AFCI hates GFCI!

[brycenesbitt]

Anyone seen this? I'm looking at a laundry room, where the AFCI breaker trips if any large load is placed.
It was reported as on the spin cycle of the washer. I was able to repeat the issue using an Instant Pot -- the moment the heater element kicks in, the AFCI trips, showing an arc fault.

The GFCI is a Leviton 07599. Siemens/Murray AFCI breaker.

Swapping for a new GFCI and all seems to work. I seem to have the worst AFCI experiences in laundry rooms!

 

[Dennis Alwon]

There is no reason an afci and gfci cannot work together. The problem may be an oversensitive unit or a bad piece of equipment but they will work as one

 

[ramsy]

..I was able to repeat the issue using an Instant Pot -- the moment the heater element kicks in, the AFCI trips, showing an arc fault.

Swapping for a new GFCI and all seems to work. I seem to have the worst AFCI experiences in laundry rooms!

Excellent troubleshooting. AFCI's separate the wheat from the chaff.

Do you mind explaining how that instant pot works?

 

[hbiss]

Do you mind explaining how that instant pot works?

It's a counter top cooking appliance like a crock pot only with other functions. It operates with a heating element of generally 1200W. There is a programmable controller for time and temperature. The actual heating element load is either switched with conventional contacts or a solid state device. The load will cycle on and off to maintain temperature.

AFCI's separate the wheat from the chaff.

I don't think AFCI's separate the wheat from the chaff, just use them enough and you will understand how useless they are.

-Hal

 

[jeff48356]

I don't think AFCI's separate the wheat from the chaff, just use them enough and you will understand how useless they are.

Very well said! I'm SO glad that the state of Michigan is wise to that, and has eliminated their requirement a few years back. It would be nice if other states would catch on and follow suit as well.

 

[ramsy]

remove unacceptable language

remove unacceptable language

..I don't think AFCI's separate the wheat from the chaff, just use them enough and you will understand how useless they are. -Hal

If AFCI's frustrate house flippers & remodel masters, then they operate as intended:

If a house Flipper's reset button wont hold, and the buyer or home inspector wants it, then Flipper is force to go inside; to become the attic rat without respirator or headlamp, to become the furniture/appliance mover without dolly or gloves, to become the free laborer without pay, to access all wall boxes in search of wiring altered by renovations.

Lacking experience with problematic appliances, or circuit tracers, or junctions buried behind walls, and confused how muti-wire circuits break SQ-D AFCI's, the fuse box Flipper publishes his manifesto-conspiracy theory on corrupt regulators that sabotage him with AFCI's.

If this sounds like you, then AFCI's have done their job.

 

[brycenesbitt]

Excellent troubleshooting. AFCI's separate the wheat from the chaff.
Do you mind explaining how that instant pot works?

Once I narrowed it to the GFCI, I pulled it, and used an old appliance cord to make a little
ever-so-safe test rig:




A small lamp worked fine.
The instant pot worked fine, until it hit the heating phase (it's a cooking appliance with a resistance heater). The AFCI tripped in about 2 seconds.
A hair dryer I, um, borrowed, tripped the AFCI, again in about 2 seconds.

Note it turns out the Instant Pot's internal relay sparks when it starts heating.
But the AFCI is cool with that: just not with whatever the GFCI is doing under load.

Weird.
Because an GFCI is basically a latching relay internally. It should not "do" anything to the circuit.

 

[romex jockey]

Very well said! I'm SO glad that the state of Michigan is wise to that, and has eliminated their requirement a few years back. It would be nice if other states would catch on and follow suit as well.

The nema reps show up and make sure it dies in legislation ....

If AFCI's frustrate house flippers & remodel masters, then they operate as intended:

.<<<,snip>>>
If this sounds like you, then AFCI's have done their job.

It sounds like CMP-2

http://www.combinationafci.com/resources/doc_iee_paper_presentation_orlando_2012_02_03.pdf


~RJ~

 

[hbiss]

Once I narrowed it to the GFCI, ... But the AFCI is cool with that: just not with whatever the GFCI is doing under load. ...Weird ...Because a GFCI is basically a latching relay internally. It should not "do" anything to the circuit.

A GFCI is a little more than that. They do have self test diagnostics and electronics too. Likely the new GFCI inadvertently suppressed the arc "noise" that the AFCI breaker was false tripping on.

Don't count on it next time though.

-Hal

 

[brycenesbitt]

To add to the irony

To add to the irony

Recall the problem would trigger when the specific GFCI was paired with the washer, a hair drier, an electric grinder from my toolkit, and the Instant Pot. It seemed that any larger load device would fault that given AFCI, but only if that specific GFCI was in line.


The irony is, the instant pot turns out to have a glowing contact, seemingly unrelated to anything else: the pot itself is defective. I saw a glow from the bottom and saw a spark. I opened it up and found what looks like a mechanical pressure switch cutoff for mains power, that's red hot and glowing. When cool the metal is all discolored:



I borrowed the glowing pot, and have tried it on several AFCI circuits: they all hold. So much for AFCI protection!


