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.