Announcement

Collapse
No announcement yet.

Backstabbing 15a receptacles and switches

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    #16
    Originally posted by ChargedUp View Post
    ...I'm not a licensed electrician. I went to home depot and bought the preferred receptacles by Leviton and wired them in my house. If we are talking about circuits larger than 15A with high load, then I would agree backstabbing may not be best practice. But for 15A receptacles with cell phone chargers, TVs, lamps etc, even a heater for that matter, pulling less than 12A, I do not see the issue with using the quick connect ports that the manufacturer provided and UL approved, nor inefficient energy transfer, etc with such small loads.

    ...

    Screw connections can loosen and fail as well if not installed properly. ...
    The underlined keeps getting brought up. Of course it's true. And the ratio is about 300:1 in the experiences of my wife and myself, both licensed electricians for twenty years each.

    Comment


      #17
      Originally posted by ChargedUp View Post
      Thanks for the responses. To M_J_C's last post, yes I understand the NEC is a minimum standards guide, not a design guide, and also the function of UL listing. I'm not a licensed electrician. I went to home depot and bought the preferred receptacles by Leviton and wired them in my house. If we are talking about circuits larger than 15A with high load, then I would agree backstabbing may not be best practice. But for 15A receptacles with cell phone chargers, TVs, lamps etc, even a heater for that matter, pulling less than 12A, I do not see the issue with using the quick connect ports that the manufacturer provided and UL approved, nor inefficient energy transfer, etc with such small loads.

      Yes, there is always going to be something better with everything in life, but for the amount of comments on the web stating that back-stabbed receptacles are less than adequate, doesn't seem to line up with manufacturer and UL.

      Screw connections can loosen and fail as well if not installed properly. Even if you pigtail around the screw, the connection can still loosen, and resistance can build up. And we also don't know what any given receptacle was exposed to in it's past life...was the faulty back-stabbed receptacle in question connected to a fully loaded surge protector with 6 devices on it, etc.

      Thanks again for the posts.
      UL does not in fact "Approve" anything. They list devices and assemblies in the Building Materials List if the item conforms to an industry standard for that item. UL does not write the standards. UL tests for compliance with a standard. All the listing asserts is that the item complies with a specific standard. There are undoubtedly thousands of items which were once listed in the Building Materials List which would not test successfully to presently accepted standards.

      Are you aware that the "Back Stab" receptacles are now only listed for #14 American Wire Gauge? The side mounted terminal screws, if provided, are listed for #12 AWG as well as #14. Initially the spring terminals were listed for both gauges. Since they had to be made with a hole large enough for the larger gauge, but were mostly used for #14 wire, they allowed #14 to move too much as it expanded and contracted from the regular cycling of various loads going on and off. The presently manufactured spring terminal receptacles will not pass the listing standard if the holes into the terminal are large enough to except #12 wire. The smaller hole forces the #14 conductors to remain in position under the contact spring. There is no longer any room for them to shift out of full contact. The spring configuration has also been altered to provide more contact area with the conductor. No conductor movement and a larger contact area equals adequate real world performance. The new ones are much better than the old dual gauge type but the truth is that until they have provided 20+ years of service without a significant number of failures I won't trust them so I won't use them.

      I am retired out of both the electrical craft and fire and rescue service. With 5Ø+ years of electrical installation experience on 3 continents I have seen how the earlier versions of several devices did not stand the test of time. Towards the end of my active electrical work I avoided early adoption of new technology as if it were bubonic plague. I never regretted not being a test technician for the latest and allegedly greatest speedier to install device or luminaire.

      --
      Tom Horne
      Tom Horne

      "This alternating current stuff is just a fad. It is much too dangerous for general use." Thomas Alva Edison

      Comment


        #18
        Originally posted by cpickett View Post

        In industrial applications when you're talking about a large motor that runs 24/7, sure, but in a residential application would the savings (if any) amount to anything?
        The POCO metering device generally uses CT's at the service entrance point to measure how much $$ is passing through, the greater the voltage drop at the point of use, the more current the device uses (generally, but not always) to achieve its rated output. Ever notice a motor that has a two amperage ratings, one for 230V and and one for 208V? The same is true for most loads, as voltage drops, current goes up, not to mention incidental heating of the structure, something we don't need in the south!. Here are some references:
        https://www.ecmweb.com/electrical-te...conductor-size
        https://www.copper.org/environment/s...onesizeup.html
        https://www.energy.gov/sites/prod/fi...tip_sheet8.pdf
        https://iaeimagazine.org/magazine/20...-voltage-drop/

        Comment


          #19
          Originally posted by hornetd View Post
          ... Initially the spring terminals were listed for both gauges. Since they had to be made with a hole large enough for the larger gauge, but were mostly used for #14 wire, they allowed #14 to move too much as it expanded and contracted from the regular cycling of various loads going on and off. The presently manufactured spring terminal receptacles will not pass the listing standard if the holes into the terminal are large enough to except #12 wire. The smaller hole forces the #14 conductors to remain in position under the contact spring. There is no longer any room for them to shift out of full contact. The spring configuration has also been altered to provide more contact area with the conductor. No conductor movement and a larger contact area equals adequate real world performance. The new ones are much better than the old dual gauge type ...
          Thank you very much for this. I will start looking for the difference when I see these from now on. I did notice that receptacles I buy would only accept #14 in the stabs, but I hadn't noticed what the old ones were like.

