Home electrical light switch question

[Noah930]

I'm trying to replace a light switch in our kitchen. The lights are on a dimmer switch. Only one switch. The switch/box is bad, as it no longer works reliably (but will sometimes work if the switch itself is wiggled). So I removed the switch (after shutting off the circuit breaker ) and am in the process of replacing it with like equivalent (same manufacturer & model #).

But I noticed that the previous switch has had the green ground wire clipped. (See photo below.) Only the two black wires protruding from the back were pigtailed to existing wiring in the wall. Is that OK? Can I just wire in the new switch like the previous one and cap off the green ground? Or is this a fire waiting to happen?

Replacing the old switch with a new one and reinstalling everything like it was (2 black wires, no connected ground) works the lights, but the switch (or, rather, the metal tabs used to screw it into place) gets warm after a few minutes.

[Cdnone1]

Noah
How old is you house and are there three wires available to wire too.The switch will get warm from the resistance in the dimmer. But it should not get hot.
steve

[carambola]

i know a thing or two about switches
the green wire should be in the bundle os bare wires in the back of the box.
if possible, position the dimmer towards the outside of the box and don't clip off the tabs on the side, the act as a heatsink
all dimmers tend to get warm, they should be sized to the load, i hope you got a 600w dimmer as a 300w may not be able to handle the load. to figure the load count the number of lights this switch works and multiply by the wattage of the lamps.
an old idea about the green wire was that the metal yoke and the 6/32 screws were sufficent to ground the switch if the box was properly grounded, now just put the green wire in with the bundle of bare wires
i hope this helps

[Noah930]

Home is 60+ yrs-old. Kitchen was remodeled at some point in the last 5-10 years, but obviously I don't know who did the work as we only moved in last year. I see no other available wires to hook up to in the jct box, but there are three light fixtures (kitchen/kitchen/dining room) controlled by this jct box. No other light switches in the house work any of these three light fixtures. There are 5 recessed lights being operated by this light switch in question.

The three switches: one dimmer switch (the faulty one) operates 5 recessed lights in the kitchen, another dimmer switch operates 2 recessed lights in the kitchen, and the third switch is a simple on/off one the operates a single light in the dining room.

There's a bundle of wires in the back of the box. I'll have to see where they go/come from. The other two switches aren't connected to any green grounds, either.

The old and new switches are both rated at 600W. The 5 light bulbs controlled by this switch are 120W, each.

[Zeke]

No bare or green ground wire in the box means you have an old house with a non grounded wiring. Attaching the green wire to anything is useless in that circumstance.

For a short time in history, some houses were wired with conduit and a black and a white wire inside (simple circuit). The conduit was supposed to be the ground. You can test for the box for being grounded by using a meter between the hot and the box itself. If you get continuity, you can attach the new green wire to the box directly or by placing it below one of the mounting screws. (Note: this is not necessarily code compliant.)

Grounding has nothing to do with completing a normal circuit. It's a back up safety method. Your dimmer will get warm when the lights are set low. The potential energy not used when reducing voltage is converted to heat.

Use the correct lamps when using dimmers.

[Noah930]

It didn't look too awful when first removing the cover plate. But the more I removed, the bigger the rat's nest that emerged. In the last photo, there is at least one bare wire screwed into the center of the back of the box. Each of the two switches is connected by just 2 wires. The other dimmer switch (controlling two recessed light cans) has had its green ground wire clipped off, as well. The switch in question is the one to the left. I've taped off the end of the green ground temporarily.

[Hugh R]

I'm pretty sure that the twisted bare copper wires are your ground that you connect to the green wire on the switch.

[Cdnone1]

In the olden days you would connect the ground wire directly to the junction box. The metal conduit running thru the house from junction box to junction box back to the main that was connected to the ground pole was suppose to work as a ground for the whole house. It's pretty much useless and as long as the green wire will not make open contact with the other wires you will be fine
Steve

[carambola]

the golden colored wires are your grounds, connect the green to them.
the dimmer is too small for the load, a 600w dimmer is really only good for 480w or 80 of that rating
you could probably get by with 100w lamps or 500w of load
nice job by the way, and next time don't clip off the tabs, if you read the side of the dimmer, it will tell you the load adjustment with one or both sides clipped off
if you can read an injection vial, you should be able to read the sticker on the side

[Cdnone1]

The pictures didn't load for me at first. Hugh is right. The bare wires are your ground. You just don't know if they are connected down stream
Steve

[carambola]

it's actually an interesting box

1½ box which means that the studs are turned on their sides, 5/8th three gang mud ring multiple circuits denoted by the separated neutrals, the old cloth romex for an existing light, fed at the light fixture and back fed through the switch, the 14/2 romex for the lighting circuits
neat box, i think the grounds are tied through the whole circuit

[Hugh R]

If you don't want to get a bigger wattage switch, get dimmable CFLs. They use 1/4 the wattage with the same output. You can get them in soft white, daylight, which is harsh and not "daylight" to me, and others.

[carambola]

i just double checked my memory, by breaking off the tabs you lose 100w of capacity per side removed, it's actually an 80% of 400w dimmer now, or 320w
that will tend to get hot, not a fire hazard, but it will kill the life of the dimmer

[rick-l]

You need more info.

I see

1. a conduit fitting (If it goes back to the main box it provides a safety ground)
2. the box is connected to the bundle of bare copper wires
3. Old cotton covered rubber insulation which may/may not come from an armored cable

I am not sure what the code says about grounding the body of a light switch in a metal grounded box. The dimmer may also need a discrete ground for EMI reasons. It may be fine to provide the safety ground through the mounts, maybe a real off topic electrician will respond.

Breaking off the plaster ears reduces the wattage the dimmer can control???? I haven't hear of that one.

[Normy]

Forget about the green wire.

Your switch isn't grounded. In the future, when you go to sell the house, an inspector will come in and test it; it will go in the report. If you aren't worried about this yourself, then don't worry about it. On the side I work for a small company in Fort Lauderdale, and we have 33 rental units and 4 rental houses. I deal with this all the time, and I cannot count how many times I have installed lights and fans in ceilings where the ground doesn't exist.

Just install your switch, forget about the green wire.

N!