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I recommend exercising breakers to my customers.

  • Yes I recommend this often

  • It's a valuable service but I do not recommend

  • Not a chance, not worth the risk

  • I have never heard of this, but I'm going to learn more.

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Any one here exercise circuit breakers for their residential customers? NFPA 70B recommended this be performed annually to keep the contacts clean and to displace the lubrication. The result should ensure faster operation when needed.
 

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Any one here exercise circuit breakers for their residential customers? NFPA 70B recommended this be performed annually to keep the contacts clean and to displace the lubrication. The result should ensure faster operation when needed.
Slightly hard for the HO'ers that pur refrigerators and other assorted barriers in front of their load centers. :LOL:
 

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I normally avoid touching any more circuit breakers than I have to to do my job. If the circuit breaker won't reset, the client will blame you and now you have argue with them about getting paid to fix what ever the problem is.

One other thing I do is to look over the handle positions of breakers when I open a panel. If I find a breaker that is off, I generally will not turn it on. It might be off for good reason. I also want to know which breakers were off in case I trip a breaker accidentally. I will reset one's I trip.

If I am hired to do an inspection of the electrical system, then I definitely exercise all the breakers. I explain to the client beforehand that testing the system may find faults that have to be repaired at their expense. It's not uncommon for me to find breakers with handles that feel weird, or are sticking either open or closed. One time I found a main breaker that would not reset properly. After slamming it closed a bunch of times it finally held. I advised the client it needed replacement. They said they needed to think about it and I never heard back.
 

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I pretwist and then use wire nuts. Solder pots rule.
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Any one here exercise circuit breakers for their residential customers? NFPA 70B recommended this be performed annually to keep the contacts clean and to displace the lubrication. The result should ensure faster operation when needed.
NFPA 70B does not cover single occupancy residential.
You touch it, you own it.
 

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Chief Flunky
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70B is better than NETA MTS but either way the manufacturers all refer to NEMA AB4 which does say inspect and exercise annually.

Realistically failure rates on 15 and 20 A non-FPE breakers are pretty low. And if it fails the worst case is the main catches it, or maybe (big maybe) the utility cutout eventually. IEEE gold book has data showing at 600 A and above failure rates are 3 times higher than below. It’s old data and not much to go on but it’s the best reliability data available on molded case breakers. It kind of makes sense...more current, bigger springs and mechanisms, so “engineered” with little if any safety margin since they are already pushing into insulated case territory.

Of those failures the dreaded arc flash is like 4%, most are either won’t close or won’t trip. Granted IEEE is industrial plants but they use the same breakers.
 

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Realistically failure rates on 15 and 20 A non-FPE breakers are pretty low. And if it fails the worst case is the main catches it, or maybe (big maybe) the utility cutout eventually.
I agree the failure rate is low, but it's not zero. I've experienced breakers that were locked on several times.

If a 20 amp breaker fails to trip on a high resistance short, the main breaker is unlikely to "catch it" because the (for example) 60 amps coursing through the wire is well below it's trip level. In a residential setting where NM is being used, that wire will glow cherry red and set fire to whatever flammables it happens to be in contact with.

Flammables include the backing paper of fiberglass insulation, the cardboard boxes stacked in the attic, improperly fire-treated ground newspaper insulation, and various studs, joists, and plywood panels.
 

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I've yet to ask customers to row through their breakers on an annual basis. As a new business owner and operator I'm curious what some of the big dogs have to say about this. On one hand it sounds like a good sales pitch for a warranty service and on the other, bankruptcy. I've always left what's working alone unless it's grossly out of date (fuse panels) or clearly physically damaged.
 

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I might mention it to a customer if it comes up in conversation. People are more concerned with water leaks than electron leaks.
 

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I used to tell people at plant electrical safety meeting to do it in the fall when they turn there clocks back and check smoke alarms at that time. But I always said to exercise ONLY the small breakers not the main.
 

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Industrial and large commercial breakers but never residential.
To me "exercising" a breaker means removing the breaker and actually creating a short to see if it trips at it's rated amperage.
Special equipment was used for the test and the test was done inside a cabinet or behind a blast wall.
If you can convince a homeowner just turning the breaker off and on is required yearly and you get enough to fall for it, you could probably make some good money.
You could even provide a certificate for them to show their homeowner's insurance company.
If you could get three a day at $100 each for 260 days a year you could pull in $78K.
About the time you finished the last one it would be time to start over with the first one.
Just don't let them watch what you're doing.
 

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I believe in periodically opening and closing the breaker to move the internals.

Just yesterday I had to turn off a 20 year old range breaker. Wouldn’t move no matter how hard I pushed. Told the home owner I’m gonna hit with the Klein’s and then they will need a new breaker.

Took 3 hits, each progressively harder, to get it to turn off. Never had that problem before.
 

