All AFCI Breakers Tripped

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JDH80

Member
Hey guys...super long time lurker here, purchaser of Mike's material to use in my educational programs that we run at the University, and I'd argue a fairly arguable guy from an electrical perspective (B.S. in Electrical Engineering, went through IBEW apprenticeship, and have about 20 years experience working on power systems at fairly high levels (MV protection, NETA device testing, construction...etc).

ANYWAYS. I had something happen last night at my house that I cannot explain. I built a new house around 2 years ago...had an electrical contractor do all the interior wiring, less a few items (added 100 amp subpanel, installed main service from the meter to the street, outbuilding). At any rate, I haven't had one issue and I am super meticulous (as well is the local code office) so I am fairly (99.9%) certain everything is correct.

Last night I feel asleep on the couch watching the baseball game...at about 2 am I wake up and go to put, plug my phone into charge(its at 1%) and about 10 minutes later I hear the phone beep (like it came off the charger) and I notice the alarm clock is off.

So I getup and notice that some circuits in the house have power and others do not. I go down to the panel and noted that EVERY AFCI was tripped! I reset them and no more issues. I also got on the interwebs to check the electric company's outage website and I notice right down the road there was an outage affecting 15 people. I couldn't sleep!!

I do have a whole house surge protector on my main panel in the top right position...it's fine (green light on). My theory is that there was some kind of transient from the utility (and perhaps the MOV (surge protector) closed) caused this to occur? I understand very well how AFCI, GFCI, and all protective devices work including relays for MV protection, heck I even now how to perform power system studies...this situation at my house has me baffled.

Any ideas?!!?!
 

MAC702

Senior Member
Location
Clark County, NV
...I understand very well how AFCI,... devices work...

Well, you're the first.

I think you nailed it with something related to the local outage. Can you ask a neighbor if they experienced the same thing you did?

It would be nice to not experience any failures during the Seahawks game!
 

JDH80

Member
Yup...asking the neighbor is the next step. I need to get a tool off of him today that I loaned him awhile back.

Probably a transient from the outage down the road, not sure if there houses are new enough to have AFCI's and I doubt they have a whole house surge protector. I work with the EDC (West Penn Power) professional so I will call their command center and see if they can corroborate an event around that time.

I guess the other option is to install a Fluke 430 on my system or perhaps a Schneider Ion7550 :) OVERKILL.

The way the Steelers season is going I think it might be better if the power does go out during the game!
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Hey guys...super long time lurker here, purchaser of Mike's material to use in my educational programs that we run at the University, and I'd argue a fairly arguable guy from an electrical perspective (B.S. in Electrical Engineering, went through IBEW apprenticeship, and have about 20 years experience working on power systems at fairly high levels (MV protection, NETA device testing, construction...etc).

ANYWAYS. I had something happen last night at my house that I cannot explain. I built a new house around 2 years ago...had an electrical contractor do all the interior wiring, less a few items (added 100 amp subpanel, installed main service from the meter to the street, outbuilding). At any rate, I haven't had one issue and I am super meticulous (as well is the local code office) so I am fairly (99.9%) certain everything is correct.

Last night I feel asleep on the couch watching the baseball game...at about 2 am I wake up and go to put, plug my phone into charge(its at 1%) and about 10 minutes later I hear the phone beep (like it came off the charger) and I notice the alarm clock is off.

So I getup and notice that some circuits in the house have power and others do not. I go down to the panel and noted that EVERY AFCI was tripped! I reset them and no more issues. I also got on the interwebs to check the electric company's outage website and I notice right down the road there was an outage affecting 15 people. I couldn't sleep!!

I do have a whole house surge protector on my main panel in the top right position...it's fine (green light on). My theory is that there was some kind of transient from the utility (and perhaps the MOV (surge protector) closed) caused this to occur? I understand very well how AFCI, GFCI, and all protective devices work including relays for MV protection, heck I even now how to perform power system studies...this situation at my house has me baffled.

