[thinksincode]

Hi all,

I'm getting braver, trying to replace a light switch today. It's a standard single pole switch inside a box with 3 other switches. I have a few wiring questions, though, so I make sure I do the right thing.

The timer switch I'm installing is an Intermatic ST01. There are four wires - a red wire, black wire, blue wire, and green wire.

I am following this instruction video to install the switch: http://www.youtube.com/watch?v=RErdw4_Lc0M

Per the instructions, I have capped the red wire because it's only used for a 3 way switch. No problem there. I'm then supposed to connect the black wire to one of the black wires on my existing switch, and the blue wire to the other black wire on my existing switch. Here's my first question. As you can see in the attached pictures, one terminal of my existing switch has two wires connected to the same screw. I'm no electrician, but that doesn't look right. How do I proceed here? Should I connect these two wires and the black wire from the timer switch together in one wire nut? It seems, logically, that that would be the same electrical path.

My second question is about a ground wire. The instructions say to connect the green wire on the timer switch to the ground wire. As you can see in the photos, there is a bare wire that I assume is the ground wire, but it wasn't connected to the original switch. How would I connect this to the ground wire on my timer switch? I am probably incorrect, but it seems like I would cut that ground wire, and pigtail them together with the green ground wire on the timer switch with another wire nut.

Does this make sense? Or am I completely wrong? First switch replacement so I'm a little unsure. :huh:

 

[hammerlane]

Doesnt look like a double tap. That looks like one wire wrapped around that terminal. But looks like someone took the insulation of it somewhere midway and then wrapped it around the terminal.

 

[thinksincode]

After taking a closer look, I think you're right! What would I do in this situation?

 

[hammerlane]

Like this:

 

[hammerlane]

I see you responded already. Is that wrapped wire the ALWAYS HOT wire or is it the switched hot??

 

[thinksincode]

Hang on, I'll check. What's the easiest way to check, turn the power back on and test each wire with a multimeter?

 

[thinksincode]

The wrapped wire is the ALWAYS HOT wire.

 

[hammerlane]

yes keep power to circuit but have light off..with light off check from one terminal to a neutral or ground.

with light still off check from other terminal to neutral or ground.

whichever terminal shows about 115V that is your always HOT

 

[hammerlane]

you can cut it at the wrap point then use a pigtail and wire nut.

 

[thinksincode]

That's what I figured. Thanks for the diagram. Is the "pigtail" the wire coming from the new timer switch?
Should I do the same thing for the ground wire? cut it and join it with the ground wire from the timer switch? (the current switch is not connected to the ground wire)

 

[thinksincode]

OK, here's what I did. I didn't want to go cutting more wires, so for now I left the ground not connected. I cut the hot wire where you suggested and joined the two halves, plus the black wire from the timer switch, in a wire nut. I joined the other black wire with the blue wire from the timer switch, in a wire nut. Then put electrical tape around those.

I didn't do anything with the green ground wire on the timer switch until I'm sure what to do, so for now I just shoved that into the box with the other wires. Should I have capped that with a wire nut also?

I turned the power on and tested it, and the switch seems to work. I just want to make sure I didn't make an amateur mistake and burn my house down.

I noticed that the solid copper wire looked a little chipped/dinged (first picture), from the pliers. Is this dangerous?

 

[hammerlane]

I didn't do anything with the green ground wire on the timer switch until I'm sure what to do, so for now I just shoved that into the box with the other wires. Should I have capped that with a wire nut also?

I noticed that the solid copper wire looked a little chipped/dinged (first picture), from the pliers. Is this dangerous?

I prob would of put a wire nut on that unused ground but if you are positive its not gonna flop around in the box and touch a hot or neutral wire it would be fine. That small nick on that wire looks not too bad.

 

[eastcoastsparky]

All of the ground is bare, so putting a wire nut on it is somewhat useless

 

[hammerlane]

All of the ground is bare, so putting a wire nut on it is somewhat useless

Not the ground wire coming from the timer which is what I think he was referring to.

 

[thinksincode]

I attached the green ground wire from the timer switch to a screw in the electrical box. But I'm not sure if this is acceptable. Does this look safe? Or am I asking for trouble?

 

[clydesdale]

I attached the green ground wire from the timer switch to a screw in the electrical box. But I'm not sure if this is acceptable. Does this look safe? Or am I asking for trouble?

In the back of the box there should be a hole that accepts a 10-32 grounding screw which is typically green in color. That would be the traditional place to ground switches to the box. You can buy boxes of the grounding screws at any supply house or big box store. They also sell pre made ground pigtails with both stranded and solid wire that are very convenient to use as well. I wouldn't use the cable clamp - it may be legal though - someone else who knows the code well can jump in and comment.

 

[thinksincode]

I think I see the hole that you mean. Sorry for the blurry picture, but it's the only one where it's not obscured by the wires. The hole is right in the middle. Is that where I would attach a grounding screw?

 

[clydesdale]

I think I see the hole that you mean. Sorry for the blurry picture, but it's the only one where it's not obscured by the wires. The hole is right in the middle. Is that where I would attach a grounding screw?

Looks like a good candidate. Do you have a 10-32 ground screw? Also note that sometimes when they tap (thread) those holes they are not perfect so it may take a little bit of work.

 

[thinksincode]

I don't have any handy, no.

I actually have decided to call an electrician I know to come re-do this properly after all. If I have this many questions, I am probably in over my head. I appreciate all the help!

 

[hammerlane]

That does nothing unless that box is somehow grounded itself. It is no more asking for trouble than leaving that ground wire from the switch unattached.
The ground to the switch does not affect functionality. But think of the ground wire as an airbag in a vehicle. If you need the airbag in a vehicle you are going to hope it is there. Same as ground on a device