Hot wire is the bottom wire coming into the left switch, then is connected to the right switch? So when adding my new switch I can use that linked hot wire?

Also, I see ground (copper) wires affixed to screws at the back of the electrical box. Can I simply fasten my new timer switches ground (green) wire onto one of these screws to ground it? Not sure they are long enough to attach to a wire nut

Update: The switch I am adding is a Leviton VPT24-1PZ enter image description here

1 Answer 1


It looks like that's a jumper wire that goes from the left to the right switch? The picture is a little hard to see the details. I would think it reasonable to guess that is the hot wire. When you go to swap out the switch, I would suggest replacing the jumper wire with something a little longer. I find trying to fight those shorter wires is just a nuisance and makes it more cumbersome and hard to tighten those wires down.

You should be able to duplicate the current setup with your existing switch. For a safer and better answer, maybe you can provide a picture of the timer wiring diagram and/or the back of the timer. Some timers are specific on where to connect the hot lead to, while others might not matter.

For your ground wire, yes, you can just ground it to the box directly, provided the incoming service is grounded to the box.

My final piece of advice... I remember being told the #1 cause for home electrical fires is the screws are not tight enough! Be sure to tighten them down!

I hope all that makes sense and didn't confuse you any further.

  • 1
    Yeah, they do test of "how's your torquing", and like 80% of people tighten too loose. Nowadays (NEC 2014?) you're supposed to use a torque screwdriver for every screw. Mar 29, 2019 at 2:01
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    @Harper -- the requirement's found in 110.14(D) which is brand new for the 2017 NEC, but boy oh boy, is it overdue or what! Mar 29, 2019 at 2:35
  • Yes the jumper is left to right. The wire into the left switch + jumper wire is one piece actually, it terminates in the right switch. The switch i'm putting in is a Leviton 24 hour timer switch. leviton.com/en/products/vpt24-1pz I updated my post and attached a wiring diagram
    – Tom
    Mar 29, 2019 at 17:01
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    @Mike I would definitely say the jumper lead is your "Hot" lead and the other is your load. I can't tell how old the wires are, but I kind of think your house isn't grounded. An easy way to tell is if you ever had outlets that were 2-prong, then there is no ground running back to your breaker box. If you don't know, then the age of your house might be an indicator. If you did have 2-prong plugs or the age is common to the no ground era, then no need to worry about how you ground your switch. It won't be regardless of what you do.
    – brehma
    Mar 29, 2019 at 22:51

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