I just replaced an old dimmer switch (no ground wire) with a new one (with green ground wire). Is this safe?
The wires I found in the wall were red, black, and white. I connected the first wire of the dimmer switch with the red and the other with the black wire.
I didn't know what to do with the green ground wire so I just put a wire nut on it and wrapped it with electrical tape. Is this a fire hazard? I need your help.
My dimmer switch seems to be working just fine.
One last thing, do you have any idea what the WHITE wire is for?
Answers:
Okay, first off, the purpose of the Green Wire is in case the current carrying wires somehow "short' against the metal mounting portion of the switch, which will then become live (and dangerous) if it does not have a path to allow the current to return to the Circuit breaker (or fuse) which will immediately turn off the power to the switch.
Instead, that portion of the switch if touched, current will seek a path through that person, (if they are grounded, which can happen numerous ways) and harm them. (this happens rarely, however, because it has happened, the ground (green wire) is now required on switches, especially since most home electrical outlet or switch boxes are non-metallic and carry no current).
There should have been "BARE" wires tied together with a crimp or wire nut which you should have connected it to.
The White wire is the Neutral wire. This is the usual path where the "Used" electrical current returns to the power company, which can be more dangerous than the "power supplying" and "switch leg" wires (Red and Black in your case).
Other answers:
White wires are usually grounded conductors (neutral wires). When dealing with a switch though they can be ungrounded conductors (hot wires) as per the NEC. To determine which it is you need to look at the application, are there two cables in the box, was this switch used for a fan with a light or in a three-way application, and was the white wire connected to the old switch.
If this is an older home there may not be a grounding conductor (bare wire) to connect the green grounding wire to on your new switch to. If this is the case you should cut it off.
If any of this confuses you then you should ask a friend who understands electrical systems to come look at it. There is a reason why electricians are paid so well.
White wires are usually grounded conductors (neutral wires). When dealing with a switch though they can be ungrounded conductors (hot wires) as per the NEC. To determine which it is you need to look at the application, are there two cables in the box, was this switch used for a fan with a light or in a three-way application, and was the white wire connected to the old switch.
If this is an older home there may not be a grounding conductor (bare wire) to connect the green grounding wire to on your new switch to. If this is the case you should cut it off.
If any of this confuses you then you should ask a friend who understands electrical systems to come look at it. There is a reason why electricians are paid so well.