Microwave Tripping Arc Fault

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donselec

donselec

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Aurora, CO, USA
I have a customer who has a basement bar area that's not a kitchen, and is on a 20A arc fault breaker, a 700W microwave is tripping the arc fault. Anyone else had this problem? The breaker only protects the outlets in the bar area, maybe don't need arc fault? The outlets are also protected by a GFI receptacle--not tripping. Thanks.
 
Technically yes, it's in a family room, even though it's a bar/cooking area, unless it could be classified as a kitchen, but I don't think so. There's a kitchen upstairs and it's a single family dwelling. I just wondered if anyone else had this microwave tripping arc-fault problem, or maybe if it has something to do with the GFI. Not sure. Could be a problem with the Code too, what can you do? Thx.
 
bmwnut said:
Isn't it kinda rule of thumb If it is GFIC then it does not have to be AFIC???
I don't think you need both??
Click to expand...
I wouldn't bet my electrical licenese on that rule.
There are places in a house where both AFCI and GFCI can and will be required, and both should work together with no problems if wired correctly, an AFCI can not provide the 5ma people protection that a GFCI does, as a GCFI can not detect an arc fault, although they funtion simular when it comes to a ground fault, an AFCI will only provide 30ma of protection, which is too high to protect a person from a shock hazard.

donselec said:
Technically yes, it's in a family room, even though it's a bar/cooking area, unless it could be classified as a kitchen, but I don't think so. There's a kitchen upstairs and it's a single family dwelling. I just wondered if anyone else had this microwave tripping arc-fault problem, or maybe if it has something to do with the GFI. Not sure. Could be a problem with the Code too, what can you do? Thx.
Click to expand...

When AFCI's first came out there was many problems with them and tripping on inductive kickback from inductive loads such as the big transformer in a microwave was one of them, from what I have heard they got better (Indiana took out the requirment for AFCIs way back in 2005) also the earlyer Square D home lines were notorous for this, and they did a recall, which you can tell which one it is by the test button color, If I remember right the bad ones had a blue test button and the new ones had a green one, (maybe someone will verify this)

Also check the micro cord with a high reading ohm meter, if there is any leakage from the hot or neutral to the grounding conductor, it will cause the AFCI to trip, also inductive kick back trips happen right when the inductive load is turned off, if it is tripping when the load is turned on then it could be a grounded neutral in the circuit feeding it.

just some food for thought.
 
bmwnut said:
Isn't it kinda rule of thumb If it is GFIC then it does not have to be AFIC???
I don't think you need both??
Click to expand...

That is not true. Not to say you need both, but they are separate protections. If you have a sink in a family room with a plug next to it, it will need to be protected by both.

I'm sure you came to that conclusion because the requirements for each end up steering you in that direction, but don't overlook the possibility that you may need both protections.

Another example is some bathroom fans and/or lights over a shower that iare on the lighting circuit that also supplies the hallway and bedroom lights nearby. The circuit must be arc-fault protected and the bathroom fixture would also need to be ground-fault protected.
 
hurk27 said:
When AFCI's first came out there was many problems with them and tripping on inductive kickback from inductive loads such as the big transformer in a microwave was one of them, from what I have heard they got better (Indiana took out the requirment for AFCIs way back in 2005) also the earlyer Square D home lines were notorous for this, and they did a recall, which you can tell which one it is by the test button color, If I remember right the bad ones had a blue test button and the new ones had a green one, (maybe someone will verify this)

Also check the micro cord with a high reading ohm meter, if there is any leakage from the hot or neutral to the grounding conductor, it will cause the AFCI to trip, also inductive kick back trips happen right when the inductive load is turned off, if it is tripping when the load is turned on then it could be a grounded neutral in the circuit feeding it.

just some food for thought.
Click to expand...

Well the micro's brand new and other appliances work on the circuit, but there may be something with the micro anyway. It is a Homeline newer style AFCI
 
hurk27 said:
Also check the micro cord with a high reading ohm meter, if there is any leakage from the hot or neutral to the grounding conductor, it will cause the AFCI to trip...
Click to expand...

donselec said:
The outlets are also protected by a GFI receptacle--not tripping.
Click to expand...
The GFCI should trip before an AFCI trips on a ground fault.

Just for fun, I would pop in a Siemens AFCI into the panel and see what the indicator light says if it trips. If it did, I bet it would call it an arc fault.
 
try creating the same situation on a different circuit maybe upstairs and see if the micro trips the breaker if it does it probably the mico you could try a different micro also.
 
Why haven't you Megged it?
Why don't You put a hair dryer on that circuit?
Why don't You isolate that circuit, or run a single circuit to it?

A basement has to have GFCI, but if habitable a AFCI, frankly I only thought if your living in it! ...
seems a little loose as to what exactly is required.

No I didn't look at good book ! :mad:
 
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