Upright Mike
Member
- Location
- Lakes Region, NH
- Occupation
- Residential/Commercial EC
Hello all,
This week, I was working on a small residential remodel project in a fairly new house built within the last 8 years. While we were there, the homeowner asked us to look at some electrical issues he had been experiencing since the house was built. One of the problems had to do with a bedroom switched outlet. He showed me that every time he plugged a nightstand lamp into the receptacle outlet behind the nightstand, it would trip the breaker. We identified there was nothing wrong with the lamp itself because it worked fine when it was plugged into other receptacle outlets, and everything looked to be in safe and good working order. When another cord-connected piece of equipment was plugged into that receptacle, it would also trip the breaker instantly. This would happen regardless of whether the single pole switch controlling the switch conductor for the outlet was closed or open. I started by removing the devices in the switch box and inspecting the wiring. It was pretty straightforward: the box was being supplied by a 14/2 NM cable, and the black was pigtailed to supply the line side of the two switches in the box. The two other cable assemblies were 14/3; one was for the switched outlets, and the other was for a ceiling fan. The red conductor of the 14/3 assembly that was supplying the receptacle outlets was being used as the switched conductor. I traced out where that cable assembly went first and then proceeded to take that outlet box apart. In that box, there were two 14/3 NM cables, one from the switch box and the other went to the outlet box to the right of this one, there was also two 12/2 NM cables that were spliced together and on separate circuits of a different phase. The issue I found immediately was that instead of the 14-gauge conductors being connected to the receptacle outlet and being separated from the other circuit, the 14/3 that was supplying the outlet box to the right of it, the black conductor and the white neutral conductor were spliced together with the 12/2 conductors not the 14/2 two conductors coming from the switch box they were terminated on the device. The outlet box to the right, which was being supplied by the 14/3, which black and white conductors were spliced together with the 12/2 in the other box, was the last switched receptacle outlet. There were only two in the bedroom, one on each side of the bed. The only other cable assembly in the second box was a 14/2, which was supplying the next receptacle outlet on the wall to the right of that in the same bedroom. I separated the14/3 conductors from the 12/2 conductors in the first outlet box and remade them properly, like a normal switched outlet setup. The tabs were already broken on the hot side of the receptacle outlet; the red switched conductor terminated on the bottom, and the constant power black conductor terminated on the top. After I separated them and kept them on their appropriate circuits 14 to 14 and 12 to 12 everything functioned properly. That same lamp was connected to both sides of the receptacle and worked fine with out any tripping. I try not to cast shade towards other electrical contractors, but the whole electrical system was very poorly wired. We found a lot of bad connections and just sloppy work that had to be corrected. My question for the forum is, can anybody explain the theory of why this happened? Was the reason that caused the circuit breaker to trip when the black and the white of the 14/3 was connected to the 12/2 conductors of another circuit causing a phase to neutral short? Or was it because the current was trying to flow back on the opposing phase when the cord was connected it somehow completing the circuit? I believe this was not a phase-to-phase short because I think both circuit breakers would have tripped. Sorry for the lengthy question, I just wanted to give as much details as I could. I have found similar issues that others have posted on this forum, but my situation was a little different from what was posted. I want to thank everybody who has contributed to this forum. I greatly appreciate all the information that is shared here.
This week, I was working on a small residential remodel project in a fairly new house built within the last 8 years. While we were there, the homeowner asked us to look at some electrical issues he had been experiencing since the house was built. One of the problems had to do with a bedroom switched outlet. He showed me that every time he plugged a nightstand lamp into the receptacle outlet behind the nightstand, it would trip the breaker. We identified there was nothing wrong with the lamp itself because it worked fine when it was plugged into other receptacle outlets, and everything looked to be in safe and good working order. When another cord-connected piece of equipment was plugged into that receptacle, it would also trip the breaker instantly. This would happen regardless of whether the single pole switch controlling the switch conductor for the outlet was closed or open. I started by removing the devices in the switch box and inspecting the wiring. It was pretty straightforward: the box was being supplied by a 14/2 NM cable, and the black was pigtailed to supply the line side of the two switches in the box. The two other cable assemblies were 14/3; one was for the switched outlets, and the other was for a ceiling fan. The red conductor of the 14/3 assembly that was supplying the receptacle outlets was being used as the switched conductor. I traced out where that cable assembly went first and then proceeded to take that outlet box apart. In that box, there were two 14/3 NM cables, one from the switch box and the other went to the outlet box to the right of this one, there was also two 12/2 NM cables that were spliced together and on separate circuits of a different phase. The issue I found immediately was that instead of the 14-gauge conductors being connected to the receptacle outlet and being separated from the other circuit, the 14/3 that was supplying the outlet box to the right of it, the black conductor and the white neutral conductor were spliced together with the 12/2 conductors not the 14/2 two conductors coming from the switch box they were terminated on the device. The outlet box to the right, which was being supplied by the 14/3, which black and white conductors were spliced together with the 12/2 in the other box, was the last switched receptacle outlet. There were only two in the bedroom, one on each side of the bed. The only other cable assembly in the second box was a 14/2, which was supplying the next receptacle outlet on the wall to the right of that in the same bedroom. I separated the14/3 conductors from the 12/2 conductors in the first outlet box and remade them properly, like a normal switched outlet setup. The tabs were already broken on the hot side of the receptacle outlet; the red switched conductor terminated on the bottom, and the constant power black conductor terminated on the top. After I separated them and kept them on their appropriate circuits 14 to 14 and 12 to 12 everything functioned properly. That same lamp was connected to both sides of the receptacle and worked fine with out any tripping. I try not to cast shade towards other electrical contractors, but the whole electrical system was very poorly wired. We found a lot of bad connections and just sloppy work that had to be corrected. My question for the forum is, can anybody explain the theory of why this happened? Was the reason that caused the circuit breaker to trip when the black and the white of the 14/3 was connected to the 12/2 conductors of another circuit causing a phase to neutral short? Or was it because the current was trying to flow back on the opposing phase when the cord was connected it somehow completing the circuit? I believe this was not a phase-to-phase short because I think both circuit breakers would have tripped. Sorry for the lengthy question, I just wanted to give as much details as I could. I have found similar issues that others have posted on this forum, but my situation was a little different from what was posted. I want to thank everybody who has contributed to this forum. I greatly appreciate all the information that is shared here.
