breaker response time

On Monday, July 10, 2017 at 12:14:36 PM UTC-4, Lenny Jacobs wrote:

How do you identify which one caused it? Does it immediately trip the main again when you put the offending breaker on, ie the fault is still there? If so, if it's not intermittent, I would think you'd immediately further track down what the source of the fault is.

Do you really mean tripping or that it's something on that 63A breaker that causes the main to trip? You said the main was tripping, not the other breaker. Also this picture is different than what I think most of us were envisioning, which was a typical main panel with individual branch circuits, not a main that feeds what appears to be two subpanels, That shouldn't really matter though.
What do you believe the total load normal load on it is, just before it trips? What's going on at the subpanels when this happens, those 63A breakers must feed subpanels of some kind. Anything tripped there? As to why the 75A trips first, it makes more sense now. Breakers have curves as to how fast they trip versus the size of the fault. Different breakers will have different curves and they are not exact. What you have is a 63A breaker and a 75A both exposed to an overload. Additionally, you don't tell us what else is on that main panel besides the two 63A breakers, but if there are other circuits, then the 75A is seeing whatever the 63A one is, plus those other loads. With other loads, no surprise it trips first. Even without other loads, if you present a major over load to both, the 75A might trip first if it's curve is slightly different.
I think most of us were envisioning that you had a big main breaker, eg 150A and then smaller breakers, eg 20A that feed those other circuits.

Where are you? We were assuming this is US.
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On 10/07/2017 23:01, trader_4 wrote:

I flipped all sub breakers down and flipped them one by one to locate the offending breaker. Once I found the offending breaker, I left it down and everything would be fine. Well, except that particular circuit that was turned off.

Sorry for the confusion. I had not known the system was this complex before I checked it. There are two panes. One contains a main 75A breaker with four 63 A sub-main breakers. Before, I had been saying "main breaker". It turned out to be a 63A sub-main breaker.
There is another panel containing about 50 breakers (actually, this panel has two chambers, one containing 50 or so breakers, the other empty). There are no more panels.

I would think main breakers would have a slightly longer response time so to give time to sub breakers to trip.

Thailand.
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On Monday, July 10, 2017 at 9:16:55 PM UTC-4, Lenny Jacobs wrote:

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Gfre has brought up a few times now that you may have a main breaker that d oesn't just trip on overload, but one that also trips if there is even a ti ny ground fault. A ground fault is current flowing to ground instead of con fined to the conductors. In the USA they are called GFCI breakers. Gfre s ays in Europe they are called RCD. If that's the case, then a current of j ust 30ma can trip it and you can get that from wet connections, outlets, et c. It's very common. Does that main breaker have anything that makes it l ook different? Markings? A test button?
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On Mon, 10 Jul 2017 22:44:27 +0630, Lenny Jacobs

Then replace the damned things, they are not doing their job. There is NO WAY the main should kick before the branch circuit protection

OK - Euro system. Different problems. No "load balance" issues. 2 "main breakers" in the building. One never trips. The other trips when it is wet outside. You have external lighting circuits on that main. You most likely have leakage in those 2 circuits, not enough to trip the branch breakers, but enough to load the main heavily enough that the rest of the loads, combined with the circuit leakage, overloads the main. Find out what is on the circuits in question and get those circuits checked and fixed - or permanently disconnected.
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On Monday, July 10, 2017 at 1:18:30 PM UTC-4, snipped-for-privacy@snyder.on.ca wrote:

This.
But just for completeness, breakers go open for three reasons that I know of, probably more.
You turn them off. They can stand a lot of this. Some are rated to be used this way, but even nonrated ones can do a lot of cycles.
They overload slightly. They can do a lot of these cycles too, but not nearly as many before getting too sensitive or failing. I think it's a factor of 10.
They see a dead short. This is bad. They're only rated to do that twice, and sometimes once is enough. That's okay, they did the job and kept your house from burning down, but now you need a new one.
Rainy weather is probably an overload rather than a dead short. Who knows?
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wrote:

Fine line between a heavy overload and a dead short. If the main is tripping and the branch is not, you can be pretty sure it is NOT a dead short on one of the branch circuits - - - -
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On 11/07/2017 03:47, snipped-for-privacy@snyder.on.ca wrote:

Good assumption. But in my case, when I turned off all breakers and flipped them one by one to locate the offending breaker, I always found one breaker (different ones on different occasions, a total of four breakers) that, when flipped, would trip the sub-main breaker.
Also, as I stated in another post, I have a total of 10 lights, three refrigerators, a water heater, and some small gadgets such as TV, DVD player, etc. There is no way they would overload a 63A, 220 V breaker.
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On Tue, 11 Jul 2017 08:08:19 +0630, Lenny Jacobs

What is the rating of the branch circuit breakers?
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On Monday, July 10, 2017 at 9:38:25 PM UTC-4, Lenny Jacobs wrote:

In an earlier post you said that the only difference you see when the offending breaker is off are the garden lights. Now you say that it it is "different ones on different occasions, a total of four breakers".
Does that mean that you have 4 breakers for the garden lights and that any (and only) one of them might be the offending one at any given time? 10 lights on 4 different circuits and the problems move from circuit to circuit?
If so, then that means that only 1 of the 4 circuits is getting wet at a time, which is really strange. It also means that all 4 circuits have some type of moisture issue, which is also kind of strange - unless the fixtures are crappy and/or the person who did the original wiring screwed up all 4 circuits.

