I have four sets of wires coming into a conection box. One is power, one is a light switch, and 2 are feeds to other boxes. I am adding a light to this box. How do I wire it?

It cannot be done. You will have to pull another wire from the box that the switch wire goes to. If there are only two wires in the box then the whole building is probably not run with the nuetral wire and it is therefore going to be more effort than it is worth.

Before you start, turn off the breaker to the wires you are working on.
You should have two 16-2 wires going to your switch, one is the feed, the other will be the line that goes to the light. Put black feed wire onto bottom screw of switch (or top, always be consistent) Put other black from the second wire to the second screw on the switch, this will be your line to the lights with power when switched on. Connect white to white in switch box. The power will come back through the white from the line wire.
Up at the light, make sure you have the 16-2 line wire from the switch, connect the black line from the switch to the two thin black wires from the two bulbs. twist together and put a Marr connector on them. You now have power to the bulbs, the power must come back through the white line 16-2 wire that is in the same sheath from the switch. Connect this white line wire to the two thin bulb wires, twist and Marr them.
Now, you have 2 other 16-2 wires to the octogon light box. My guess is that one is the feed from elsewhere and one is the line to the switch, is that right? Do not connect either of these to the bulbs or else you will bypass the switch.
Below is a diagram but only one bulb, your black line from the switch needs to be marr connected to two blacks, one from each bulb. Remember to connect the bare ground wires together and to the metal box.

Are you talking about a stack switch with two different lights, with two different feeds or, a single switch with two different lights, or something else?A stack swich can handle two different circuits with two different feeds, or two different lights with the same feed. If you have two lights with the same feeds you want to put your power source on the side with black terminal and your switch leg on the other side and, tie your neutral in with the other neutrals, ground in with other grounds.. If you are moving the switch to a bathroom and have tied your neutral into a GFI circuit, this could be causing your problem. For two separate feeds, you would break tab joining the two black terminals on feed side of switch, and hook your two feeds on both terminals of switch, then you will have to break tab on switch side and do the same. This sounds like a neutral or a ground problem or, if when you put your switch in the box, you may have a bare ground touching the feed terminal on switch, if breaker pops right away, or, ground may be touching switch leg side of switch, if it pops when you turn switch on. Let me know if your dealing with a bathroom situation, if you are moving your switch into another existing box, or if you added a box. Try to explain to me how you provided, your power and how you got your switch leg to a new box if that is what you did.

How many sets of wires are coming into the box?
If the box is in the middle of the circuit you will have a power-source black & white wire coming in and a power-source black & white wire going out. And in this case for the switch - there must be a black and a white wire going to a light.

Typically with a switch/outlet combination all the white wires will splice together with a white pig-tail wire to feed the neutral side of the device. The two black wires from the power-source will splice together with a black pig-tail and feed the hot-side of the device. The black wire going to the light will go on one side of the switch.

Looking at outlet/switch device from the front the large slot side of the outlet will be the neutral side and the smaller outlet slot will be the hot side. The neutral side screws will be steel colored and the hot side screws will be brass colored. The white wires will go to the neutral side steel colored screws, and the black wires will go on the hot side brass colored screws on the outlet.

The black wire comig into the box from the light is called a switchleg and goes to a brass screw on one side of the switch. The brass screw on the otherside of the switch will be for the black wire coming from the power-source.

Hope this helps - and please:

TURN THE BREAKER OFF BEFORE YOU START WORKING WITH THE WIRES!

If I understand correctly, you are replacing a single switch that has two wires.
You want to install a switch/plug-gfci similar to one shown below.

You are working on wires inside a box:
To wire this kind of device you need at least 2 cables entering the box.
Each cable has a black-white-ground wire.
Cable 1) One cable comes from breaker box. This is the Hot cable
Hot cable has black-hot-from-breaker & white-neutral-from-breaker

Cable 2) One cable goes to the Load (light, fan motor). This wire is controlled by the switch. This is the Load cable
Load cable has black-to-load & white-to-load.



Leviton combo GFCI and Switch
There are 2 screws on either side of switch
There are 2 screws to either side of plug
There are two wires on back of device

2 screws on either side of switch: there is a brass-colored screw and silver-colored screw.
Black-hot-from-breaker connects to brass colored screw on side of switch
White-neutral-from-breaker connects to silver colored screw on side of switch

2 black wires on back of device
Black-to-load connects to black wire on same side of switch as brass-colored screws
White-to-load connects to black wire on same side of switch as silver-colored screws

2 screws on either side of plug
These screws are used when your box is a 'junction' box that feeds wires forward to another box ... for example you have 4 receptacles in a room, the cable enters first box and then goes to the next box and to the next box. Suppose your switch was one of the boxes. Wire arrives from a previous box (this is the Hot cable, every box has 1 Hot cable). Your switch box sends one cable to the Load (light, fan etc), but it also sends another cable to the next box which has a receptacle or another switch.
If your box has a third cable that feeds forward to other boxes, then the screws on either side of plug are used. The black-to-next-box goes to brass screw. The white-to-next-box connects to silver screw.
And all further boxes and devices are protected by the GFCI device.

If you need more information, please answer back and I will help.

While there are many ways to wire 3-way switches, the most common way is to bring a 2-wire/with ground HOT and neutral cable (from circuit breaker or source) into one switch box and a 2-wire/with ground LOAD cable (to light) into the other switch box. Then a 3-wire/with ground cable is ran between both switch boxes.

The PR 180 _must_ be installed at the switch box the has the cable that goes to the LOAD. I suspect that you have the PR 180 installed in the switch box that contains the HOT feed.

Unfortunately, the solution is to install the PR 180 at the downstairs location and have the normal 3-way switch at the top.

