Do you test your breakers?

[Qapla]

... When we renovated the electrician used all slim tandem breakers (QOT). Is there evidence that they are not as reliable as a full size breaker?

I have not seen any difference in the performance of thin vs standard breakers, The only thing I have found is that, depending on how "warm" the breaker gets when it trips, it sometimes will trip the tandem breaker.

For this reason, I would not suggest putting the lights to a given area on breaker and receptacles on the other side. This could leave you in the dark should the receptacle side trip and the heat from the trip causing the light side to also trip. (hope that made sense :confused2

 

[ducks13]

FYI, a ground wire is not requried to detect a ground fault. Ground fault protection works by comparing the current on the phase conductor vs. the current on the neutral conductor, the should be the same; if not then there must be a ground fault.

 

[JRobyn]

Good info, Ducks! Those are exactly the curves I remembered seeing. I did not realize until I studied those a bit that the "instantaneous" trip current is SEVEN TIMES the breaker rated current!

- Jay

 

[dex3361]

I am an electrician and we rate our circuits for 80% of breaker value. For instance a 20 amp breaker should only carry 16 amps under continuous load (calculated load). This works great for commercial operations where motor loads are known, but its hit and miss in residential applications. I have seen many a breaker that is marked 20 amps and pulling a continuous 23 amps without tripping. Ive seen it many times over the years. It shouldn't do it but it does. Remember, #12 wire is ACTUALLY rated to conduct 30 amps of power, but by convention its rated at 20 amps. So the 23 amps wont cause a fire per say. Now as to why it didn't trip with a short to ground tells me either the ground wire wasn't connected completely thru to the panel, or that particular breaker is toast.

I have never been asked in over 30 years to test someones breakers.....not sure how to effectively do that even. If there is a question, i simply replace it. I still remember the old advertising for Zinsco brand breakers...." Our breakers are so tough....they never trip" thats cause they were cra*.

I have not installed a powered attic vent for many many years. I have never seen one that has shorted out though. I'm sure it can happen.

QO breakers are rated very highly in our industry, but i am very skeptical about the twin (mini) breakers. I don't see how they can be as effective as the full sized breakers.

A ground fault or an ark fault breaker could add further protection to this fan in the future. HOWEVER you need to make sure the ground wire is intact all the way into the panel.

Current testing residential circut breakers is not something you normally do.
That said it is a test performed in the industrial environment. Here is a link to a Breaker Tester.

 

[Tollster]

It never hurst to throw them manually once or twice a year, but never physically tested them.

 

[MillWeld]

It has been about 3 weeks since I replaced the motor on the attic fan and although it has been too cold for the fan to come on the GFI circuit this motor is on has not tripped the breaker. The old motor definately had a short between hot and ground (and fortunately the new one did not - duh) - measured them both.
Bob

 

[MillWeld]

FYI, a ground wire is not requried to detect a ground fault. Ground fault protection works by comparing the current on the phase conductor vs. the current on the neutral conductor, the should be the same; if not then there must be a ground fault.

I did not know that:thumbsup: Thanks for the info. (Actually, Charlotte is my home town).

 

[972500]

Any thoughts that the bearing could be seized because of a electrical short? happens in cars a fair bit, I believe it was early camarys went through wheel bearings all the time and come to find out the engine ground strap would break and the bearing was the next easiest ground. Just a thought
Mark

 

[MillWeld]

Any thoughts that the bearing could be seized because of a electrical short?Mark

Could be. The motor shaft was fairly difficult to turn by hand. It's in the trash now.
Bob

 

[ray66v]

Anyone who does not think there is a difference in QO breakers is mistaken. I have 3 panels here full of them, and they are without a doubt, more sensitive than anything else I have come across.

You may not notice the difference unless you inadvertently find a way to test them, as I did. I have a hand grinder that uses 1800 watts @ 115 vac. I have plugged this grinder into 20 amp circuits on boxes with; Cutler-Hammer, GE, Siemens, Bryant, and Homeline, breakers. And it does not trip them. I have also used it on jobs with FP breakers, but since lightning won't trip them, it wouldn't matter. However, on a 20 amp QO breaker, it will trip almost every time on start up, due to the surge. The same thing happens with all my other high current items like my big radial arm saw.

I went to QO hy-mag breakers on these circuits at home, which are made to buffer this out, (they work great). And, I carry one with me if I need to install it in someones QO panel. Luckily for me, but not them, not many people have them around here.

 

[grsthegreat]

Anyone who does not think there is a difference in QO breakers is mistaken. I have 3 panels here full of them, and they are without a doubt, more sensitive than anything else I have come across.

