Circuit Breaker Finder

[Cecil]

I just purchased the Extech CB10.  I followed the instructions.  Not only does it not find the breaker, it blows the main.

I plugged in the sending unit.  I has LED indicators to tell you the receptacle status, i.e. wired correctly, no ground, hot, ground reversed, etc.  That seemed to work.

I went to the breaker box but it did not narrow in on a breaker.  It somewhat indicated one of two.  I switched them both off, one at a time.  It was not either one.  It was one lower that the two.

Here is the kicker.  I left the sending unit plugged in and reset the breaker.  The main popped.  I could not reset the main until I pulled the sending unit.  Neither the sending unit, nor the receptacle were not.  I repeated this on a second circuit.  The box uses pushmatic breakers.  Previously I borrowed a friends "Ideal" circuit breaker finder.  It also would only get close, but it did not blow the main breaker.

I never blew the main before.  In fact, I have not blown a single breaker in the year I have been here.  The only electrical work I have done on the house is to replace the outside receptacles with outdoor rated GFCI units.

I went to the garage, which has its own 100 amp service.  I quickly found the correct breaker.  The main did not blow.  The garage uses Square [D].

What gives.

Thanks.

[Snipe Hunter]

Any possibility you have a faulty main breaker?

[Cecil]

(01-07-2018, 07:30 PM)Snipe Hunter Wrote: Any possibility you have a faulty main breaker?

It is possible.  However, why would it be fine with other load, and greater loads.  Why only with the scenario described above.  If I turn off breakers and turn them back on with other live equipment plugged in, the main does not trip.

Pushmatics are obsolete.  The home inspector, also a contractor, whom I know and trust, warned me about the fact they were obsolete, but he did not see any reason to replace it.  He did inspect a house for me, which had Federal Stab breakers.  He recommended immediate replacement of those.  I backed out of that deal.

I don't know how to determine if a breaker is faulty.  I will have to have an electrician look at it.  I will talk to one tomorrow, but it will be a bit before I have one come and look.

[daddo]

What sized main breaker? If you shut down running loads and right back on, the initial inrush may trip a breaker.
Examples would be appliances, Heat pump system, all running and short cycled- then include lights, TV, cable boxes and so on.
Then sometimes the breaker just doesn't catch right and isn't tripped, just not completely set. This could also indicate a failing breaker that has tripped a few times.

Could be the meter alone tripped it on top of other loads..

[Cecil]

(01-07-2018, 09:31 PM)daddo Wrote: What sized main breaker? 
...
Could be the meter alone tripped it on top of other loads..

I just did some research on Circuit Breaker Finders and they state that they draw quick bursts of 6-10 Amps.  I did not realize they pulled that much.  You could be correct.  During our cold snap, I am taxing my system, and may be near capacity.  I will turn off a couple of the electric heaters and try again.  I will try that tomorrow.

Thanks.

[Cecil]

(01-07-2018, 09:31 PM)daddo Wrote: Could be the meter alone tripped it on top of other loads..

Yep, that was it.  Turn off two Oil filled room heaters and all the lights.  The main does not trip. 

It still does not trace the circuit.  It does get me within three.  I can check out other brands, but all of them have complaints in the reviews about inaccuracy.  It worked great on the Square [D].

[MarkSingleton]

I have the Klein version of that device. What I discovered using it is that
you have to "wand" over the breakers very slowly. Had the same experience
as you, in that it would indicate several at once. After I learned to slow
the speed at which I moved it up and down the panel, it will zero in on the
correct one.

YMMV.

[cndamm]

I've always just plugged a radio (turned up loud) to find and mark the breakers when I move into a new place. It saves a lot of time when you need to turn off a circuit.

[splinter7612]

I have an older one from HD, possibly an Ideal brand and it has a sensitivity wheel on it where once you get close to the 3-4 breakers you turn down the wheel and it narrows it down to the correct one.

[Cecil]

I had an epiphany. 

To me, it makes sense the I would run the tester down the outside of the breakers.  If I run it down the center, I could not tell whether the left or right breaker is the correct breaker.

It is picking up the signal off the hot bus bar.

I run the sensor unit down the outside, to determine left or right, then I run it down the center to find vertical position.  Works like a champ.

It has to do with the box configuration.  I do not need to do this with the Square D