Circuit Breakers - Ceiling Fans - Outlets and Switches - New Wiring and Rewiring - Home Wiring - Light Switches - GFCI Wiring - General Electrical - Power and Voltage
Q. I currently have a wall switch that controls an outlet. I want to add another switch beside the first to control a new overhead light separately. Is there any way to wire the new switch to the existing circuit on the existing switch?A. You may or may not be able to add a second switch and then run power to your light with the present wiring. As GWIZ stated, the answer depends on whether there is a neutral wire in the switch box. If you only have a switch loop from the receptacle, then you have no neutral, and you cannot do what you want. If you do have a neutral, then you can do what you wish.
If you do not have the necessary neutral, you could still do what you want if you replace the wire from the receptacle to the switch. Another option is that you could rewire the receptacle so that it is un-switched, and then use the existing wiring and the existing switch for the new light.
Q. I am in the process of replacing the socket/switch assembly for a 3-way floor lamp. I successfully removed the old socket/switch assembly, the two wires are exposed, and now I can't figure out to which posts of the new socket/switch each of these wires should be connected. Does it matter? Is there an easy way to determine this?
A. If you get it right, the shell of the socket will measure zero volts to ground and the button at the bottom of the socket will measure 120 volts to ground. If you get it backwards, you'll get the opposite readings.
Q. What is the distance from the floor to a light switch in the bathroom? I'm remodeling our old house and can't seem to find this info.
A. The switches can be placed at whatever height suits your needs. Generally, they are placed to match the other switches in the house.
Q. How do I tell the difference between a three way and a regular on/off or two-way switch?
A. The simplest way is to look at the lever on the switch. If it says on and off, then it's a single-pole switch. If the lever is blank, then it's either a three-way or a four-way.
Q. My power begins at Switch #1. From there I will run 12/3 (with traveler) to switch #2. Then my light fixture will be at the end. Therefore, from switch #2, I only need run 12/2. Does this sound correct? The fixture will be at the end of the circuit.
A. ===S1~~~~~~~~~~S2=====LIGHT
= is 12/2 w/g and ~~~ is 12/3 w/g
You should have a (2) wire coming into the S1 box so the black from the feed will go to the Black screw or (common) screw on the 3-way switch. The white wire coming into the S1 from the feed will connect with the white wire in the 12/3 wire (splice them together). The Red and Black wire at the S1 in the 12/3 will go to the (2) remaining screws on the S1.
Notice: Make sure you tie all your grounds together and ground your switches with a pigtail from the ground groupings.
In your S2 box, you have the 12/3 coming in from S1. You are going to take the Red and Black to the SAME two screws on the S2 3-way switch, Wire nut the WHITE from the 12/3 to the white 12/2 going to the light.
Now take the Black wire from the 12/2 (going to the light) and put it to the Black screw (common) on the 3-way switch. You should be all set. Don't forget to make up your grounds.
Helpful tips: Wires go on screws in a CLOCKWISE direction only. Do not forget to ground your switches correctly and NEVER work on a LIVE circuit. Make sure you shut off the power and test it before working on it.
Q. I am putting in a new section in my basement and have done a good job on everything else. I have a very good electrical book explaining a 3-way switch with one light on it, but not with three lights. I will have power going to the switch then 12/3 to the first light, second light, third light, then on to the other switch. My confusion comes in here: do I simply tail the whites off? The reds are wire nut until the last switch?
A. You cannot do it the way you are suggesting. Run 12-3 from the first switch to the first light. Then run 12-3 to the second switch. When this works, run 12-2 from the first light to the second light and then to the third light. If you want to do it the way you suggest, you would need 12-4 between the lights, not 12-3.
Q. I just moved a 3-way switch. During the move, I noticed something strange. The poles of the 3-way had a white, red and black connected. The white wasn't remarked black. Should it have been? It is my understanding that a white can carry voltage only if it is remarked with black tape or black marker. Should I remark the white?
A. The white is most likely being used as one of the travelers and it should be marked black; however, it isn't very uncommon to find unmarked white wires that are being used as hot wires. It's not a big issue, but by code it should be marked. Any electrician would recognize it as a hot wire but homeowners may not - but then again most homeowners don't know this bit of information anyway.
