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  • Microwave circuit breaker also pinned to trip another breaker

    It is bridged to the 20-amp breaker below. (Looks like that breaker is labeled "Kitchen GFI")

    Why connected?

    Can I snip the pin out, or must I remove a breaker?

    Thank you.
    I'd take an educated guess - but I'm unqualified.
    It ain't just soot, it's paydirt.
    "I swear, wherever Gift goes, argument follows." -Youtube comment

  • #2
    Re: Microwave circuit breaker also pinned to trip another breaker

    It's probably a 3wire circuit. Which means 2 hots and a common neutral. The handle tie is there because the two circuits share a neutral. Why are you wanting to remove the pin?

    Comment


    • #3
      Re: Microwave circuit breaker also pinned to trip another breaker

      Originally posted by Badabing View Post
      It's probably a 3wire circuit. Which means 2 hots and a common neutral. The handle tie is there because the two circuits share a neutral. Why are you wanting to remove the pin?
      To turn off only the microwave without affecting the other circuit.
      Just discovered three outlets on the other circuit. One on the wall each side of the microwave and one on the island across from the microwave.
      None appear to be on a GFI. (Or I simply have not found it.)

      The microwave outlet is 12-2 with ground.
      I'd take an educated guess - but I'm unqualified.
      It ain't just soot, it's paydirt.
      "I swear, wherever Gift goes, argument follows." -Youtube comment

      Comment


      • #4
        Re: Microwave circuit breaker also pinned to trip another breaker

        Originally posted by Robert Gift View Post
        To turn off only the microwave without affecting the other circuit.
        Just discovered three outlets on the other circuit. One on the wall each side of the microwave and one on the island across from the microwave.
        None appear to be on a GFI. (Or I simply have not found it.)

        The microwave outlet is 12-2 with ground.
        If you look in your panel do the two circuits that are tied together go to a single piece of Romex? It is likely that these two circuits are a "multiwire branch circuit", which basically means that if you turn off the breaker for the microwave, there could still be current flowing through the neutral of that circuit. The multiwire breakers must be common trip to prevent that.

        Comment


        • #5
          Re: Microwave circuit breaker also pinned to trip another breaker

          When you say the Microwave is 12/2 with ground, do you mean the wire that's at the plug for the microwave? Or what's coming out of the panel from that breaker? If it's at the plug for the micro, it could just be that a 3 wire circuit was run to 1 box (one of the plugs on the counter), then a 2 wire out to the microwave, very common when we wired houses. It's best to know what's on the breaker exactly, usually a black & red wire, for a 3 wire circuit.

          Comment


          • #6
            Re: Microwave circuit breaker also pinned to trip another breaker

            It's called a multiwire branch circuit and uses a two pole breaker or two single pole breakers connected together with a listed handle tie.
            This is compliant for the microwave and any wall receptacles. All receptacles near sinks on islands or countertops must be GFCI protected.
            If this MWBC feeds any counter tops there will be a GFCI receptacle supplying the remaining receptacles.
            Licensed Electrician

            Comment


            • #7
              Re: Microwave circuit breaker also pinned to trip another breaker

              Thank you, ALL!
              I will have to open the outside panel cover to see what was done.
              The duplex outlet inside the cabinet above the Spacesaver microwave is 12-2, Black,White,Green.
              Buthe wire also continues to somewherelse.

              Why this complication?
              I thought an overstove microwave was on its own dedicated circuit.
              Don't understand why its tied to the circuit breaker.
              Still have not found another GFCI for this circuit, whichas one outlet on the island and twoutlets on the wall either side of the stove.
              (Other outlets on the island and above counter are connected to a GFCI on a counter.)
              Last edited by Robert Gift; 03-20-2011, 11:33 PM.
              I'd take an educated guess - but I'm unqualified.
              It ain't just soot, it's paydirt.
              "I swear, wherever Gift goes, argument follows." -Youtube comment

              Comment


              • #8
                Re: Microwave circuit breaker also pinned to trip another breaker

                In reality it is NOT neccessary to have a tie between the 2 breakers on a 3 wire shared nuetral circuit. However in this case it may be that the tie is between the 2 breakers because the tab has been broken on the hot side of the outlet and one plug is fed from one circuit and one plug from the other circuit on the duplex. In a situation where this is the case and there are 2 different circuits on the same outlet then the breakers must be tied together. But in a simple 3 wire shared nuetral circuit the tie is not required, although not a bad idea. often ths is done in kitchens because 2 heavy draw items like a toaster and a microwave might want to be plugged in to the same outlet, so the tab is snipped and the 2 circuit connect to the same outlet. If I was you I would check and see if the tab is broken on the outlet and check to see if each plug of the duplex is on a seperate breaker.

