AFCI saying arcfault to ground

[Ravenvalor]

Hi Folks,
I've got a customer with a 9 - year old 15Amp Siemens circuit breaker that is constantly tripping. I put a new one in and it is tripping with the LEDs reading arc fault to ground. Can someone please give me some suggestions as to what I should be looking for?
Thanks,

 

[ptonsparky]

Check it as you would any circuit. Use a meter and isolate the portions of the circuit one at a until the fault is no longer there. This could be as simple as a. Continuity check between hot and the equipment ground up to megging the circuit. Find someone with experience and watch or assist if you can.

 

[Ravenvalor]

Check it as you would any circuit. Use a meter and isolate the portions of the circuit one at a until the fault is no longer there. This could be as simple as a. Continuity check between hot and the equipment ground up to megging the circuit. Find someone with experience and watch or assist if you can.

I failed to mention that the breaker trips only a couple of times per day.

 

[Ravenvalor]

Check it as you would any circuit. Use a meter and isolate the portions of the circuit one at a until the fault is no longer there. This could be as simple as a. Continuity check between hot and the equipment ground up to megging the circuit. Find someone with experience and watch or assist if you can.

Due to the fact that it is reading arc fault to ground does this mean that the hot or the neutral is touching the ground? I was assuming that it was reading an actual arc occuring.

 

[Dennis Alwon]

Never saw an afci that stated why it tripped. I didn't even know they made afci 9 years ago.

 

[Ravenvalor]

Never saw an afci that stated why it tripped. I didn't even know they made afci 9 years ago.

Siemens makes them.

 

[curt swartz]

How do you know its an arc fault to ground? The 2 LED indicators are ground fault and arc fault.

I tested a Siemens AFCI a while back by connecting 2 Knopp testers (Wiggy type) in parallel between the hot terminal of the breaker to the neutral buss in the panel. The breaker tripped and both indicators lit after resetting the breaker. A single tester was not enough current to trigger the GFP in the breaker is the reason I used 2. I'm not sure why the arc fault LED would light. I don't know how usefully the indicators really are.

 

[Ravenvalor]

How do you know its an arc fault to ground? The 2 LED indicators are ground fault and arc fault.

I tested a Siemens AFCI a while back by connecting 2 Knopp testers (Wiggy type) in parallel between the hot terminal of the breaker to the neutral buss in the panel. The breaker tripped and both indicators lit after resetting the breaker. A single tester was not enough current to trigger the GFP in the breaker is the reason I used 2. I'm not sure why the arc fault LED would light. I don't know how usefully the indicators really are.

I am not surprised to hear someone else's doubts about the indicator lights being useful.

 

[kwired]

I am not surprised to hear someone else's doubts about the indicator lights being useful.

Connect a test load from hot to ground. It should trip because of ground fault in this situation. See what indicators tell you.

Don't forget when testing things that neutral current returning through unintended paths is still a ground fault and will operate the trip device.

 

[Ravenvalor]

How do you know its an arc fault to ground? The 2 LED indicators are ground fault and arc fault.

I tested a Siemens AFCI a while back by connecting 2 Knopp testers (Wiggy type) in parallel between the hot terminal of the breaker to the neutral buss in the panel. The breaker tripped and both indicators lit after resetting the breaker. A single tester was not enough current to trigger the GFP in the breaker is the reason I used 2. I'm not sure why the arc fault LED would light. I don't know how usefully the indicators really are.

The instruction manual that came with the breaker states that if both LEDs are lit then there is an arc fault to ground. The website might have more information. http://www.sea.siemens.com/afci

Meanwhile the customer emails me daily with an update. The breaker trips for no apparent reason. I will probably have to check all of the receptacles, switches, lights and smoke detectors on the circuit.

Thank you for the help.

 

[ELA]

Have you, or can you ,measure the the Grounding conductor or differential current?
If I remember correctly AFCI's detect between 30 -50ma of "differential current" before they trip?

It may be that there is a "constant leakage to ground" situation but one that that is not quite above that "ground fault" threshold.
Then when load is turned on/off it creates enough transient energy to trip the arc fault portion?

In any case I am a believer in collecting data and at a minimum differential current should be measured and recorded over time if possible.

 

[WIMaster]

While it was not a problem for the last 9 years, I would kindly ask what they are connecting to that circuit and check the equipment also.
AFCIs can be a real PIA when they start plugging stuff in to them! :rant:
AFCIs don't like a lot of "normal" interference noise amongst other things. :happysad:

 

[Ravenvalor]

Have you, or can you ,measure the the Grounding conductor or differential current?
If I remember correctly AFCI's detect between 30 -50ma of "differential current" before they trip?

It may be that there is a "constant leakage to ground" situation but one that that is not quite above that "ground fault" threshold.
Then when load is turned on/off it creates enough transient energy to trip the arc fault portion?

In any case I am a believer in collecting data and at a minimum differential current should be measured and recorded over time if possible.

Intriguing, I will look into this, thanks.

 

[Ravenvalor]

While it was not a problem for the last 9 years, I would kindly ask what they are connecting to that circuit and check the equipment also.
AFCIs can be a real PIA when they start plugging stuff in to them! :rant:
AFCIs don't like a lot of "normal" interference noise amongst other things. :happysad:

All of the light switches are off, everything is unplugged, the only thing left are 7 - smoke detectors and we are going to change those next week.
Thanks.

 

[John120/240]

, the only thing left are 7 - smoke detectors and we are going to change those next week.
Thanks.

Yes smoke dectors do have a useful life span, but have you found the

problem ? Don't let the smoke dectors be the scapegoat & the problem still

exist.

 

[George Stolz]

Did I hear someone say Megger? :happyyes: