Is there such a thing as a weak breaker

RRJ

Member
Location
atlanta georgia
Occupation
Electrician
Even as far back as the early 80's the residential breaker lines were also being built out of the US, in places like Ireland. I have no idea the primary source of those products today.

I have ordered some cutler hammer breakers before COVID and they are making them in Dominican Republic.


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kwired

Electron manager
Location
NE Nebraska
Even as far back as the early 80's the residential breaker lines were also being built out of the US, in places like Ireland. I have no idea the primary source of those products today.

I have ordered some cutler hammer breakers before COVID and they are making them in Dominican Republic.


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Pretty sure CH is also being assembled in Mexico, like almost right next to the Square D plant, from what I have read. Covid supposedly shut both plants down for a while at one point.
 
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jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
Retired Electrical Engineer - Power Systems
Well ... whatever it is that assures a breaker will never lose its amperage rating is fine and dandy, all I know for certain is many times I have swapped out a failing breaker with a brand new breaker and the problem amazingly goes away.
Based on the number of breakers produced in a year and the number of breakers already installed, statistically you will come across failures, even if manufacturing turned out 99.999% good units.

In my opinion replace the breaker, don't bother with why it failed. I know some manufacturers offer lifetime warranty on residential breakers.
 

kwired

Electron manager
Location
NE Nebraska
Based on the number of breakers produced in a year and the number of breakers already installed, statistically you will come across failures, even if manufacturing turned out 99.999% good units.

In my opinion replace the breaker, don't bother with why it failed. I know some manufacturers offer lifetime warranty on residential breakers.
Lifetime warranty? Not worth effort on a $4-5 single pole standard breaker. Supply house or retailers probably aren't taking them back unless maybe it is within a year of mfg date, and cost of shipping it back to mfg sort of not worth it vs just purchasing a new one.

AFCI's? Maybe Then you find out new one still trips as there is something going on that is either a fault or simply is a condition that the AFCI doesn't play well with.
 

FionaZuppa

Senior Member
Location
AZ
COTS ocpd's all appear to be "best effort". Work most of the time as expected they would, and other times do not work as expected.

Who's testing the xFCI ocpd's on a regular basis? I do mine once/yr and last year found two bad xFCI breakers, one would intermittently fail to trip off, the other just hummed and started to smoke. Not sure if they were weak, but they did appear to be faulty.

"Testing" xFCI recept's.... haven't pressed a test button there in probably 10yrs. If one trips I will reset it, test it, then reset back.
And o yeah, you on your ladder testing your smoke alarms monthly too, right?

And then you have the other ~90% of std ocpd's, so how exactly do you test them, or do we just accept it's a "ocpd" that should do the job it is suppose to do?

All "best effort" "feel good" stuff. ;)
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
Retired Electrical Engineer - Power Systems
Back in 2008 there was a technical report written by a UL engineer called Residential Electrical System Aging Research Project. I do not know if it was ever published.
They took electrical components from 40 year or older houses that were being demoed. The breaker portion findings were summarized as:
Although circuit breakers of the 15- or 20-ampere size are permitted to trip within one or two minutes at 300% or 200% of rated current, most tripped within 10 or 20 seconds. Of the 421 circuit breaker poles tested, five (5) did not calibrate properly, as indicated by a failure to trip or the inability to open all poles when it did trip.
All five of the reported failures were install in outdoor combo meter-panels where the enclosure may not have been providing proper protection.

Evidently our industry is not overly concerned with the loss of, or reduction in, the protection provided by residential breakers. This is the only independent study I am aware of that was not brand specific.
 

myspark

Senior Member
Location
SCV Ca, USA
Occupation
Retired EE
Circuit breakers eg GFI, GFCI being synonymous with AFCI have been associated with nuance tripping.
The first time I’ve read about the danger of “ARCING”. . . I decided to replace all my GFIs with AFCIs.
The house was built in 1998.

And VOILA each of the four AFCI breakers tripped the moment I turned the power on.
Good thing it was a short drive to Home Depot right up to “return merchandise” counter.

