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Goin' Down in Flames....
Highwayman
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Discussion Starter · #1 ·
I don't usually ask for advice here, but maybe I'm just overlooking an obvious solution, and someone has run into this before.

New construction, just installed lights. 1 circuit has 3 5-watt LED can lights, and 1 chandelier, containing 6 60-watt incandescent bulbs.

Any combination of 2 lights works fine, but as soon as all three are on, the 15 amp AFCI breaker trips.

I put an amp meter on each light individually, and on the breaker with every combination of 2 lights turned on, and never got more the 3.1 amps, which is exactly as it would calc out to be.

I'm going back over prolly next week, and start pulling stuff apart, but if anyone has any clues, I'd be glad to hear them.

Oh, and the fixtures are all HO supplied units from HD.

Thanks.
 

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I own stock in FotoMat!
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It's most likely an AFCI issue, not an overload issue.
 

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Goin' Down in Flames....
Highwayman
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6,482 Posts
Discussion Starter · #3 ·
That's what I was leaning towards.

I switched the load to different afci breaker, and it did the same thing, so now I just have to trace down the issue.

The strange part is why each unit is fine, but the issue only shows up when all three switches are on at the same time. I wonder what it is about all three being on at the same time that would cause some type of arc-fault. :confused:
 

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I own stock in FotoMat!
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Remove all the lamps (LED and incandescents) from all the lights and see if the AFCI trips.

If not, then the issue is with the lamps. If so, it's in the wiring.
 

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If it appears to be a function of all lights on....ie max current.... could it be a bad neutral splice??????

Just a WAG
 

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Goin' Down in Flames....
Highwayman
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Discussion Starter · #12 ·
Remove all the lamps (LED and incandescents) from all the lights and see if the AFCI trips.

If not, then the issue is with the lamps. If so, it's in the wiring.
What if there was an arc fault in the neutral?
 

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I really do not understand how arc faults work.... so this is sole conjecture and possibly rediculous thinking..... (I'm a DA GC)

But as this seems to be a higher current related issue,....

what if you pop a recep adapter in each light succesively as you move downstream, and plug in a heater (any high draw convenient appliance)...

and if it trips the arc fault, might that indicate/isolate an arc fault between the tripped location and upstream.....????


(For further questioning, if you had some impaired insulation (stripped off or nail intrusion in some romex) would the likelyhood of an arc fault be more likely (sensative) to current , or just voltage, or both????)

Just curious

Best
 

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Head Grunt
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3,270 Posts
Yes, that's what's in there.

But still, why only when all three switches are activated?
I would go through the diag like 480 mentioned but be mindful of the switch possibly being a problem. Try with and without the lights per switch to see if it is the lights, the wiring or the switch. Move the lights around or try a different load on each circuit to verify the problem. Have you checked the connection at the breaker itself? May be it takes a larger load to create enough resistance to trip the breaker. Is there stress on the wire at the breaker causing some stress to the breaker?
 

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Goin' Down in Flames....
Highwayman
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6,482 Posts
Discussion Starter · #17 ·
I would go through the diag like 480 mentioned but be mindful of the switch possibly being a problem. Try with and without the lights per switch to see if it is the lights, the wiring or the switch. Move the lights around or try a different load on each circuit to verify the problem. Have you checked the connection at the breaker itself? May be it takes a larger load to create enough resistance to trip the breaker. Is there stress on the wire at the breaker causing some stress to the breaker?
Thank you. Yes, I checked the connections at the breaker, and condition of wiring in general. All appears to be fine.

When I go back over there, I'll just start troubleshooting like for any issue, it's just that this one makes no sense to me.

The switch thing is interesting. Do you often have problems with snap switches on afci circuits? Do you have a favorite switch to use in those situations?
 

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Are they 120 V LED lamps or are they LV LED from a power supply? The switching power supply to the LED's could be a problem.

I would disconnect the LED's from the circuit first, nothing should happen when only the incandescents are connected unless there is a problem with wiring.

The AFCI detects high frequency signals on the circuit that would be produced if a low level arcing fault were present. False tripping can occur from signals generated by arcing motor brushes, low quality power supplies, or dimmers. Newer AFCI's are supposed to be more sophisticated and more resistant to false tripping.
 
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