AFCI/GFCI tripped with LED light

Discussion in 'Electrical Forum discussion & Blog' started by Sunadmn, Dec 4, 2019.

  1. Sunadmn

    Sunadmn New Member

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    Austin Texas
    Howdy all!

    I have a very odd electrical issue that has me stumped. I recently had my sub panel updated and when we did that we brought everything up to code by adding combo AFCI/GFCI breakers. I have a branch circuit that runs the outlets in my three bathrooms, tow exterior outlets, and a closet light.

    I had issues with it tripping and the company that did the panel upgrade just put in a normal break, they didn’t troubleshoot. This bothered me so I decided to take on the finding of the issue. I traced the circuit down and tested each leg. I found a wire buried in a wall from a previous owner that was duct taped over. Pulled tape off and they ran a nail through the Romex and just put tape on it and put Sheetrock over it, sigh.......

    I corrected this and just cleaned up the circuit with new Romex where needed. During this I added a HD Hampton bay LED light in the closet and a Leviton 5691 paddle switch. Everything works fine and each outlet test fine with my circuit tester, however once I flip the rocker to energize the light the breaker trips instantly (I put a 20amp AFCI/GFCI in place of the standard breaker). If I disconnect the light from the switch and flip it everything is fine. I am lost as to what could be happening here does anyone have any ideas on WTH could be going on?

    Cheers,
    -Stephen
     
  2. Reach4

    Reach4 Well-Known Member

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    That is a lot to put on one circuit.

    So its the GFCI outlet that is tripping. How about a diagram of the circuit that is connected to the load terminals on that GFCI outlet. You can use a pencil and paper, and scan or photograph that. Make that a jpg file. Or you could draw using a paint program and maybe save it as a gif or png file.
     
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  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Well, that layout wouldn't meet today's codes, but hey, grandfather helps here. The light fixture itself might be defective. Also, make sure that it's not wired up backwards. Double-check that there are no loose wires, or excessively stripped ones that might touch some other bits they're not supposed to.

    I had one issue where a branch with a GFCI would trip intermittently. I eventually traced it down to one wire run. Given where it went, I decided to just rewire that last receptacle to a new circuit, and things have been stable. THere MIGHT be another nail or pinch in a cable that you have not found yet. If the cable has a clamp going into the box, make sure it has not damaged the insulation. A staple could be too tight, or lots of other possibilities. The ambient temperature can make a difference, too, as things slightly expand and contract with temperatures making it hard to locate.
     
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  5. WorthFlorida

    WorthFlorida The wife is still training me.

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    Is it an overload, the GFCI or the AFCI that is causing the tripping? Each are completely difference causes. Did it trip before replacing the standard breaker with the new LED fixture? Does this circuit has 12 gauge wire? (12 AWG=20 ap, 14 AWG=15 amp). After performing what Jim suggest, it could be a bad fixture. LED lights have a built in driver (power supply) and this part will usually fail before the LED itself does.
     
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  6. Sunadmn

    Sunadmn New Member

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    Attached is a diagram.

    I have inspected the whole run, and thus why I replaced certain parts of the run. I also thought hey bad fixture so I installed a new one and both do the same thing. I didn't test the run with a standard breaker after I fixed the short, but I can do that.

    Yes, this is all 12AWG, and there is no load anywhere on the circuit when this happens. I wanted to be sure nothing else could be the culprit so I yanked everything off and instructed the wife to not plug ANYTHING in.
     

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  7. mliu

    mliu Active Member

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    AFCI's are notorious for false tripping. They work by looking for electrical noise on the wire that might be caused by arcing. The problem is that many appliances and fixtures create noise that cause false trips. Vacuum cleaners were a very common cause of false trips when AFCIs were first mandated. I suspect the LED driver in that light fixture is back-feeding some noise into the line. I bet if you replaced that lamp with a straight incandescent bulb, it would work fine.

    You haven't told us what the make & model of AFCI/GFCI breaker was installed. Some are more prone to problems than others. Also, the breaker should have a way of indicating what caused it to trip (overload, ground fault, or arc fault).
     
  8. Reach4

    Reach4 Well-Known Member

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    I think you could have used an AFCI breaker, and several GFI outlets. That would have some advantages for both troubleshooting and for not having things go dark if a gfi trips.

    img_3.png

    So I am thinking to maybe open the wires at 4, both hot and neutral. See if the breaker trips. That will split the circuit up. Then if no trip occurs, restore 4, and open 6 or 9. And so on.

    Or maybe start with 6 or 9 if the LED fixture is the lead suspect.

    Also, it is possible that opening the hots will be sufficient for troubleshooting. That should certainly stop the LED driver from generating noise.
     
  9. mliu

    mliu Active Member

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    I would replace the AFCI/GFCI Frankenbreaker with a regular breaker and install GFCI outlets in the three bathrooms and two exterior outlets.
     
  10. Sunadmn

    Sunadmn New Member

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    Ahh yes sorry i should have mentioned the breaker type.

    Eaton Type CH Plug on Neutral CHFCAF120PN 20 AMP
     
  11. Sunadmn

    Sunadmn New Member

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    So I pulled everything off one by one when I was tracking down the initial fault and everything is fine up to the 6-9 leg. and even when 11 is not connected (wire nut only) everything is fine. I think we might be onto something with the AFCI being sensitive to the noise. I am going to test with the standard breaker in a bit and will report back.
     
  12. WorthFlorida

    WorthFlorida The wife is still training me.

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    The part number you typed in doesn't have GF protection. Is it a typo? Find the installation guide and check if yours do have stored trip codes!