          Comment


            #20
            Originally posted by M_J_C View Post

            The POCO metering device generally uses CT's at the service entrance point to measure how much $$ is passing through, the greater the voltage drop at the point of use, the more current the device uses (generally, but not always) to achieve its rated output. Ever notice a motor that has a two amperage ratings, one for 230V and and one for 208V? The same is true for most loads, as voltage drops, current goes up, not to mention incidental heating of the structure, something we don't need in the south!. Here are some references:
            https://www.ecmweb.com/electrical-te...conductor-size
            https://www.copper.org/environment/s...onesizeup.html
            https://www.energy.gov/sites/prod/fi...tip_sheet8.pdf
            https://iaeimagazine.org/magazine/20...-voltage-drop/
            That’s some funky math on some of those articles... not enough information to achieve some of their results.
            It makes sense the copper industry says to upsize the wire. Their figures are with a 15 amp load running continuously. Plus everything else in the house... you can afford that, $17 more ain’t gonna hurt you...

            Comment


              #21
              Originally posted by M_J_C View Post

              The POCO metering device generally uses CT's at the service entrance point to measure how much $$ is passing through, the greater the voltage drop at the point of use, the more current the device uses (generally, but not always) to achieve its rated output. Ever notice a motor that has a two amperage ratings, one for 230V and and one for 208V? The same is true for most loads, as voltage drops, current goes up, not to mention incidental heating of the structure, something we don't need in the south!.
              I must disagree with that generalization. Motors do indeed attempt to be constant-power loads and behave as you described (current varies inversely with voltage), but the vast majority of residential loads tend to be constant-impedance loads (current varies proportionately with voltage).

              With incandescent bulbs, for one example, if the voltage sags, so does the current. Only if a larger bulb is substituted would the user cause an increase in $$ as a result. With electric heat, the heat will run cooler, but will need to run longer in compensation to keep the thermostat satisfied.
              Master Electrician
              Electrical Contractor
              Richmond, VA

              Comment


                #22
                Originally posted by ChargedUp View Post
                Thanks for the responses. To M_J_C's last post, yes I understand the NEC is a minimum standards guide, not a design guide, and also the function of UL listing. I'm not a licensed electrician. I went to home depot and bought the preferred receptacles by Leviton and wired them in my house. If we are talking about circuits larger than 15A with high load, then I would agree backstabbing may not be best practice. But for 15A receptacles with cell phone chargers, TVs, lamps etc, even a heater for that matter, pulling less than 12A, I do not see the issue with using the quick connect ports that the manufacturer provided and UL approved, nor inefficient energy transfer, etc with such small loads.

                Yes, there is always going to be something better with everything in life, but for the amount of comments on the web stating that back-stabbed receptacles are less than adequate, doesn't seem to line up with manufacturer and UL.

                Screw connections can loosen and fail as well if not installed properly. Even if you pigtail around the screw, the connection can still loosen, and resistance can build up. And we also don't know what any given receptacle was exposed to in it's past life...was the faulty backstabbed receptacle in question connected to a fully loaded surge protector with 6 devices on it, etc.

                Thanks again for the posts.
                Heater is exactly the kind of load that runs for long enough periods that heating effects in any poor connection last for long enough cycles that the connection begins to degrade much quicker than for lighter loads or even heavy loads that never have much duration. Doesn't matter if it is a backstab connection, screw terminal, plug to connector pressure, etc.

                I live for today, I'm just a day behind.

                Comment


                  #23
                  Originally posted by M_J_C View Post

                  The POCO metering device generally uses CT's at the service entrance point to measure how much $$ is passing through, the greater the voltage drop at the point of use, the more current the device uses (generally, but not always) to achieve its rated output. Ever notice a motor that has a two amperage ratings, one for 230V and and one for 208V? The same is true for most loads, as voltage drops, current goes up, not to mention incidental heating of the structure, something we don't need in the south!. Here are some references:
                  https://www.ecmweb.com/electrical-te...conductor-size
                  https://www.copper.org/environment/s...onesizeup.html
                  https://www.energy.gov/sites/prod/fi...tip_sheet8.pdf
                  https://iaeimagazine.org/magazine/20...-voltage-drop/
                  Ever multiplied the amps by their respective volts - you still get same volt-amps, which after you consider power factor is going to give you watts - you are billed for energy used as watt-hours.

                  Where increase in wire size for VD gives you any savings is because of lost watts in the circuit conductors. But what was earlier mentioned means a large industrial motor with significant VD losses on the conductors is going to lose many more watts over a 24/7 time frame than some item that has losses on lesser scale and especially if it doesn't get same run time.

                  Yes heat lost into the structure is also creating more energy demand because now the cooling system needs to remove that heat. Depending on the load served this may not matter much though. If it is a heat producing load you are adding heat to the structure anyway. If you make toast in the morning in your kitchen, heat from both the toaster and any heat lost in the circuit to your toaster are both still lost to the inside of your house and the cooing system needs to remove that heat, but there is a huge difference in amount of heat from making that couple slices of toast vs having same wattage of space heater running inside the house all day long.
                  I live for today, I'm just a day behind.

                  Comment


                    #24
                    Originally posted by LarryFine View Post
                    I must disagree with that generalization. Motors do indeed attempt to be constant-power loads and behave as you described (current varies inversely with voltage), but the vast majority of residential loads tend to be constant-impedance loads (current varies proportionately with voltage).

                    With incandescent bulbs, for one example, if the voltage sags, so does the current. Only if a larger bulb is substituted would the user cause an increase in $$ as a result. With electric heat, the heat will run cooler, but will need to run longer in compensation to keep the thermostat satisfied.
                    With electric heat as long as line losses occur inside the area to be heated you didn't lose anything for operation costs.

                    I live for today, I'm just a day behind.

                    Comment

                    Working...
                    X