Outlet Connections

Discussion in 'Electrical Forum discussion & Blog' started by coopns, Aug 19, 2013.

  1. coopns

    coopns New Member

    Messages:
    95
    Location:
    Massachusetts
    I am replacing an older outlet. I have two black, two white and a red. They had 2 white and 2 black around the screws then inserted the red in the back (through the small hole directly in the back of outlet). My new outlet doesn't except the red. Could I piggy the two blacks together then the red would go on a screw?

    Please advise.

    Thanks.

    **Update**
    I tried the two blacks with a pig tail, that worked. So I have whites on one side, pig tailed the blacks to bottom screw and red to top. Seems to work but would like someone to let me know.
    Last edited: Aug 19, 2013
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,268
    Location:
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    It's almost never acceptable to put two wires underneath one screw on a receptacle, but, tying them together first and using a pigtail to do it is fine IF you use the right wire. Many receptacles have holes in the back that can take up to two wires and are clamped by the screw. WIth those, it is acceptable to use both the screw and the holes which would give you three or as many as six connections. I will stay that it is important that the wire gauge be identical when using two wires in the back...the clamping plate on at least some does not swivel, and getting it tight to two diverse sizes may not happen!

    Now, if you still have the old receptacle available, take a look and see if the tab between the two hots was broken. IF it was, then you have NOT wired it properly. A red wire is typically the identifier of a switched power lead, and it may have been used to switch one half of the receptacle for something like a table lamp. By tying all of the leads together, that switch no longer can function, and, if the power happened to be on the other leg, bad things would happen when the switch was turned on.
  3. coopns

    coopns New Member

    Messages:
    95
    Location:
    Massachusetts
    I do have the old and the tab is broken.

    So I got it wired wrong.

    I have those two blacks together then pig tailed out to one screw and the red to the top. Wrong?

    Thanks.
  4. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    Not wrong. Although I always set the switched half of the receptacle on the bottom, because I assume the lamp will always be plugged in, and possibly the top outlet will be used for things that come and go, vacuum cleaners in particular.

    It is a very small point of detail.

    Do, however, ensure that your white wire is going to the wider slot, which will have silver screws, and that your black or red wires go to the narrow slot, with the brass screws.

    Jad has a good point: better outlets have a plate on the side, actually two, each pressed down by a screw.

    On THESE you can insert two wires, so your two black wires can go under one plate and be held down by the one screw, which will save you some space in the box. Often that is worth doing.

    Also, rarely, the red wire is at the opposite end of the sine wave from the black wires, and shares the neutral for a return. That makes it a "three wire circuit". Which means that one can no longer use the receptacle for a junction of the white wires, they must be pig tailed together.

    Further information at wikipedia, I think. "Three wire circuit". Two hots sharing a neutral. If this confuses you you probably want to hire someone to check it out.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
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    Location:
    Cave Creek, Arizona
    quote; rarely, the red wire is at the opposite end of the sine wave from the black wires, and shares the neutral for a return. That makes it a "three wire circuit". Which means that one can no longer use the receptacle for a junction of the white wires, they must be pig tailed together.

    I have no idea what this means, nor have i ever seen it done. If I read it correctly, the receptacle would not have a neutral connection. "Two hots sharing a neutral" only works if they are on opposite legs of the 240 circuit, otherwise the neutral can be overloaded.
  6. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,560
    Location:
    North Carolina
    he says he had the blacks and red connected to the receptacle so they are not on two legs or the thing would have tripped
  7. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    "Opposite legs of the 240 circuit" = "opposite ends of the sine wave.

    The neutral is drawn down the middle of the sine wave.

    So no, you do not read it correctly.

    And I did write that it was very rare. However, I came across it in Burbank just a few months back.
  8. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA

    Fair point.
  9. coopns

    coopns New Member

    Messages:
    95
    Location:
    Massachusetts
    Sorry to recap (please correct me/excuse me)

    2 whites - one to each screw
    2 blacks - tied them together, pig tailed out to bottom brass
    1 red - on top brass

    The tab was broken on the old recptacle. Does it have to be? It is behind a bed, wouldn't be used by switch.

    And...I have a multimeter, just a cheap one but don't know how to use it. Just a cheap harbor freight one. What settings should it be set to, could someone give me a primer?