Any ideas?!!?!




If the distribution outage created an arc before the lateral fuse blew, its possible the AFCIs saw the signature and tripped. Resi AFCIs are extraordinarily dumb creatures, they do not discriminate or differentiate the origin of the signature (line or load side). They see and simply trip.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
181028-1337 EDT

I have no experience with AFCIs, and don't want any. I have no GFCIs in my home, but I have run experiments on GFCIs and done some analysis. Mostly on Leviton.

MOVs are a voltage limiter, but not very good. Better than nothing, and more better if there is a main panel MOV with the addition of MOVs next to equipment needing protection. An MOV is a nonlinear resistance, and needs a source impedance as current limiter. This source impedance is wire resistance, and source wiring inductance starting from the point where the transient enters or is generated. Look at the VI curve for an MOV usable at your nominal voltage. It is fairly soft. An MOV or any other transient voltage limiter does nothing for dv/dt or di/dt.

Did the AFCIs trip on detection of what they thought was an arc signature, or is there a circuit layout or design reason that a large dv/dt transient coupled into the gate of the SCR that trips the device.

In the Leviton GFCIs that I played with there was a long trace on the PCB, about 1 ", that led to the SCR gate. This trace should not have gone directly the SCR gate, but rather there should have been a series resistance in that path, 100 to 1000 ohms, connected directly at the gate terminal, and possibly some added capacitance from gate to cathode, to provide a low pass filter. With this filtering capacitively coupled transients to the long trace would have their magnitude greatly reduced at the gate.

Experiments with said Leviton GFCI produced false tripping when an inductive load was switched off. There is too much filtering on the unbalanced current input for this to have been the path that caused tripping. Thus, it had to come in more directly to the gate.

.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
I wouldn't get all hung up with trying to figure out what happened. They were just doing what they were designed to do- make money for the manufacturers and annoy people.

-Hal
 

ramsy

Roger Ruhle dba NoFixNoPay
Location
LA basin, CA
Occupation
Service Electrician 2020 NEC
An MOV or any other transient voltage limiter does nothing for dv/dt or di/dt.

Experiments with said Leviton GFCI produced false tripping when an inductive load was switched off.

Is dv/dt or di/dt something affected by a Line Filter/Reactor?

Are other GFCI designs better at toleranting noise from computers & high-efficiency appliance motor/drives?
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
181028-1538 EDT

ramsy:

The derivative (calculus), such as dv/dt, is a measure of the slope of a curve, in this case voltage vs time. Slope is a measure of rate of change of one variable to another. The steeper a slope is the faster the one variable is changing relative to the other. A faster change of voltage means high frequency components in the voltage waveform. As frequency increases the impedance of a capacitor decreases. Thus, a faster rate of change of voltage with respect to time means that current from that changing voltage can more easily couple thru stray capacitance to the something that capacitance is to.

A low pass line filter, such as Corcom, will reduce high frequency components at its output that come into the filter input side. High frequency components generated on the output side will not be much reduced on the output side, but will be reduced at the input.

The tests I ran on Leviton GFCIs were with an 8 ft Slimline magnetic ballast light. I can randomly get 4000 V transients from switching such lamps. I don't know how different manufacturers compare, or whether Leviton may have changed their design. Note: the transient from the Slimline is a result of inductive kick.

Whether switching supplies, such as in computers, produce much inductive kick back to the AC line I don't know.

.



 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
It seems to me that it is unlikely that a "normal" AFCI trip occurred due to an upstream signature, since that would require a circuit current in each of the circuits that is greater than the series arc threshold (about 8 amps).
More likely it was a dv/dt related GF trip or simply an AFCI glitch. The other common cause for all AFCIs to trip is excess RF energy.