You may not notice the difference unless you inadvertently find a way to test them, as I did. I have a hand grinder that uses 1800 watts @ 115 vac. I have plugged this grinder into 20 amp circuits on boxes with; Cutler-Hammer, GE, Siemens, Bryant, and Homeline, breakers. And it does not trip them. I have also used it on jobs with FP breakers, but since lightning won't trip them, it wouldn't matter. However, on a 20 amp QO breaker, it will trip almost every time on start up, due to the surge. The same thing happens with all my other high current items like my big radial arm saw.

I went to QO hy-mag breakers on these circuits at home, which are made to buffer this out, (they work great). And, I carry one with me if I need to install it in someones QO panel. Luckily for me, but not them, not many people have them around here.

They are a great breaker, but so $$$ that no one wants to use them in new consturction. Almost 2x the price of others.

 

[BobRip]

Now I am tempted to install a GFCI breaker on my attic fans. That's pretty easy. Is it enough? I am tempted to also put a separate fuse on each fan. I have four. Any thoughts on this?

 

[ducks13]

If I were going to be changing out breakers to make my home safer from electrical fires I would be using arc-fault breakers, not gfci's. That is what current code requires in most areas of the house. GFCI's purpose is to prevent electrocution.

Fuses might be good supplementary overcurrent portection for you fans. If you size them close enough to the actual load the do fairly well on overloads I believe.

 

[Treemonkey1000]

You shouldn't need fuses really with the breakers inline.

 

[grsthegreat]

don't get me started with ark fault breakers. they are going to be the downfall of civilization as i know it.

The ones i put in bedrooms trip constantly....doesnt matter the brand. If you get some static build up from your carpet and happen to ground out on the coverplate screw of the switch...bammo, your in the dark. Ive actually had some clients threaten to sue me if i wouldn't get rid of those breakers. I had to get a letter from state inspector forbidding me from their removal to placate these people.

Come next January nearly the entire house has to be ark fault protected...so wo behold everyone. Plus 30 breakers at $40/each will add aprox $1,200 to the wiring cost of the houses i generally wire. Waste

 

[BobRip]

If I were going to be changing out breakers to make my home safer from electrical fires I would be using arc-fault breakers, not gfci's. That is what current code requires in most areas of the house. GFCI's purpose is to prevent electrocution.

Fuses might be good supplementary overcurrent portection for you fans. If you size them close enough to the actual load the do fairly well on overloads I believe.

Sizing the fuses close to fan rated current was my thought. As stated before circuit breakers are sized to protect house wiring against fire. I am not sure arc fault would be better here, but would not hurt. If I used a 5 amp slow blow fuse on each fan, which is rated at four amps, I think that would be optimal. Am I being too paranoid?

 

[BobRip]

You shouldn't need fuses really with the breakers inline.

Why do you think a 20 amp breaker will protect a 4 amp fan?

 

[BobRip]

don't get me started with ark fault breakers. they are going to be the downfall of civilization as i know it.

The ones i put in bedrooms trip constantly....doesnt matter the brand. If you get some static build up from your carpet and happen to ground out on the coverplate screw of the switch...bammo, your in the dark. Ive actually had some clients threaten to sue me if i wouldn't get rid of those breakers. I had to get a letter from state inspector forbidding me from their removal to placate these people.

Come next January nearly the entire house has to be ark fault protected...so wo behold everyone. Plus 30 breakers at $40/each will add aprox $1,200 to the wiring cost of the houses i generally wire. Waste

I have no experience with these. It does not sound good. From theory these are electrical noise detectors. Static is electrical noise, so your comments make sense. GFCI it is.

 

[Treemonkey1000]

Are you going to fuse every cotton picking item on a circuit because it's on a 15 or 20 amp breaker? If the fan shorts it trips the breaker. That's if it shorts enough to pull the breaker all by itself. If any other load on that branch is on at the same time you are getting closer to the trip point..Some of those fans already have thermal shutouts on them.

 

[BobRip]

Are you going to fuse every cotton picking item on a circuit because it's on a 15 or 20 amp breaker? If the fan shorts it trips the breaker. That's if it shorts enough to pull the breaker all by itself. If any other load on that branch is on at the same time you are getting closer to the trip point..Some of those fans already have thermal shutouts on them.

Good Point. I have thought of the absurdity myself. The fans appear to have thermal overloads. Most devices today have internal fuses. In the past they did not. My concern with the fans is that they run unsupervised. The bearings could go bad and I might not notice. All of the other equipment I can hear, see, and smell. Yes I am paranoid, but am I paranoid enough? I am still open to suggestions. The fact that a fire department saw two fires in a year scares me. I could just do the GFCI and go with 15 amp ones. The fans are the only thing on the breakers. I over wired this house when I built it.

The code changes all the time. Most code changes are driven by some issue. Have we found and solved all of these issues? Probably not. Anyway yours and others suggestions are appreciated.