megger for afci

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klineelectric

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electrical contractor
Probably a stupid question. I will be troubleshooting afci next week, trips at random once a week, cant replicate on command or when im there. I was there already months ago pulled all switches and recepts checked the usual. This time I will be bringing a megger. Assuming all wiring checks out, is there a way to check light fixtures or ceiling fans with megger. Being a residential romex jockey I have never had the need for a megger so please exuse my ignorance.
 
Take along the newest model of AFCIs for that panel. The newer CH seem to have less problems. One can only hope for the other brands. Maybe CH was the only one needing improvement. Advantage is some have diagnostics that will tell you the type of fault occuring. Real handy.

I would be careful about applying a high voltage to anything but the wiring.

Look for an old refrigerator that uses a klixon style thermostat. Pumps that cycle at night. etc etc

Good luck.
 
To clarify If I could replicate trip while there I would find it 100% of the time. Its a random trip with an unhelpful homeowner (not knowing when/how/why) breaker is tripping that is making it a pain. I ruled out all of the obvious (things plugged in, grounds touching, loose connection) which is why im going the megger route. This room is on the 1st floor with no access above or below....woohoo. Im just seeking ANY advice from the vast experience on these forums to limit trips. Thanks
 
ptonsparky said:
Take along the newest model of AFCIs for that panel. The newer CH seem to have less problems. One can only hope for the other brands. Maybe CH was the only one needing improvement. Advantage is some have diagnostics that will tell you the type of fault occuring. Real handy.

I would be careful about applying a high voltage to anything but the wiring.

Look for an old refrigerator that uses a klixon style thermostat. Pumps that cycle at night. etc etc

Good luck.
Click to expand...

Its a siemens, but I will be bringing a new breaker.
 
ptonsparky said:
Take along the newest model of AFCIs for that panel. The newer CH seem to have less problems. One can only hope for the other brands. Maybe CH was the only one needing improvement. Advantage is some have diagnostics that will tell you the type of fault occuring. Real handy.
Click to expand...


I think that all brands of AFCI produced earlier versions that tended to have problems and have been replaced by better versions. I know that square D and Siemens have had recalls on some of their earlier versions.
 
I won't be surprised when somebody discovers the newer ''less trip happy'' arc fault versions are a regular style circuit breaker with a pushbutton that trips the breaker to off position when pushed and nothing else in it that would differentiate the two other than price point...........
 
macmikeman said:
I won't be surprised when somebody discovers the newer ''less trip happy'' arc fault versions are a regular style circuit breaker with a pushbutton that trips the breaker to off position when pushed and nothing else in it that would differentiate the two other than price point...........
Click to expand...

Where can I buy some....:D
 
What type of fault do the indicator lights show on the breaker? Siemens AFCI's have indicator lights to show if its a GF or AF.
 
macmikeman said:
I won't be surprised when somebody discovers the newer ''less trip happy'' arc fault versions are a regular style circuit breaker with a pushbutton that trips the breaker to off position when pushed and nothing else in it that would differentiate the two other than price point...........
Click to expand...

This the BR series? Im getting those :D
 
klineelectric said:
Probably a stupid question. I will be troubleshooting afci next week, trips at random once a week, cant replicate on command or when im there. I was there already months ago pulled all switches and recepts checked the usual. This time I will be bringing a megger. Assuming all wiring checks out, is there a way to check light fixtures or ceiling fans with megger. Being a residential romex jockey I have never had the need for a megger so please exuse my ignorance.
Click to expand...

Meg test should pretty much help eliminate a ground fault issue - but also remember it only tests what is connected at the time of the test, should an appliance with a fault not be plugged in at the time of test you will miss it. But at same time you need to be careful with some loads and applying a high test voltage - most anything with electronics will be in this category.

So unplug all appliances that may not be suitable for such testing - maybe even unplug all cord and plug items for initial testing anyway and only test what is fixed wiring first. Turn on switches for lighting - make sure there is isolation from neutral to equipment grounding (not sure if AFCI's open the neutral or not, if they don't you will fail test immediately if you haven't separated them. Test from ungrounded conductor to equipment grounding conductor. Any low resistance (low meaning in anything in the kilo-ohm ranges or below and maybe even a low meg-ohm range reading) is going to be a problem and you need to find out what is causing that reading.

