Seperate Electrical Problems

Discussion in 'Electrical and Wiring' started by brewer79, Feb 17, 2014.

  1. Feb 17, 2014 #1

    brewer79

    brewer79

    brewer79

    Junior Member

    Joined:
    Feb 17, 2014
    Messages:
    3
    Likes Received:
    0
    I have two electrical problems, they are separate and don't run on the same circuit.

    The first, and I think is the easiest, is my outdoor porch light. It's controlled by a switch inside. The light no longer turns on, and yes it's not the bulb. I took the switch out and replaced it but apparently the outlet isn't hot anymore. Is this going to be a major fix?

    The second problem involves a three way switch downstairs. Only one switch works properly right now. I tried to isolate the hot wire but only found that it's hot in one box, not the other. I'm thinking that might be a major problem.

    Any advice would be greatly appreciated.
     
  2. Feb 17, 2014 #2

    nealtw

    nealtw

    nealtw

    Contractor retired

    Joined:
    Nov 4, 2010
    Messages:
    23,897
    Likes Received:
    3,117
    Welcome to the site.
    Squirals in the attic????
     
  3. Feb 17, 2014 #3

    Wuzzat?

    Wuzzat?

    Wuzzat?

    Well-Known Member Sponsor

    Joined:
    Jan 20, 2010
    Messages:
    2,471
    Likes Received:
    175
    A Less so if you know what all else is on the same breaker. You might also start looking for a tripped GFCI somewhere.

    B Three way switches have Phantom Voltages
    https://www.nema.org/Technical/Documents/Bull_88_reaffirmed_12_15_11.pdf
    which will really confuse because the voltage you read depends on the type of meter you use.
    I recommend a 120v, 100w or larger incand bulb in a socket with pigtail leads as a tester. Almost any hardware store carries this item.
    If you put your multimeter across the bulb you have made a low impedance meter as mentioned in the link.

    You'll need to figure out which of the three switch terminals in the switches are the wiper/common terminals and which are the switched terminals. Usually the wiper screw is a different color than the other two screws.
    If you don't like troubleshooting of the very tedious kind, take a gamble and replace both switches. But, I recommend the troubleshooting! :D
    BTW, test each switch before install with a multimeter.

    Good problem, in any case.
     
    Last edited: Feb 17, 2014
  4. Feb 17, 2014 #4

    bud16415

    bud16415

    bud16415

    Fixer Upper Staff Member Admin Moderator

    Joined:
    Feb 5, 2013
    Messages:
    4,657
    Likes Received:
    1,598
    I don’t see why you would get more phantom voltages off a 3way than any other home wiring circuit. Don’t use a homemade light bulb tester if you don’t want to use a meter then buy a little two wire voltage tester with a light.

    To the OP Google 3way switch circuit and you will find many illustrations on how they are wired. Its pretty straight forward once you see it. As to your outside light I don’t think it’s the wires in the house gone bad I would start by checking the connections in the light or look for voltage at the wires at the light. Based on what you have already done.
     
    CallMeVilla likes this.
  5. Feb 17, 2014 #5

    brewer79

    brewer79

    brewer79

    Junior Member

    Joined:
    Feb 17, 2014
    Messages:
    3
    Likes Received:
    0
    Thanks for the help so far folks.

    The three way switch, I had replaced the switches (both at the same time, and yes they were three way switch replacements). The one switch still didn't register any type of voltage. I'm using a pretty heavy duty multimeter that does a whole bunch of stuff. With the wires isolated on both sides and the circuit on, nothing registers hot on the one box. The other box registers though. I'll check it out again in the warmer weather and see what happens.

    As far as the porch light, no critters in the house (at least I hope not). I think the socket might be corroded out because it's so old, but would that affect the reading at the switch?
     
  6. Feb 17, 2014 #6

    nealtw

    nealtw

    nealtw

    Contractor retired

    Joined:
    Nov 4, 2010
    Messages:
    23,897
    Likes Received:
    3,117
    On the three ways did you replace wire for wire when you removed the old ones?
    The outside light is more likely to have loose connection at the light box if the power goes to the light first. If it appears power should be coming to the switch first, a loose conection between there and the breaker panel.
     
  7. Feb 17, 2014 #7

    brewer79

    brewer79

    brewer79

    Junior Member

    Joined:
    Feb 17, 2014
    Messages:
    3
    Likes Received:
    0
    I don't believe power goes to the switch first, I know that the switch is on a circuit with a bunch of other outlets that don't have a problem.

    I did replace wire for wire on the switches but it still doesn't seem to work. That's when I took the switches out, left all the wiring out of the box and tested it to see what registered hot.
     
  8. Feb 17, 2014 #8

    nealtw

    nealtw

    nealtw

    Contractor retired

    Joined:
    Nov 4, 2010
    Messages:
    23,897
    Likes Received:
    3,117
    You will have to look in the light box for lose wires, if not there somewhere else that feed that, You could have a loose connection in an outlet box or light with a working outlet or light.

    The three way should have a three wire, red black and white,and ground. You will have to figure out if the three wire goes from one switch to the other or to the light and then to the other switch.
    Does the box with power have a two wire and a three wire? does the other box have a two wire and a three wire?
     
  9. Feb 18, 2014 #9

    Wuzzat?

    Wuzzat?

    Wuzzat?

    Well-Known Member Sponsor

    Joined:
    Jan 20, 2010
    Messages:
    2,471
    Likes Received:
    175
    Last edited: Feb 18, 2014
  10. Feb 18, 2014 #10

    nealtw

    nealtw

    nealtw

    Contractor retired

    Joined:
    Nov 4, 2010
    Messages:
    23,897
    Likes Received:
    3,117
    Wuzzat? likes this.
  11. Feb 18, 2014 #11

    havasu

    havasu

    havasu

    Guest

    I won't add anything but to say them things have always confused the hell out of me!
     
    nealtw likes this.
  12. Feb 18, 2014 #12

    bud16415

    bud16415

    bud16415

    Fixer Upper Staff Member Admin Moderator

    Joined:
    Feb 5, 2013
    Messages:
    4,657
    Likes Received:
    1,598

    I think you might have a high impedance meter and it’s leading you to reading all these phantom voltages. A good general purpose multi-meter with lower impedance should not be reading these. Most people doing home wiring will not be testing transistors and such.
     
  13. Feb 18, 2014 #13

    bud16415

    bud16415

    bud16415

    Fixer Upper Staff Member Admin Moderator

    Joined:
    Feb 5, 2013
    Messages:
    4,657
    Likes Received:
    1,598

    A 3way and 4way switch shouldn’t be confusing but for most people they need to see it in schematic form and then the light comes on for them. Pun intended. There are 100s of drawings on line that show pictures of switches and wire nuts and light bulbs. They are correct but they do confuse until you see what is inside the switch and how the terminals are arranged.

    A normal switch opens and closes a circuit. A 3way switch never opens the circuit it redirects it. Picture a water valve on the end of a hose and the normal switch stops the water. The 3way switch can never stop the water it has two openings for the water to come out A and B.

    It takes two of them working together to work and that is where seeing it in schematic form clears it up for most people. Wuz attached a google search link to his post and if you follow it shows page after of the wire nut pictures and a few with schematics. Here is one that shows it both ways.
    http://hometoys.com/emagazine.php?url=/htinews/dec97/articles/kingery/kingery6.htm
    No need to read past Fig 2. and it’s a good explanation up to that point on 3way control.

    Figure 2 on that page is as simple as it really is. The arrow is the switch SPDT (single pole double throw)The black and red are what they call the travelers and the white is the common wire.

    If you had two A/B valves and a sprinkler where the light bulb is you turn on the sprinkler from two different locations.
     
  14. Feb 18, 2014 #14

    Wuzzat?

    Wuzzat?

    Wuzzat?

    Well-Known Member Sponsor

    Joined:
    Jan 20, 2010
    Messages:
    2,471
    Likes Received:
    175
    A low input impedance meter, like 1000 ohms/volt (1 mA full scale reading for the meter movement) will give you very confusing readings.
    The low impedance meter needle stays on the same place on the scale because the current is constant no matter what range you're on, so you might see 50v on the 150v scale (0.3 mA) and then 17v on the 50v scale (0.3 mA) and then 5v on the 15v scale (0.3 mA).
    It's because the phantom voltage, 120v in series with thousands of ohms of capacitive reactance from the conductors being close together, acts like a current source rather than a voltage source. Readings like above confirm you are not measuring a voltage source.

