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
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
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.
On Monday, July 10, 2017 at 9:16:55 PM UTC-4, Lenny Jacobs wrote:
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?
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.
On Monday, July 10, 2017 at 1:18:30 PM UTC-4, firstname.lastname@example.org wrote:
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?
On 11/07/2017 03:47, email@example.com 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.
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
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.
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.
On Tuesday, July 11, 2017 at 2:09:00 AM UTC-4, firstname.lastname@example.org 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.
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.
On Tuesday, July 11, 2017 at 11:35:25 AM UTC-4, email@example.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?
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.
On 12/07/2017 08:54, firstname.lastname@example.org 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.
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?
On 13/07/2017 03:57, email@example.com 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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