Q. 1. I just replaced three light switches in our bathroom because the old ones were dingy (paint, dirt, etc). When I attach the wall plate to box, the switches are too far back. What do I need to do in order to get the switch flush with the wall plate yet screwed in tightly?
2. The prior owners of the home did a mediocre on some things. They installed track lighting but never completed the job (they installed two lights and not the third). Therefore, I have possibly live wires dangling out of the ceiling. What I would like to do is cap them somehow, stick them back in the ceiling, and Spackle the hole. What is the safest way to do this?
A. 1. You tightened the screws too tight. The ears of the switches should be tight against the wallboard, but not so tight to be bent.
2. You cannot stick live wires back in the wall. You can either find the other end or stick both ends into the wall, or you can install a junction box with a cover and stick the end of the wires in the junction box.
Q. I am replacing a few of my switches to set up home automation, and the switches I purchased are not neutral wire compliment switches.
1) Do I need neutral wire compliment switches?
2) What are the benefits and disadvantages of having a neutral wire?
3) Should I send these back and get the more expensive neutral wire compliment switches?
A. It looks like a neutral connection in your photo. In a 120v circuit, a switch is wired in series with what it controls; without a neutral you have no circuit. Only in certain industrial circumstances is a neutral allowed to be switched.
Benefits of a neutral wire: A 3-wire Branch-Circuit cable with a Neutral conductor, which extends from the breaker-panel can supply the power-equivalent of two 2-wire cables. In commercial/industrial wiring, a 4-wire Branch-Circuit with a Neutral conductor can supply the power equivalent of three 2-wire cables.
The White wire is the "Identified" circuit-conductor, and is also the "Grounded" circuit-conductor, the NEC requiring all Grounded circuit-conductors to be identified by the color White, and NO OTHER color.
One "exception" often used in residential wiring is the White wire of a 2-wire cable, which is connected between a switch-controlled fixture and the switch. For this type of connection, the White connects to the Black wire of a "Feed-In" cable in the fixture outlet-box, and then extends power to the terminal of the switch that controls the fixture, the power extended back to the fixture via the Black wire when the switch is "On". The point is that not all White wires in residential wiring are Grounded/ Neutral conductors if there are connections to switches in an outlet-box.
Q. I just bought a co-op and I'm in the process of renovating it. All of the outlets are black and I'll be changing them out to white, simple enough. These are of course two prong. Can I simply install three prongs in their place or do I need to make some sort of major change?
Second question: A switch on the wall controls the outlet where I plan to place my TV. Both the top and bottom are receptacle. I want the TV to have constant power. Is it possible to have only one of the receptacles powered by the wall switch? Is this a DIY or should I call an electrician?
A. You can install three prong receptacles if there is a ground wire running to the receptacles or if the receptacle is grounded in some other approved manner, or if you provide GFCI protection to the receptacles in some way. I suggest that you use two prong receptacles for the replacements. Whether or not you can make half the receptacle unswitched or not depends on the existing wiring. If you report on the wiring at the receptacle and at the switch, we can help you decide if this is possible.
Q. My house's previous owner did some rewiring with 12/2 to lights and receptacles. A few lights are spliced into the 12/2 wiring with 14/2. Is this safe? I am also going to replace a lot of the old cloth covered wiring that is left. They left behind about 300ft. of 12/2 wiring. Is this OK to use for rewiring the remaining lights and receptacles or should I get 14/2?
A. You most certainly need to make sure the circuit that the previous owners tapped into is protected with a 15A OCPD versus a 20A if the circuit has multiple size wire on it. You need to protect it for the smallest size wire protection, which in your case is 14 AWG, so it needs to be 15A.
As for rewiring, you can certainly use 12 AWG if you would like, and many are doing it today. But as a Electrical Contractor I still run 14 AWG where I can in regards to lighting circuits, bedrooms and so on. Just remember, if you are going to be tapping into 20A circuits, you need to do so with the same size wire, otherwise you will need to adjust some breakers.
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