    With a high impedance meter, the readings are more or less constant regardless of the range you're on, but slightly less than 120v.

    Wall outlets and batteries act like voltage sources while LED drivers and fluorescent ballasts act like current sources.



    BTW, if the wire colors in the OP's setup are not to code there is still a way to figure out where each one goes, either using an ohmmeter or
    an extension cord connected to a known good outlet and a test light or meter.
     
    Last edited: Feb 18, 2014
  15. Feb 18, 2014 #15

    bud16415

    bud16415

    bud16415

    Fixer Upper Staff Member Admin Moderator

    Joined:
    Feb 5, 2013
    Messages:
    4,657
    Likes Received:
    1,598
  16. Feb 18, 2014 #16

    Wuzzat?

    Wuzzat?

    Wuzzat?

    Well-Known Member Sponsor

    Joined:
    Jan 20, 2010
    Messages:
    2,471
    Likes Received:
    175
    The 10K meter Fluke talks about in the link would read about 2% of 120v, assuming you had 50' of two-wire-without-ground Romex.

    A cheapie meter on the 150v scale would have 150K of input resistance but the Wiggies had about 4K.

    Help Fluke go bankrupt by getting your 100W bulb with your existing meter! :D

    Fluke also makes a very expensive ground fault leakage current tester.
    You can do the same thing by getting a $15 GFCI, disconnecting the internal relay and picking a voltage off of the internal IC that is proportional to leakage current.
    With the schematic of the insides of the GFCI's IC (probably on the Web) this should be easy and there is at least one GFCI in my basement waiting on this surgery.
    Even if the GFCI no longer works the IC may still be good.

    One thing that is not easy for a DIYer is to duplicate one of their ground resistance testers.
     
    Last edited: Feb 18, 2014
  17. Feb 18, 2014 #17

    nealtw

    nealtw

    nealtw

    Contractor retired

    Joined:
    Nov 4, 2010
    Messages:
    23,897
    Likes Received:
    3,117
    Bud and Wuzzet: Nice; how about instructions on what to check and what you are looking for and what it will tell you after you have found it and what to do about it.
    I'm not sure what a test light will tell you that the ceiling light won't tell you. Likely all he has done is mix up two black wires or a black and white on the left side of one of the switches.
     
  18. Feb 18, 2014 #18

    bud16415

    bud16415

    bud16415

    Fixer Upper Staff Member Admin Moderator

    Joined:
    Feb 5, 2013
    Messages:
    4,657
    Likes Received:
    1,598
    That’s what I was trying to do in #13 the problem is without understanding how something works first and even havasu a long time poster admitted he is often confused by them. I posted in first again with a worry of advising someone to use a light bulb in a socket and two wires as a test device for voltage. There are a number of voltage testers for under 50 bucks some under 10 that are safer and do the same thing only better.

    To talk to the OP about wires is pointless unless he understands the concept first. I have seen 3ways wired up using 3 conductor wire red, black and white and I have seen them using 2 cables each with a black and a white. I have also worked on them with 3 knob and tube wires. If he had a working 3way and it stopped working and he changed each switch wire by wire as I think he claimed he should have been ok. But I believe Neal is correct he got something messed up along the way and now has to figure out what he has. Where he gets power and so forth. Before he does that IMO he should know how a 3way actually works in theory.

    I agree all this phantom voltage talk just muddies the water.
     
  19. Feb 18, 2014 #19

    nealtw

    nealtw

    nealtw

    Contractor retired

    Joined:
    Nov 4, 2010
    Messages:
    23,897
    Likes Received:
    3,117
    On re-reading the first post, this could be a loose wire nut at the light, or back to critters again.
     
  20. Feb 18, 2014 #20

    bud16415

    bud16415

    bud16415

    Fixer Upper Staff Member Admin Moderator

    Joined:
    Feb 5, 2013
    Messages:
    4,657
    Likes Received:
    1,598

    It could be anything.
     

Share This Page