    Thanks for the advice.
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,268
    Location:
    New England
    Okay, if the tab was broken, that means each half of the receptacle was powered by different circuits...so yes, you should break the tab. Then, check out any switches in the room. Put the red wire on one of the hot sides, and pigtail the two blacks to the other on the other. The black part should be hot all of the time, the red side should turn on and off with a switch somewhere. Then, plug something into the side that has the red wire feeding it. See if it will turn on. If it does, go around to any switches in the area, and flip them off and see if it goes off with the switch. If it does not come on, then flip switches until it does come on.
  11. jwelectric

    jwelectric Electrical Contractor/Instructor

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    Location:
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    No but if you are not planning on using the switched part then if it were me I would remove it from the receptacle and place a wire nut on it so that it wouldn't be back feeding the switch as at some latter point cause someone to get hurt.
  12. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    The tab was broken on the old recptacle. Does it have to be? It is behind a bed, wouldn't be used by switch.

    [/QUOTE]

    Code requires that each room have a light or outlet that can be controlled from the door as a person enters.

    The concept with your room was that a light(s) at the bed would come on and off by a switch at the door.

    Unless there is a light in the center of the ceiling...
  13. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,560
    Location:
    North Carolina
    True code requires a wall controlled lighting outlet in every habitable room but nowhere in the code does it require the switch to be beside the door.
    It would be a code compliant installation to put every light switch beside the panel and no switch in any room. It would be also code compliant should the breaker be marked “SWD” and no switch be installed anywhere.
  14. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,049
    Location:
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    quote; The neutral is drawn down the middle of the sine wave.

    In that case the duplex has each receptacle fed by a different leg of the 240 circuit, and the neutrals CAN be joined at the receptacle, they do not have to be pigtailed together. It is also not "rare", in fact I wired most of the duplexs in my previous residence that way so a tripped breaker did not disable both openings.
  15. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    I cannot POSSIBLY imagine a planning dept approving a home plan that showed no switches for lighting at the entrances to rooms.

    Likewise I cannot POSSIBLY imagine an inspector who would go for it.

    Possibly one could read the code so closely that in a very pedantic manner what you write would be true, but the actual INTENT of the code is pretty clear to me: that the ability to turn on some light source from the door is required.
  16. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    You are missing a stern requirement of current code: that where a neutral is present in a three wire circuit, it cannot be joined at a receptacle, such that removing the receptacle could CONCEIVABLY interrupt the neutral and cause the two legs to vere off of 120 v. I don't actually know how many years ago this came into the code, ask JW. But this means that in such a case, pig tails are required.

    A very recent addition to the code is that when two branch circuits share a neutral, they must either be wired to a two pole breaker or the breakers must be adjacent and fitted with rated handle ties. So when I do a repanel these days, I just use two pole breakers. And so your solution to losing power with a tripped breaker drops away. You would need to have four wires.

    I don't know what we are going to do when Arc Fault breakers become required in any panel retrofit. Charge the customer for it and try to explain the safety advantages, I suppose.

    I am looking over a large-ish job (by my standards, being a one-man band) tomorrow. I expect the customer to want to replace all the old rubber/cloth wire. And the city will insist on Arc Vault breakers. I WON'T be attempting to wire them with a common neutral!
  17. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,560
    Location:
    North Carolina
    Intent cannot be enforced but the letter of the code is enforced. Planning departments and inspectors could care less where the switch is located all they are interested in is compliance.

    Every day breakers are used as switches in commercial and industrial applications.

    I have a room that is 16 feet wide and 36 feet long that has two ceiling fans with lights that has no switches anywhere in that room. Such as in this picture

    Attached Files:

  18. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,560
    Location:
    North Carolina
    The reason we pigtail the neutral in a multiwire branch circuit is due to the shock hazard of the current carrying of the neutral. The reason it is required and, always has been when the circuit landed on a single device like a duplex receptacle, to be on a two pole breaker is due to the loss of the neutral would result in a 240 volt circuit.

    If the original poster had connected the red and black to the receptacle of a multiwire circuit without removing the fin tab it would have tripped the breaker with or without the neutral being connected to anything.

    The fact that he was able to tells us that the switch is supplied by the same circuit as the receptacle.
  19. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,268
    Location:
    New England
    Not if the switch was never turned on...
  20. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    Ah. Crazy me, I was speaking of residential requirements, and not commercial or industrial. Indeed it is permissible to shut off a "branch circuit" with only the breaker and no other device in commercial and industrial applications. I am FAIRLY confident that the OP was writing of a residential application, yes?

    As for "Planning departments and inspectors could care less where the switch is located all they are interested in is compliance." I can only say we know different inspectors. If there are no switches at the entrance for that bedroom you described, I can only say woopdie do. You out-smarted the local authorities.

    The code DEMANDS that a three way switch be fitted at the top and bottom of a stairway in a house, and that it control a light that will illuminate the stairs sufficiently that most people will be able to get up and down those stairs safely. And breakers ain't got not'in to do with it.
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