    From Eatons website.

    CHFAFGF120PN - Type CH 3/4" Afci/Gfci W/Flag, 1P, 20A, 120V, 10ka
    Core features

    • AFCI
      • Advanced electronics to reduce unwanted tripping from non-compliant devices.
      • Standard LED indicates one of seven trip codes to simplify circuit diagnostics.
      • Trip codes are stored permanently into the breaker’s memory, to help identify “trip” history.
      • Branch overvoltage protection for sensitive electronics.
      • Meets areas requiring AFCI protection under the 200 and all subsequent edition of the NEC.
    • GFCI
      • One pole breakers 15–30A
      • 5mA protection per UL943
    • Plug-on neutral
      • Time savings up to 25% per AFCI and GFCI installation
      • Improved wireway access
      • Easier troubleshooting due to less wiring
      • Eliminates unwanted tripping due to loose pigtail connections
    • Limited lifetime warranty on all CH products
    If it is an arc fault trip, that is serious because you still have something that is bad as you did find some issues already. With nothing plugged in there is no current draw unless there is short or an arc occuring. At each outlet of the run I would replace all outlets since they are usually daisy chained to the next. After they are all connected and the LED fixture is off, get a drop light and plug it in at each outlet to see what happens. If no trip, then turn on the LED fixture and see what happens. The AFCI noise issue is something like a vacuum cleaner or other motor plugged into the circuit. LED drivers are all solid state but might have a small transformer. Early versions of AFCI (more than 10 years ago) were sensitive the would have false tripping but lately they are very stable.
     
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  13. mliu

    mliu Active Member

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    Solid-state circuits can generate quite a bit of line noise, particularly switching power supplies which are commonly used in devices like personal computers, consumer electronics, and LED light fixtures. Have you ever seen those things on electronic power cords that look like a dark gray ceramic donut or barrel (sometimes encased in plastic)? Those are ferrite cores and their purpose is to help block the back-feeding of noise from electronic circuits back into the AC line wiring.

    Despite improvements to AFCIs, they are still susceptible to false trips from such noise.

    Here is a related Q&A with Eaton engineers addressing this type of issue (red highlighting by me):

    4) I've noticed a lot of problems with mixed loads. Led and fluorescent on the same circuit. I've had a lot of problems with the tripping when led lights are on same circuit as an incandescent light and especially with a ceiling fan. What gives?

    [Eaton]: We believe the real issue is the conducted emissions (noise) being generated by the LED’s electronic switching power supply more so than mixed loads. Some LED’s are found to be exceeding the conducted emissions limits set by the FCC. This noise looks very similar to a series arcing condition and if all conditions are met, the breaker may trip. The breaker also need to have a minimum amperage of current flowing through it at the same time it recognizes the noise in order for its arc protection to kick in (varies by manufacturer) which is probably why you see more issues when using other loads along with the LED’s on the same circuit. LED does not draw much current so the noise itself does not trip the breaker until you add more load such as the incandescent bulb as you described.​
     
  14. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    FWIW, you can buy ferrite rings and try installing a pair on the hot/neutral of the light fixture...they're not expensive. MIght help, might not, but not a lot of money.
     
  15. WorthFlorida

    WorthFlorida The wife is still training me.

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    Good info Mlin.
    My first experience with an LED bulb was I installed two of them in my Chamberlain manufactured garage door opener. While the bulbs were on, the remote would not work until the leds turned off. I found on line from Chamberlain that they had a list a approved LED bulbs. Apparently the ones I had were putting out too much RFI.
     
  16. Sunadmn

    Sunadmn New Member

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    Well looks like I found the issue, buried in a wall in one run that tested fine with a circuit tester. I do think you all for the help and advise, next time I’m just gonna go with it’s lol bad replace everything.
     

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  17. HudsonDIY

    HudsonDIY Member

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    Looks a lot like a critter has been gnawing on it. Might want to check that out, they can do a lot of damage unchecked.
     
  18. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    A number of years ago now, when in the spring, I attempted to turn on my central air, nothing happened. Troubleshot it, and found a dessicated mouse that had part of his insides blown out that had walked across the power contactor. The guts had 'glued' the relay in position. At least, in this instance, he wasn't around doing further damage to other things!

    Sometimes, it takes a close visual inspection.

    FWIW, there are tools that would have detected a bad cable insulation like that, but being a specialized tool, and often, not all that inexpensive, not in most people's arsenal. That tool applies a high voltage to the wire and looks for any arcing or drop in the signal level, similar to what the AFCI must have detected. In the case of that test tool, it's checking the integrity of the insulation.

    Under the right conditions, that insulation defect could have started a fire, so it shutting down the circuit just shows, it was doing its job. People like to blame the devices, but most of the time, they're doing what they're supposed to do. When they trip, there's usually a good reason that should not be ignored.
     
  19. WorthFlorida

    WorthFlorida The wife is still training me.

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    Proves that AFCI and GFCI are well worth it. A fire could have started in the middle of the night. Real problem is how are critters getting inside the the home and walls.
     
  20. molo

    molo Member

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    -Good case for armored cable to prevent the rodent chewing. Yes it greatly increases the initial cost of a project but mice aren't chewing through it.
    -Interesting response from Eaton regarding the AFCI requiring a minimum amperage, does this mean they don't work if there is an arc fault condition and a low amperage LED is the only thing running on the circuit? From Eaton: "The breaker also need to have a minimum amperage of current flowing through it at the same time it recognizes the noise in order for its arc protection to kick in"
     
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