I see hay-tined fork, shovels and firemans’ axe coming my way.

OP did not specify whether it’s a GFI, GFCI, AFCI or a generic CB.
 

Russs57

Senior Member
I'll offer my experiences FWIW.

I have worked at the same building for the last 37 years. The oldest part of the building started construction in the late 1940's and opened in 1951 due to delays from a hurricane.

We have lots of different brands. A fair amount of Westinghouse, Bulldog, Trumbull, FPE. A lot of GE and Square D. A small amount ITE and Siemens. Most of the real new stuff is Eaton.

We used to do a lot of testing on larger breakers including current injection testing. So I won't be talking about 20 amp single pole breakers.

Breakers that fail current injection testing tended to do so because they didn't trip when they should have....as opposed to too early or low of current. They seem to mostly be ones with outboard solid state trip units. They were cheap and easy to repair/rebuild/retrofit.

The older Square D micrologic breakers are bad for working and testing fine, and then totally failing with little advance notice. Unless it is the rating plug (and it never is) there is no repairing them. Since mine are all LSIG types they are very costly, and it some cases Square D has nothing that will fit the bus bars in your gear.

A lot of folks will cringe when they see the FPE name. Keep in mind I'm talking 3 phase 600 volt class stuff.....but for me it was very solid and well engineered switch gear. The only problem area is they tended to fail megger tests from phase to phase. Never caused any problems in actual use though. Occasionally I'd have to replace a shunt trip coil when a breaker didn't trip on ground fault. The only breakers of theirs I had problems with with motor operated ones on my generator PSG.

The old GE switch gear was built like a tank but unfriendly to work on live. Spacers between bus bars and breakers, lot of back wired stuff you couldn't get to, special purpose relays that were hard to source, things like that (it was also a generator board). A have never had a GE TRI-Break breaker go bad. The mains were rack out Westinghouse and occasionally I'd have replace outboard solid state trip unit.

The old Bulldogs still work but the Trumbulls scare me. The new Eaton stuff hasn't caused any problems yet, but the boards look really cheaply made. Thin gauge metal, stripped screws, badly rusting. You just know it isn't going to last.

As far as weak breakers....yes I think it happens given enough time. A common situation for me will be something like a condenser water pump has been running (more or less) 24/7/365 for 15 years. All of a sudden the breaker at the pump trips half a dozen times in a week. Breaker in the MCC never trips, Overload relay never trips. Motor megs fine and all connections are good. Put a new Square D 3 pole/480 VAC 60 amp breaker in and I'm good to go. And yes, it does seem to be mostly Square D but then I have a lot more of them.
 

paulengr

Senior Member
Back in 2008 there was a technical report written by a UL engineer called Residential Electrical System Aging Research Project. I do not know if it was ever published.
They took electrical components from 40 year or older houses that were being demoed. The breaker portion findings were summarized as:

All five of the reported failures were install in outdoor combo meter-panels where the enclosure may not have been providing proper protection.

Evidently our industry is not overly concerned with the loss of, or reduction in, the protection provided by residential breakers. This is the only independent study I am aware of that was not brand specific.
It exists. And more than just breakers.

 

paulengr

Senior Member
I'll offer my experiences FWIW.

I have worked at the same building for the last 37 years. The oldest part of the building started construction in the late 1940's and opened in 1951 due to delays from a hurricane.

We have lots of different brands. A fair amount of Westinghouse, Bulldog, Trumbull, FPE. A lot of GE and Square D. A small amount ITE and Siemens. Most of the real new stuff is Eaton.

We used to do a lot of testing on larger breakers including current injection testing. So I won't be talking about 20 amp single pole breakers.

Breakers that fail current injection testing tended to do so because they didn't trip when they should have....as opposed to too early or low of current. They seem to mostly be ones with outboard solid state trip units. They were cheap and easy to repair/rebuild/retrofit.