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Industrial and large commercial breakers but never residential.
To me "exercising" a breaker means removing the breaker and actually creating a short to see if it trips at it's rated amperage.
Special equipment was used for the test and the test was done inside a cabinet or behind a blast wall.
If you can convince a homeowner just turning the breaker off and on is required yearly and you get enough to fall for it, you could probably make some good money.
You could even provide a certificate for them to show their homeowner's insurance company.
If you could get three a day at $100 each for 260 days a year you could pull in $78K.
About the time you finished the last one it would be time to start over with the first one.
Just don't let them watch what you're doing.
Where did you get this information?
 

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Chief Flunky
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I've yet to ask customers to row through their breakers on an annual basis. As a new business owner and operator I'm curious what some of the big dogs have to say about this. On one hand it sounds like a good sales pitch for a warranty service and on the other, bankruptcy. I've always left what's working alone unless it's grossly out of date (fuse panels) or clearly physically damaged.
In reliability engineering at one time the theory was just rebuild/replace it whenever it reaches “end of life”. The plants doing this have tons of problems right after an outage. Statistically it’s a bad idea. This was born the “bathtub curve” that adds the idea of infant mortality. For example imagine if we disconnect every wire and Megger say every 3 years. What is the chance of finding a bad wire compared to messing up the termination (not tightened properly, landed on wrong terminal)?

Nolan and Heap famously went out and measured failure curves and found 7 different patterns. Electrical equipment is pretty much random except wear areas like contactors or lubrications like breaker exercising. Those are similar to changing tires on your car and changing the oil. Plus breakers fail “silently” so the only way to find out if there are failures is inspections. Then the question is if it fails...does it matter? If not, run to failure.
 

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Chief Flunky
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Industrial and large commercial breakers but never residential.
To me "exercising" a breaker means removing the breaker and actually creating a short to see if it trips at it's rated amperage.
Special equipment was used for the test and the test was done inside a cabinet or behind a blast wall.
If you can convince a homeowner just turning the breaker off and on is required yearly and you get enough to fall for it, you could probably make some good money.
You could even provide a certificate for them to show their homeowner's insurance company.
If you could get three a day at $100 each for 260 days a year you could pull in $78K.
About the time you finished the last one it would be time to start over with the first one.
Just don't let them watch what you're doing.
NEMA AB4 says exercising is turning it off and on a couple times. They also recommend visual inspection...look for damage. That’s it. They mention testing which is what you are describing but there is no frequency on it and they don’t recommend testing all breakers.

As to your blast wall and all that silly stuff I can safely stand inches away from a 3000 A breaker under test. So on that breaker I need around 20,000-30,000 A to get it to instantaneous trip. This can be done with the largest primary injection testers. BUT it only puts out about 1 V. So you can’t even get a shock. Big difference.
 

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NEMA AB4 says exercising is turning it off and on a couple times. They also recommend visual inspection...look for damage. That’s it. They mention testing which is what you are describing but there is no frequency on it and they don’t recommend testing all breakers.

As to your blast wall and all that silly stuff I can safely stand inches away from a 3000 A breaker under test. So on that breaker I need around 20,000-30,000 A to get it to instantaneous trip. This can be done with the largest primary injection testers. BUT it only puts out about 1 V. So you can’t even get a shock. Big difference.
The equipment that was at the shop was behind a 2x4 plywood movable wall.
Maybe blast wall is not the correct terminology.
The owner of the shop had been around a long time and he did not want anyone near the test area.
His shop, his equipment, he signs the checks, if he wants employees away and protected, I had no problem with that.
None of us were electrical engineers at the time.
I was a journeyman inside wireman of about 7years at the time and had never seen a breaker tested nor the test equipment.
 

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Chief Flunky
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The equipment that was at the shop was behind a 2x4 plywood movable wall.
Maybe blast wall is not the correct terminology.
The owner of the shop had been around a long time and he did not want anyone near the test area.
His shop, his equipment, he signs the checks, if he wants employees away and protected, I had no problem with that.
None of us were electrical engineers at the time.
I was a journeyman inside wireman of about 7years at the time and had never seen a breaker tested nor the test equipment.
It’s big and heavy. Most common around here is the ETI 4000B. Almost 400 pounds of beast, mostly from the 45 kVA transformer. The newer ones are modular with boxes that each weigh around 100 pounds each like the SMC Raptor. The combined weight is the same but it doesn’t take three guys to try to roll it on and off the trailer and you can move it from area to area instead of lugging breakers all over the plant. Then there is the generator needed to run it too which will be a tow behind or rig something up.

So yeah it’s a LOT of amps. So big hardware, either several parallel cables or bus bars to get the reactance down. But almost no voltage. You don’t want “real voltage”. For one thing that requires a LOT of power....becomes impractical very quickly. Plus you don’t want to do a “real world” test. To pass UL some breakers are only rated for 50 cycles maximum at full AIC. Only high current labs actually test at full current AND voltage.
 
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