Sent from my XT1585 using Tapatalk
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Presuming there are AFCI breakers on both L1 and L2 (I didn't want to say "phases" ;)), the one thing they have in common (no pun intended) is the neutral. Could there have been a neutral damage? Can you ask if the POCO will share what happened?
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
181028-2154 EDT

peter d:

I have a 50 kVA pole transformer. Continuous this might supply 200 A. But there is wimpy wire for about 80 ft. Thus, at 200 A there would be considerable voltage drop. A 10 A load from neutral to hot produces a voltage change of about 0.9 V. At 200 A this would be about 18 V. My average total loading is only about 1500 W to 2000 W, and if balanced about 8 A. If balanced I would only see about 0.4 V change for for a 120 load.


ptonsparky:

Tom thanks, but I think playing with GFCIs is probably long past for me.

.
 

peter d

Senior Member
Location
New England
181028-2154 EDT

peter d:

I have a 50 kVA pole transformer. Continuous this might supply 200 A. But there is wimpy wire for about 80 ft. Thus, at 200 A there would be considerable voltage drop. A 10 A load from neutral to hot produces a voltage change of about 0.9 V. At 200 A this would be about 18 V. My average total loading is only about 1500 W to 2000 W, and if balanced about 8 A. If balanced I would only see about 0.4 V change for for a 120 load.

What I'm asking is just how old is your house that you have no GFCI's? Or did you purposefully remove them? I just find it interesting. That's all.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
181030-1938 EDT

peter d:

My house is 52 years old, all Sq-D QO, one main and five subpanels, all copper, all Hubbell, all Kirlan, many Lithonia, GE RR relays, and Buchanan crimp connections. GFCIs did not exist. We were in the early days of integrated circuits, not far along in use of transistors. SCRs came along about 1960. Before that it was vacuum tubes, thyratrons, and ignitrons. In the summer of 1952 I made a point contact transistor in my Brooklyn YMCA room while stationed at the Naval Shipyard.

Do I need AFCIs no. Would some GFCIs be good? Probably. Do I need or want tamper resistant sockets? No. Do I have any Hubbell sockets with poor contact force? No. Do I use most of my receptacles? No. Do I use QO breakers as switches? Yes for some. Do I have GE RR relay failures? Very few. I have Anaconda romex.

Also no reason to replace any QO breakers. No main breaker. Main panel disconnect is two long 200 A fuses, better than a circuit breaker, very large air gap, and visible it has been opened.

.

.
 
Last edited:

peter d

Senior Member
Location
New England
181030-1938 EDT

peter d:

My house is 52 years old, all Sq-D QO, one main and five subpanels, all copper, all Hubbell, all Kirlan, many Lithonia, GE RR relays, and Buchanan crimp connections. GFCIs did not exist. We were in the early days of integrated circuits, not far along in use of transistors. SCRs came along about 1960. Before that it was vacuum tubes, thyratrons, and ignitrons. In the summer of 1952 I made a point contact transistor in my Brooklyn YMCA room while stationed at the Naval Shipyard.

Do I need AFCIs no. Would some GFCIs be good? Probably. Do I need or want tamper resistant sockets? No. Do I have any Hubbell sockets with poor contact force? No. Do I use most of my receptacles? No. Do I use QO breakers as switches? Yes for some. Do I have GE RR relay failures? Very few. I have Anaconda romex.

Also no reason to replace any QO breakers. No main breaker. Main panel disconnect is two long 200 A fuses, better than a circuit breaker, very large air gap, and visible it has been opened.

.

.

Sounds like my ideal electrical system. :thumbsup:
 

JPinVA

Senior Member
Location
Virginia
I go down to the panel and noted that EVERY AFCI was tripped!

POCO transient that met the arc signature makes sense.

Look on the bright side, you've performed your AFCI tests for the year (or is it six?...three?...months...I forget).
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
POCO transient that met the arc signature makes sense....
Not really, since the chances that there was current above the gating amperage (7-8A for series arc signature, 40+ amp for parallel arc signature?) on each and every circuit are slim.

Whatever it was either caused a false GF trip or just plain glitched the electronics in all of the AFCIs.
 
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