The older Square D micrologic breakers are bad for working and testing fine, and then totally failing with little advance notice. Unless it is the rating plug (and it never is) there is no repairing them. Since mine are all LSIG types they are very costly, and it some cases Square D has nothing that will fit the bus bars in your gear.

A lot of folks will cringe when they see the FPE name. Keep in mind I'm talking 3 phase 600 volt class stuff.....but for me it was very solid and well engineered switch gear. The only problem area is they tended to fail megger tests from phase to phase. Never caused any problems in actual use though. Occasionally I'd have to replace a shunt trip coil when a breaker didn't trip on ground fault. The only breakers of theirs I had problems with with motor operated ones on my generator PSG.

The old GE switch gear was built like a tank but unfriendly to work on live. Spacers between bus bars and breakers, lot of back wired stuff you couldn't get to, special purpose relays that were hard to source, things like that (it was also a generator board). A have never had a GE TRI-Break breaker go bad. The mains were rack out Westinghouse and occasionally I'd have replace outboard solid state trip unit.

The old Bulldogs still work but the Trumbulls scare me. The new Eaton stuff hasn't caused any problems yet, but the boards look really cheaply made. Thin gauge metal, stripped screws, badly rusting. You just know it isn't going to last.

As far as weak breakers....yes I think it happens given enough time. A common situation for me will be something like a condenser water pump has been running (more or less) 24/7/365 for 15 years. All of a sudden the breaker at the pump trips half a dozen times in a week. Breaker in the MCC never trips, Overload relay never trips. Motor megs fine and all connections are good. Put a new Square D 3 pole/480 VAC 60 amp breaker in and I'm good to go. And yes, it does seem to be mostly Square D but then I have a lot more of them.
I’ve tested lots of Tri-breaks that fail. Mostly the trip unit just quits working. It’s not all that common but it happens to about 3-5% of the ones I’ve tested. Used to not be that high but that was 20 years ago. It has reached a point where sales dropped a customer over it.

In terms of old ANSI stuff the breakers themselves have various mechanical and electrical issues. As for trip units the originals used mostly induction disc relays or something similar. You can’t go into an old power plant or substation without finding row upon row of relays although most are abandoned. Calibration drift is and always was a problem. The “best” ones just have crazy large tolerances. They got it written into the standards that fuses have to represent the min and max curves but not breakers. If they did nobody would bother with induction disc relays. The biggest problem over time is they lose their induction/capacitive properties. The curve becomes flat. So you have to choose to either calibrate to the center or one of the ends of the curve and the rest is out or rebuild/replace. With the cost so high that microprocessor relays that can replace an entire wall of relays makes more sense. The only practical way to test them is with simulated currents and voltages. Even then the manufacturers all have very screwy test procedures that are very questionable, especially GE.

In the 1990s for about ten years everyone was selling an “improved” solid state relay as a more accurate, more reliable relay. They were essentially analog op amp circuits. Calibration drift was gone, at least initially. Then the failures started where they just outright failed. It was worse than the induction disc relays. The Square D early Micrologic trip units, Baslers, some ABB units, all the same. It all comes down to typical electronics failures. There are little to no surplus units because the failure rates are so high. Again injecting test currents and voltages is the way to test.

The latest generation are the microprocessor based trip units which have been in service about 25 years. For whatever reason the reliability seems greatly improved even from one brand to another and accuracy is much improved and drift seems to be nonexistent. They seem to either work 100% or 100% fail. Lots of variations from the old Digitrips to the latest SELs which are basically the PLCs of relays to hybrids like ABB Circuitshields and Startco/Littelfuse units that still use “taps” and except for electronics and needing fewer relays, they are the same as the old induction disc setups. They have become so reliable that even very large companies with their own relay crews like Duke Power have stopped testing or test differently. I mean really we can just measure the actual currents/voltages and compare to the displayed readings. It’s an analog to digital converter so it either works or it doesn’t. Then we just need to test the output contacts and maybe run a self calibration. That’s it. Anything beyond this gets more into “type testing” which is more of a factory/design test. Primary injection testing on these relays is pointless. And if you don’t mind the considerable cost we can replace even old integral trip units with new modern microprocessor based ones fairly easily.