I'm still somewhat confused because the defective GFCI trips some, but not all, AFCI circuits I tried it on (I tried 5, it faulted 2 of them).

 

[kwired]

So what is tripping, the GFCI, the AFCI, both? You seem to be claiming the GFCI is the problem yet you never said whether it is tripping.

I expect some spark in any 1200 watt load when it makes or breaks. AFCI's are supposed to be able to reject that as a trip condition.

 

[hbiss]

Every time the OP replies it gets more confusing. The GFCI receptacle is not defective and causing the AFCI to trip. Rather, I believe it prevents the AFCI from tripping in some circumstances.

I borrowed the glowing pot, and have tried it on several AFCI circuits: they all hold. So much for AFCI protection!

An AFCI cannot protect against a glowing connection!

-Hal

 

[GoldDigger]

And an AFCI exposed to a constant or intermittent series arc signature (real or spurious) cannot trip until you put at least 7A of current through the circuit.

Sent from my XT1585 using Tapatalk

 

[Dennis Alwon]

And an AFCI exposed to a constant or intermittent series arc signature (real or spurious) cannot trip until you put at least 7A of current through the circuit.

Sent from my XT1585 using Tapatalk

I thought GE stated 4 amps.... I may be wrong

 

[StarCat]

10-4

10-4

It's a counter top cooking appliance like a crock pot only with other functions. It operates with a heating element of generally 1200W. There is a programmable controller for time and temperature. The actual heating element load is either switched with conventional contacts or a solid state device. The load will cycle on and off to maintain temperature.



I don't think AFCI's separate the wheat from the chaff, just use them enough and you will understand how useless they are.

-Hal

Very well spoken Hal.....

 

[brycenesbitt]

So what is tripping, the GFCI, the AFCI, both? You seem to be claiming the GFCI is the problem yet you never said whether it is tripping. I expect some spark in any 1200 watt load when it makes or breaks. AFCI's are supposed to be able to reject that as a trip condition.

To answer your question:
The GFCI never trips.
The Siemens AFCI reports an arc fault when the particular older Leviton GFCI outlet is inline.
The Siemens AFCI does not trip when a new Leviton GFCI outlet is inline.
When both are in line, the trip happens.
The arc fault happens with a washer, hair dryer, angle grinder and instant pot (so far). If I go back I'll try a toaster or some other simple resistive load.

The trip happens only under load: at small draw it holds.

---
The instant pot is defective. The glowing contact is on a pressure overload disconnect that should be normally closed. It's a literal red herring here: the pot was pulled in just to exclude the washer as the source of the problem.

 

[brycenesbitt]

The following set of tests addresses glowing contact AFCI claims:
http://combinationafci.com/resources/doc_ieee_combination_afci.pdf
COMBINATION AFCIs: WHAT THEY WILL AND WILL NOT DO
Joseph C Engel, PhD
Member, IEEE
107 Overlook Circle
Monroeville PA 15146
Presented at the 19th Annual IEEE IAS Electrical Safety Workshop, Daytona Beach, Jan/Feb 2012

I don't have a position on the glowing contact. It just came up due to the random grabbing of a test appliance for the AFCI/GFCI weirdness.

 

[hbiss]

The GFCI never trips.
The Siemens AFCI reports an arc fault when the particular older Leviton GFCI outlet is inline.
The Siemens AFCI does not trip when a new Leviton GFCI outlet is inline.

Wouldn't it be safe to assume then that the new GFCI outlet eliminates or attenuates the arc transient traveling through it so that the AFCI doesn't respond to it? And the older GFCI receptacle doesn't do that?

The only way to prove this is to look at the voltage before and after the receptacle as the condition occurs with a scope. But at this point I (at least) am pretty sure this is what's happening.

-Hal

 

[ramsy]

To answer your question:
The Siemens AFCI does not trip when a new Leviton GFCI outlet is inline.

1) Hal is asking if AFCI tripped with plain old 3-prong plug you used, when no GFCI was is inline?

2) Can you explain why AFCI code compliance was so important to you?
...a) Did you expect it required by Municipal or Home Inspection?
...b) If not inspected, do you care about property insurance Having Jurisdiction (AHJ) that deny's claims?
...c) Are you just a code wonk that does your best to follow code rules?

Most AFCI's that I install are for existing wiring, new outlets, & old work. My clients are educated why its in there best interest that no legal cause exists for property insurance to void claims, including checking the smokes & batteries.

Many remodel contractors on this forum openly refuse to install AFCI's, subjecting their clients to denial of claims by insurance investigators.

Granted owner-builder remodels are rarely inspected, and its not enforced, but I believe refusing required Smokes or AFCI's is negligent disregard for duty of care, and fails to protect owner builders from themselves.

 

[PaulMmn]

Once I narrowed it to the GFCI, I pulled it, and used an old appliance cord to make a little
ever-so-safe test rig:


View attachment 23034

Isn't that what's known as a "Little Jiffy Fuse Blower?"