Siemens Arc Fault/GFCI breaker intermittent trip

[RRonke]

Customer wanted me to find why their living room circuit keeps turning off unpredictably and showing arc fault on the living room Siemens breaker.
1st service call: During this call the breaker never tripped . They said it started tripping sometime after they got a QLED tv last year but breaker tripped with tv off.
1. disconnected line, line neutral, and grounding wires from living room breaker and checked continuity line to grounding, neutral to grounding, and line to neutral after unplugging all living room cords and turning off switches. no continuity seen
2. unscrewed both 3 way switches, pulled them away from wall and while light was on I rapped on all sides with screwdriver handle. light stayed on
3. Took apart all receptacles and switches, and the push-in connections for any movement. All were tight. Also checked grounding wires too close to neutral post.
4, switched the living room breaker with another breaker that had never tripped (these are not PON breakers)
5. They had a chandelier type ceiling light with five 60 watt Halogen with the five supports for the element that I started to check but the husband sent me on my way because he figured we fixed it when we swapped breakers.
They called next morning. It had tripped 4 times with only the light on.
2nd service call: I did get to see the arc fault trip this time.
1. removed chandelier ceiling fixture and found the fixture wires had been pinched before and were taped up and arc marks on support bar.
2. cut back wires to get rid of pinched areas
3. removed bulbs, checked arc marks on bulbs. found none
4. checked shells for loose rivets and carbon tracking. No carbon tracking but two loose shells. marked those to not put bulbs in for testing
5. checked all sockets for any center contact arc marks. found none. checked bulbs for loose supports and broken elements
6. megged line and neutral light fixture wires to grounding wire and line to neutral and got infinite readings
7. disconnected travelers and megged. Got high resistance reading.
8. remounted ceiling fixture and shook it with the light on. The light stayed on.
9. cycled switches alternating back and forth and finally tripped arc fault
10. Found if one P&S switch was moved sideways a bit I could trip arc fault.replaced P&S with Leviton 3 way
11. moved the toggle up and down and sideways on new switch and other switch and could not create arc fault
I said I would drive away slowly while they tried to create arc fault. I made it home!
Next morning the dreaded call. the arc fault breaker had tripped 4 times by them turning the switches on and off and they left out the two bulbs with loose shells
Asked about mice in attic potentially chewing insulation because I have fought that battle. None to their knowledge.
Any other troubleshooting ideas?
Not looking forward to an attic adventure if I can avoid it.
Thanks for any ideas.

 

[hbiss]

They said it started tripping sometime after they got a QLED tv last year but breaker tripped with tv off.

The obvious thing to suspect is the TV. And, they are never off even if turned off. Did you leave it unplugged for any length of time? How about connecting it with an extension cord from another circuit?

Other than that, I think you are chasing your tail with all what you did. Just get rid of the AFCI breaker.

-Hal

 

[Jraef]

How old is the breaker? Siemens (and all of the other early adopters) has “updated” their AFCI breakers several times over the years due to nuisance tripping. At first it was from appliances that had brushed motors, but then again because some types of non-linear loads, like electronic power supplies, were drawing current in what the algorithm was misinterpreting as an arc signature. I have recently had to swap out one that was only a little over 5 years old because of this. The new one held.

 

[don_resqcapt19]

How old is the breaker? Siemens (and all of the other early adopters) has “updated” their AFCI breakers several times over the years due to nuisance tripping. At first it was from appliances that had brushed motors, but then again because some types of non-linear loads, like electronic power supplies, were drawing current in what the algorithm was misinterpreting as an arc signature. I have recently had to swap out one that was only a little over 5 years old because of this. The new one held.

Just points out the problem with this...the NEC and the manufacturers want us to believe that the AFCIs know ever normal arc signature of every piece of equipment that is currently in existence along with every piece of equipment that will come into existence within the life of the AFCI...absolutely impossible.