The problem that some people have by the way with secondary injection testing can be summed up in the way that GE does it compared to Schneider or Westinghouse. With the latter two you connect to the breaker somehow and inject low level signals into the breaker that are identical to the breaker’s sensors. The only thing not tested is the CTs which rarely fail. If there is a display you can instantly tell if they have failed (reading is zero). With GE it uses a 3 pin connection (stereo headset connector). Everything is handled digitally inside the relay. No way to tell if it’s a “true” test. Reminds me of automotive diesel manufacturers that fooled the EPA test even to the point of tuning the engine for the test. This testing works very well when it works. I’ve never been happy with primary testing. It’s all very Neanderthal and just as questionable and so much more limited to what you can test.
 

Russs57

Senior Member
Probably because all my Tri-breaks are closer to 40-50 years old.

So Paul, if it was your money....what brand/line would you buy for molded case up to 1,200 amp and rack out in the 2,000 amp size?
 

FionaZuppa

Senior Member
Location
AZ
Back in 2008 there was a technical report written by a UL engineer called Residential Electrical System Aging Research Project. I do not know if it was ever published.
They took electrical components from 40 year or older houses that were being demoed. The breaker portion findings were summarized as:

All five of the reported failures were install in outdoor combo meter-panels where the enclosure may not have been providing proper protection.

Evidently our industry is not overly concerned with the loss of, or reduction in, the protection provided by residential breakers. This is the only independent study I am aware of that was not brand specific.
Across the southwest, panels are mounted to the ext of the home. Blazing hot in summer and baking in sun, and very dusty most of the time. They are not sealed panels either. Inside the panel is always nice and dusty, fine dust too.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
Retired Electrical Engineer - Power Systems
Across the southwest, panels are mounted to the ext of the home. Blazing hot in summer and baking in sun, and very dusty most of the time. They are not sealed panels either. Inside the panel is always nice and dusty, fine dust too.
Read the report.

My point was that if our industry, and the insurance industry, don't seem to care about most residential breaker performance, regardless of the age. A few have picked on a brand or two, but again pretty much ignore the actual age of the installation.
 

paulengr

Senior Member
Probably because all my Tri-breaks are closer to 40-50 years old.

So Paul, if it was your money....what brand/line would you buy for molded case up to 1,200 amp and rack out in the 2,000 amp size?
Molded case only goes to I think 800 A. After that it’s insulated case. You can get 1200 A molded case breakers but they are 1200 A frames. Insulated case goes much higher. I have been putting in Masterpacts. That’s the last few I’ve put in. WLs are a close second but I just can’t bring myself to like them.

Personally I’m a huge fan of the ILine design. It works and it’s very reliable. They have been around almost 50 years. It’s a switchboard or panelboard but it’s still “rack out”.

Realistically I’m not a fan of racking out breakers in the traditional metal clad design. I’ve had more trouble with the rack out mechanisms than they’re worth. For the few times it matters you’re better off with bolted switchboards. Plus today the Masterpacts and WLs are the exact same breaker. Rack out just gets you a carrier. ILines are similar but anyone that has worked with them knows that irritating feeling when the stupid little screw that holds them in fails. It’s just too chintzy.

The really exciting low voltage thing is Atom Power. A 100% solid state breaker. But not up to 1200 A yet. Not even close. Not sure they will ever get there.

In medium voltage I really like what some of the smaller custom builders are doing with the Tavrida breakers. The basic breaker is vacuum. The innovative part is the magnetic actuator. You can fit a 15 kV breaker in 18” of width and depth instead of 36” wide and 60”+ deep. The only hassle with them is the oddball, low BIL ratings.
 

paulengr

Senior Member
There is a difference between the number of operations a breaker is rated for, and how many times it can TRIP. Yes, an MCCB 100A and under is rated for thousands of operations (6,000 under full load + 4,000 no load), but that "full load" is not about TRIPPING, it's only about the mechanical operations and contact life.

