Basic switch wiring?

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  #1  
Old 02-26-05, 07:25 PM
prw
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Basic switch wiring?

I am replacing a standard single switch in the garage that operates an outside light. This is the only switch that controls this light. When I removed the coverplate, I discovered a) all of the wiring is white with what appears to be streaks of black paint in places. b) two of the wires are inserted into the "push in" type receptacles on the back of the switch, while one wire is attached to the bottom screw terminal and the top screw terminal has nothing attached. How do I tell what are the normal hot wires and which is the netural under this setup? I need to replace the switch but am hesitant without knowing exactly what the current wires are doing - - - hard to do since they are all the exact same color????

THANKS
 
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  #2  
Old 02-26-05, 08:01 PM
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We need more precision. You identified three wires that are attached to the switch. Are there also other wires in the box? If so, how many and how are they connected?

Note that all wires attached to a switch are hot, either switched hots or unswitched hots.

Note also that power passes through this box and on to other things that are not controlled by this switch.

Also, please tell us why you are replacing this switch. Is it defective? Also note that if you simply connect the new switch as the old one was connected, you don't need the answers to any of your questions.
 
  #3  
Old 02-27-05, 05:52 AM
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My suspicion is that you have three cables coming into this switch. One cable brings power in, one brings power out and one brings switched power to the outdoor light. If I am correct, there will be three wires connected together with a wire nut, one from each cable. These are the neutrals.

Under normal situations, a neutral wire is not connected to a switch. Exceptions are (sometimes) a switch that contains a light.

Examine the switch. You should see that each "push in" connector is located near one of the screw terminals.

Attach the "pushed in" wire and the wire attached to the screw terminal near it to one of the screw terminals on your new switch. Use a wire nut and a pigtail, as you are not allowed to place two wires under a single screw. Attach the "pushed in" wire that has nothing on the screw terminal near it to the other screw terminal.

Do not use the "push in" connectors on the new switch. These have a tendency to fail over time.

However, if you do not have the three neutral wires connected together with a wire nut in the back of the box, then do not follow the above directions.
 
  #4  
Old 02-27-05, 02:02 PM
prw
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More info

This switch is being replace because I wanted to install a motion sensor control over the outside light. The setup is simply the motion senser posted outside and a new swith to replace the old swith. The new switch has two black wires on the right side of the switch and a green ground on the left side of the switch. The instructions say to connect the two black wires to the two load wires in the circuit and connect the green to the neutral in the switch. Under the set up I described, I can't tell which 2 are load and which 1 is neutral. There are no other wires in the old switch attached except for there 3; the 2 "push in" and 1 to the bottom screw. Per the earlier post, I did see a wire nut in the very back of the receptacle that may be a pig tail of sorts? Thanks for all the help.
 
  #5  
Old 02-27-05, 04:33 PM
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The instructions say to connect the two black wires to the two load wires in the circuit and connect the green to the neutral in the switch
No they don't. Can you quote this to us exactly?

Note that two wires (one poked into a hole and one on the screw closest to that hole) should be connected to the same wire from your new switch. The third wire goes to the other wire from your new switch. The green wire on the new switch should connect to the grounding wires (bare or green only!) in the box, if any. Don't even consider for a split second connecting that green wire to anything else. That might kill you.
 
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