If it is actually arc-fault reasons for the trip instead of ground fault reasons - it is probably compatibility issues with the AFCI and a particular appliance and all I can say there is good luck.
 
kwired said:
Meg test should pretty much help eliminate a ground fault issue - but also remember it only tests what is connected at the time of the test, should an appliance with a fault not be plugged in at the time of test you will miss it. But at same time you need to be careful with some loads and applying a high test voltage - most anything with electronics will be in this category.

So unplug all appliances that may not be suitable for such testing - maybe even unplug all cord and plug items for initial testing anyway and only test what is fixed wiring first. Turn on switches for lighting - make sure there is isolation from neutral to equipment grounding (not sure if AFCI's open the neutral or not, if they don't you will fail test immediately if you haven't separated them. Test from ungrounded conductor to equipment grounding conductor. Any low resistance (low meaning in anything in the kilo-ohm ranges or below and maybe even a low meg-ohm range reading) is going to be a problem and you need to find out what is causing that reading.

If it is actually arc-fault reasons for the trip instead of ground fault reasons - it is probably compatibility issues with the AFCI and a particular appliance and all I can say there is good luck.
Click to expand...
Thank you kwired. This is a bedroom with only recepts, a ceiling fan and a couple of sconce lights. As I understand it I should disconnect all lights and fans and test wiring. Can I leave switches and recepts in for test. Have you heard of appliances on other circuits causing problems with afci? I read on here somewhere that light ballasts on different circuit were causing trips. This house the homeowner actually had us install a lot of antique lights which were rewired by others, but none of those lights are on this circuit. I just want as many ideas as I can get because this is on 1stfloor with no access above or below. These intermittent trips are going to send me to an early grave.
 
klineelectric said:
Thank you kwired. This is a bedroom with only recepts, a ceiling fan and a couple of sconce lights. As I understand it I should disconnect all lights and fans and test wiring. Can I leave switches and recepts in for test. Have you heard of appliances on other circuits causing problems with afci? I read on here somewhere that light ballasts on different circuit were causing trips. This house the homeowner actually had us install a lot of antique lights which were rewired by others, but none of those lights are on this circuit. I just want as many ideas as I can get because this is on 1stfloor with no access above or below. These intermittent trips are going to send me to an early grave.
Click to expand...

I'd probably leave lights and fans in the circuit, unless they have some electronic controls, otherwise it shouldn't hurt them, if nothing is wrong anyway.

I have little experience with AFCI issues, have tracked down many GFCI issues over the years - that kind of problem is going to be the same if it is a ground fault issue on the AFCI. But I also would not be surprised to see inductive kickback from another circuit cause trouble - have even seen it a time or two with GFCI's.
 
I've posted here before that one time I spent several trips to a residence to finally find that a flat screen TV when it would go to a bright white screen would cause arc fault breaker to trip and not only on its associated circuit but others also, randomly (maybe because home runs were ran in close proximity to each other) ?
Changed TV and haven't had a problem since.
 
mopowr steve said:
I've posted here before that one time I spent several trips to a residence to finally find that a flat screen TV when it would go to a bright white screen would cause arc fault breaker to trip and not only on its associated circuit but others also, randomly (maybe because home runs were ran in close proximity to each other) ?
Changed TV and haven't had a problem since.
Click to expand...

Wow, sounds like I may have to move into house to track down a random trip. Gotta love this technology.
 
kwired said:
I'd probably leave lights and fans in the circuit, unless they have some electronic controls, otherwise it shouldn't hurt them, if nothing is wrong anyway.
Click to expand...

Just to emphasize here:

An 'meggar'* is a high voltage current limited ohm meter used for testing insulation. Test voltages of 500 and 1000V or higher are quite common.

The test voltages will easily damage electronics if mis-applied. They also pack quite a wallop if you touch the leads.

The test voltages will cause surge suppression diodes to start to conduct. This may lead to incorrect results (you would read a fault when in fact the diode is correctly shunting the high voltage). This might damage the diodes (or might not, if the current limit is low enough.)

-Jon

*(Note: Meggar is a brand name, and they make high voltage insulation testing meters. They also make other sorts of meter. Other companies make high voltage insulation testing meters.)
 
Remember to remove light bulbs from the lights. Any ballasted light would need to be disconnected. I'd disconnect all plug connected equipment.

Sent from my XT1254 using Tapatalk
 
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