Under UL489, an MCCB 100A and under is only required to trip 50 times at 600% current. After that the calibration may be affected and it may start nuisance tripping. In this test sequence, if the breaker trips FASTER at 600% current on trip #50 compared to trip #1, that is stall a PASS. It is just required to trip WITHIN that the stated trip curve range, which if you look at it is wider than most people realize. Tripping at the lowest end of the range still meets the requirement.

But MORE IMPORTANTLY, it is only required to trip and reset TWICE under Short Circuit conditions. The mag trips are NOT designed for multiple tripping events and maintaining accuracy.

So can a breaker get "weak"? Defining "weak" is nebulous, but it CAN begin to nuisance trip if it is required to trip over and over and over.
Agreed 100% with the assessment as far as treating the breaker as a black box.

But now let’s step back a bit. Taking electronic trip units off the table what do we have? It’s a spring loaded coil. When the magnetic field of the solenoid overcomes the spring pressure it hits the trip bar and releases the hair trigger. This is true of all instantaneous trips in molded case breakers except the electronic kind. There may be an adjustable trip (spring preload) but that’s it. So this function can get “weak” over time as the spring relaxes. Will not be detected by UL testing because that’s short term and it should pass longer term testing because nuisance tripping “passes” the test.
 

paulengr

Senior Member
Based on the number of breakers produced in a year and the number of breakers already installed, statistically you will come across failures, even if manufacturing turned out 99.999% good units.

In my opinion replace the breaker, don't bother with why it failed. I know some manufacturers offer lifetime warranty on residential breakers.
It matters because it could be random but most of the time the cause is not just a defective breaker. That’s like replacing fuses without tracking down the short circuit. It could be over dutied (AIC too low), or overworked (a problem not eliminated), or environment. This leads to more work and more money. Don’t stop at just the protection system. Replacing a breaker is easy. Plus there is a huge difference between a 15 A residential and a 1500 A cast frame ANSI draw out breaker. One is a thousand times more expensive and often has long lead times.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
Retired Electrical Engineer - Power Systems
It matters because it could be random but most of the time the cause is not just a defective breaker. That’s like replacing fuses without tracking down the short circuit.
I did not promote randomly replacing equipment as part of troubleshooting.
I said that when the decision was made the problem was with a residential breaker, it did not make economic sense to to determine why the breaker was tripping inappropriately.

Yes, there is a huge difference between a 15A and a 1500A breaker, that is why I try to tailor my answers to fit the details provided by the OP.
I haven't researched it but I would guess the vast majority of the posts on this forum concerning breakers involve molded case circuit breakers, with the majority of those being residential ones.
 

FionaZuppa

Senior Member
Location
AZ
Why can't OCPD's make advancements using solid-state controls? Automotive brakes did, EFI fuel systems did, light bulbs did, but not OCPD's ? You could actually make one breaker that spans many many setpoints, like a single 15/20/25/30 120v where you select/set the trip setting before installation (dial wheel on side, front window showing setting, etc), hence one ocpd that can "do it all".
 

kwired

Electron manager
Location
NE Nebraska
Why can't OCPD's make advancements using solid-state controls? Automotive brakes did, EFI fuel systems did, light bulbs did, but not OCPD's ? You could actually make one breaker that spans many many setpoints, like a single 15/20/25/30 120v where you select/set the trip setting before installation (dial wheel on side, front window showing setting, etc), hence one ocpd that can "do it all".
I'd guess partly for same reasons they had to make Type S fuses.
 

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Why can't OCPD's make advancements using solid-state controls? Automotive brakes did, EFI fuel systems did, light bulbs did, but not OCPD's ? You could actually make one breaker that spans many many setpoints, like a single 15/20/25/30 120v where you select/set the trip setting before installation (dial wheel on side, front window showing setting, etc), hence one ocpd that can "do it all".
They did, you can get Solid State Trips on most 3 phase breakers now . They are more expensive though, so most people don't feel it's necessary.
 
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