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On 11/07/2017 09:38, DerbyDad03 wrote:

Since garden lights are not working, one of the four must be responsible for them. I have no clue what the other three breakers are for.
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On Tue, 11 Jul 2017 10:50:24 +0630, Lenny Jacobs

Since you seem to have isolated it to moisture problems in your garden lights, I would see if you can see where the water is getting in and seal them up. We have a lot of that type of thing here in Florida. I have found you want to open the wiring compartments, get all of the wires centered in the box is best you can so they are not touching the sides and pointing up so water tends to drain out of the connections.
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On Tuesday, July 11, 2017 at 2:09:00 AM UTC-4, snipped-for-privacy@aol.com wrote:

I no longer think that's the case. Now he says that only 1 of the 4 possible breakers that needs to be left off is for the garden lights. He doesn't know what the other 3 are for. That tells me that when any 1 of the other 3 breakers are left off, something(s) isn't working, but he has no idea what.
Seems to me that he might as well just leave those other 3 breakers off all of the time since they apparently have no impact on his life. *Then* he can fix the garden lights and never have a problem again.
Did he really say that he has over 50 breakers and no real clue what any of them (other than the garden light one) do? Holy crap.

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On Tue, 11 Jul 2017 03:56:18 -0700 (PDT), DerbyDad03

He also says it happens when it rains. One thing I learned as an inspector is when a guy makes a mistake installing stuff, he does it a lot. With 50 circuits, there is a real good chance 4 of them feed wet location loads. I have a typical US service and I have at least half dozen circuits with an outdoor load.

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On Tuesday, July 11, 2017 at 11:35:25 AM UTC-4, snipped-for-privacy@aol.com wrote:

I agree except that it's pretty strange that he says that it can be any 1 of 4 circuits that cause the main to trip, yet he only sees one that makes a difference - the one for the lights. Whatever "load" is getting wet on the other 3 is not known to him. The only thing I can think of is receptacles that he doesn't use and perhaps has not located. Testing them would be pretty easy once he locates them.
It's also strange that - if I understand his explanation correctly - it's always only *1* of the 4 at any given time. With 4 possible circuits that can - and apparently do - get wet and cause the problem, why would it always be just a random 1 of them that causes the problem at any given time? Is the rain in Thailand selective?
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On Tue, 11 Jul 2017 18:51:13 -0700 (PDT), DerbyDad03

My "suspicion" is any one , or possibly combination of 2, would cause the problem. Still don't know exactly what amperage the branch breakers are, but he has a 63 amp "sub-main" that trips. If he has 7.5 amp breakers (equivalent to 15 amp 120 volt) and he has 25 running an average of 1/4 capacity, that is 46.875 amps. Say the other 4 are at 6 amps each, the main may trip,(70 amps) while shutting any 1 off may keep it from tripping at 64. The "short" resistance in the 4 may not be exactly the same - one may draw heavier than the other on a given day (it IS a "random" fault) - so shutting all 4 off, then turning the others on, it may be different combinations that work from day to day.
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On 12/07/2017 08:54, snipped-for-privacy@snyder.on.ca wrote:

Well, I have about 10 lights, one water heater (about 30 gallon), one ceiling fan, three refrigerators. When I turned on TV/DVD, used a kettle, turned on A/C, used the range in the kitchen, the breaker was not tripped. It would take a lot more than these to overload a 63A breaker.
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On Wed, 12 Jul 2017 10:23:24 +0630, Lenny Jacobs

You have NO IDEA what amperage the other 4 (that cause the trip) are drawing. What is the rating of the branch circuit breakers? The water heater is likely 30 amps, the range is likely 40 amps (if it's all turned on). That is already more than 63 amps!!! If the range is off, it draws nothing, of course - but you do not indicate if it is in use. The fridges could be drawing 3.5 amps each - perhaps 7 when starting, and about the same when running the auto defrost cycle. When it kicked the kettle wa not in use? Or the AC? Were the lights on? With everything else turned off, can you turn on the 4 "bad" breakers without tripping the main?
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On 13/07/2017 03:57, snipped-for-privacy@snyder.on.ca wrote:

Can't tell the rating of most of the breakers. The electrician who installed them did a great job labeling every one of them. The label sticker is right on the rating. Judging from the size of the breakers, they could be 13, 16, or 20 A.
My point of mentioning A/C, range, etc. was that besides those constantly on appliances, the breaker was not tripped when A/C or range was turned on. The breaker was tripped when A/C or range was not on. So, it kind of excludes overloading.
Now it turns out that the tripped sub-main breaker is a GFCI, a wet circuit is almost certain the cause of the problem.
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On Thu, 13 Jul 2017 07:04:53 +0630, Lenny Jacobs

In a euro 240 style system I highly doubt most are over 7.5 amps.

\Being the sub-mains which are being tripped are GFCI breakers, you can bet the farm on it. No idea why they have such a ludicrous system - the branch circuits should be GFCI protected.
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On 13/07/2017 09:33, snipped-for-privacy@snyder.on.ca wrote:

I just checked eBay. The price is still around $50 a piece.
Maybe I should replace those four problematic breakers with GFCI, beside replacing the sub-main breaker.
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