Another solution would be to install a Leviton 1PP15-1L at the switch box that has the HOT feed and a Leviton 1PP0R-1L at the switch box the has the LOAD cable. This, of course will result in a sensor at each location.

before u start make sure power is off before working with electrical lines ---start with the 12/2 coming into box black [power] white [ground-neutral] and u will have 3 separate lines for the lights so u will have 4 lines total coming in the box== with the 3 light lines take the white and strip back the plastic and connect [wire nut] all 3 to the 12/2 white line --now take the 12/2 black line and connect it to the first switch gold color screw- bottom screw -now take some wire about 2-3 inch strip both ends and connect from the 12/2 black wire connection on the switch and connect to the gold /bottom of switch 2 than do the same for switch 3 connecting the wire from switch 2 so u will have power feeding all 3 switches-- now connect the black lines for the lights to the other side of each switch and ur done

The white wire in your ceiling box is USUALLY the neutral wire. Green or bare wires are ground wires. Any other colored wires are generally hot, switched or unswitched. If changing the position of a wall switch makes a white wire hot, it is NOT a neutral wire. You need a test light, generally an inexpensive neon test light available at any hardware store, and a book on basic wiring would help. To control the fan and light separately, assuming you have not installed a wireless control, you need two switches, one for the fan and one for the light. If you do not have these, you need a wireless control unless you have a spare wire in the wall switch box or you need to be satisfied with controlling the separate functions with the pull chains. Check the ceiling box wires. Put one lead on the ground wire or, if you have steel boxes, on the box. Remove the wire nuts on the other wires, being careful not to touch any wires or touch any of the wires to each other or the side of a metal box. Touch the other lead to the other wires, one by one. If the light comes on, the wire is hot. Try the wall switch(es) on and off and see what changes. To make the fan or light work it has to be hooked up to a neutral wire (white, never hot regardless of any switch positions) and a hot wire. The same is true for the light kit. If you do not have or want two wall switches, one for the light and one for the fan, you need to identify the wire that is hot when you turn on the wall switch and hook it up to the black (fan) wire AND the blue (light)wire. You then control both with the single wall switch in conjunction with the pull chains. If you have two switches in the same wall box, and they make two different wires hot in the ceiling box, hook one to the black fan wire and one to the blue light wire. If you're set up with only one switch, and you're lucky, you may have an extra wire in the same cable from the ceiling box to the wall box, with a wire nut on each end. In that case, install a second switch for the light (or a combination switch designed to control both a fan and light). Hook the hot wire from the wall box to both switches (or the hot terminal on the combination switch) and the other two wires to the other two terminals that go to the ceiling box to feed the light and fan. Never use a light dimmer switch to control a fan or a fan speed switch to control a light. If two or more switches in different areas controlled the original fixture in the ceiling box, things can be complicated. If the same wall switch makes two different wires hot depending on it's position, for example, it's a three or four way switch. The above description also assumes the wall box is fed from the ceiling box, but the opposite may be true. There may also be wires in either box that are feeding other circuits in the house. Electricity can kill or burn down your house. If unsure of what you are doing, hire a licensed electrician. Also be aware that if you touch the leads of the test light to two wires that are both hot, the light may not come on. Always test with one lead on a ground or a wire that you are sure is a neutral wire. I recommend tuning off the power to all the circuits in the boxes that you are working on, after you have determined what the wires are, by shutting off the circuit breaker(s) or removing the fuse(s). There may be more than one circuit in a box.

The proper way to wire two switches in a 2 gang switch box to control each light separately is as follows:

1. Make sure you have the power turned off at the breaker for this box.
2. Take the HOT (common, black wire) FEED wire and add (2) pieces of black wires to it with a wire nut.
3. Now you can put one of each of these black wires to the bottom screw of each light switch to provide power to both switches separately
4. Connect each separate wire to the (2) different lights to the top screw of each switch.
5. Twist all the bare ground wires together, leaving at least 7-8 inches at the ends untwisted for at least 2-3 of these wires.
6. Take (2) of these ground wires and connect them to the ground screws on each separate switch. If it is a metal box these area in, connect one ground wire to the box with a green grounding screw also, if not, cut off the extra ground lead near the twisted bunch.
7. Now twist all white (netural) wires together and install them all under one wire nut.
8. Make sure the bare wires are not near or touching the HOT screws and fasten the switches to the box.

You now have an approved and legal wiring for (2) separate light switches using the one power source (FEED) already in the box.

Make sure you turn off the power at the power panel.
If you are lucky you will find the following in the electrical box behind the light:

1. A black wire that brings power from the fuse/breaker panel--connected directly to one or two other (black) wires (not to the light).
2. A white wire from the panel--connected to one or more white wires including one to the light.
3. A black or white (maybe taped black) wire that comes from the switch and is connected to the light.
4. A green or bare wire connected to the box and maybe also to the light.

If this is the case then you can run a new cable to a new electrical box in the wall for the GFI. Connect the new black wire to the Line In terminal/black wire of the GFI outlet and to the group of black wires in (1) above. Connect the new white wire to the Neutral terminal/white wire of the GFI outlet and to the group of white wires in (2) above. Connect the new green/bare wire to the Ground terminal/green wire of the GFI outlet and to the original box or ground wire. If there is a Load/Feed through wire on the GFI outlet, tape the end of it and do not use.
If the black and white wires described in (1) and (2) above do not appear in the electrical box at the light then they are probably in the switch box and there will be only one black wire and one white wire that connect to the light on the wall. In that case you will need to run a new cable from the switch box to the new outlet. You will not be able to wire the new outlet from the existing electrical box at the light unless you do it through the switch and it will not be on unless the switch is on.