                Comment


                • #9
                  Re: Microwave circuit breaker also pinned to trip another breaker

                  Thank you.
                  I just broke the tab in the microwave cabinet outlet to run a switched circuit to it. (The top receptacle now powers two under-cabinet puck lights. (Had to run the puck light zip cords up on each side of the microwave to a plug inside the cabinet). All the kitchen puck lights are controlled from a wall switch.
                  I understandistribting the loads. Still have not found GFI on the microwave's circuit.
                  I'd take an educated guess - but I'm unqualified.
                  It ain't just soot, it's paydirt.
                  "I swear, wherever Gift goes, argument follows." -Youtube comment

                  Comment


                  • #10
                    Re: Microwave circuit breaker also pinned to trip another breaker

                    Originally posted by QROKING View Post
                    In reality it is NOT neccessary to have a tie between the 2 breakers on a 3 wire shared nuetral circuit. However in this case it may be that the tie is between the 2 breakers because the tab has been broken on the hot side of the outlet and one plug is fed from one circuit and one plug from the other circuit on the duplex. In a situation where this is the case and there are 2 different circuits on the same outlet then the breakers must be tied together. But in a simple 3 wire shared nuetral circuit the tie is not required, although not a bad idea. often ths is done in kitchens because 2 heavy draw items like a toaster and a microwave might want to be plugged in to the same outlet, so the tab is snipped and the 2 circuit connect to the same outlet. If I was you I would check and see if the tab is broken on the outlet and check to see if each plug of the duplex is on a seperate breaker.
                    I am sure glad I returned to this thread, as this advice is WRONG.
                    The handle tie or double pole breaker IS required regardless of the receptacle tab or the two circuits going to completely different areas. ALL MWBC MUST be on a double pole breaker or two singles tied together with a LISTED handle tie.
                    Licensed Electrician

                    Comment


                    • #11
                      Re: Microwave circuit breaker also pinned to trip another breaker

                      Originally posted by John Valdes View Post
                      I am sure glad I returned to this thread, as this advice is WRONG.
                      The handle tie or double pole breaker IS required regardless of the receptacle tab or the two circuits going to completely different areas. ALL MWBC MUST be on a double pole breaker or two singles tied together with a LISTED handle tie.
                      Thank you for the warning.
                      MWBC?
                      (I can understand a listed tie.)
                      But why tied?
                      Why not two separate circuits - microwave circuit
                      and island-counter duplex outlets?
                      Are they somehow saving copper by omitting ONEutral wire?

                      To see if the microwave outlet is GFI protected, if I bridge Hot to Ground through a neon tester, will that conduct enough to trip the CFI?

                      Thank you.
                      I'd take an educated guess - but I'm unqualified.
                      It ain't just soot, it's paydirt.
                      "I swear, wherever Gift goes, argument follows." -Youtube comment

                      Comment


                      • #12
                        Re: Microwave circuit breaker also pinned to trip another breaker

                        Pardon me, the code has changed on that, At one time the tie was not needed, now it is, as I mentioned in my post I did say it was a good idea. I always thought it was a good idea and they finally changed the code on that. Since my parnter died prior to this code change haven't been doing much of this so that change has since passed me by. My apologies. Never really liked shared nuetral circuits myself but I worked for one guy who used them all the time to save time and money I suppose. I was an apprentice at the time and I really never liked the idea of the shared circuit, furthermore we never used ties on the breakers because it was not required then. I am actually happy they changed this.

                        Comment


                        • #13
                          Re: Microwave circuit breaker also pinned to trip another breaker

                          Originally posted by QROKING View Post
                          ...Never really liked shared nuetral circuits myself but I worked for one guy who used them all the time to save time and money I suppose....
                          Do they use a 12-3 cable: 2 hots, neutral and ground?
                          (Saves running another 12-2 with ground so saves 2 wires?)
                          I'd take an educated guess - but I'm unqualified.
                          It ain't just soot, it's paydirt.
                          "I swear, wherever Gift goes, argument follows." -Youtube comment

                          Comment


                          • #14
                            Re: Microwave circuit breaker also pinned to trip another breaker

                            a shared neutral will only work when the 2 poles/ hots are on opposite legs of the panel.

                            the neutral load will be the difference of the the load from the "a"and " b"side.

                            for example, "a" has a 10 amp load, and " has a 10 amp load. the neutral will have 0 amp load on it. but when one has 12 and the other has 3 then the difference is 9 amps on the neutral.

                            now if they were on the same leg of the panel the neutral would easily be overloaded by 2- 15 amp loads.

                            what is scary and dangerous is that if a neutral get loose or disconnected. the potential for 240 volts exist based on the draw from both legs on the shared neutral.

                            remember i'm a plumber, not a sparky so i might be slightly off

                            rick.
                            phoebe it is

                            Comment


                            • #15
                              Re: Microwave circuit breaker also pinned to trip another breaker

                              Originally posted by PLUMBER RICK View Post
                              ...what is scary and dangerous is that if a neutral get loose or disconnected. the potential for 240 volts exist based on the draw from both legs on the shared neutral. rick.
                              You are correct, which is anothereason I don't knowhy they would do this. Buthe chance of that happening is extremely remote.
                              I'd take an educated guess - but I'm unqualified.
                              It ain't just soot, it's paydirt.
                              "I swear, wherever Gift goes, argument follows." -Youtube comment

                              Comment

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