On 7/12/2017 8:38 AM, wrote:
On Tue, 11 Jul 2017 23:50:44 -0700 (PDT), trader_4
wrote:

On Tuesday, July 11, 2017 at 11:57:41 PM UTC-4, wrote:
On Wed, 12 Jul 2017 09:23:25 +0630, Lenny Jacobs
wrote:

On 11/07/2017 08:53, wrote:
On Tue, 11 Jul 2017 08:09:58 +0630, Lenny Jacobs
wrote:

On 11/07/2017 00:55, wrote:


Because it is an RCD. (30ma GFCI for you Americans)
Fix your water infiltration problem on the outside circuit.


No. They are regular breakers. GFCI breakers have a test button. Mine don't.

Are you sure your main is not an RCD? Is there a reset button? (The
RCDs I have seen don't have a test button) You say 63a and that
immediately says this is not the US because we do not have 63a
breakers here. I thought most countries with 220v used RCDs.

New Zealand
http://gfretwell.com/ftp/New%20Zeala...i/Breakers.jpg

I have uploaded two photos of the main breaker box. Please see:

https://www.pexels.com/photo/486475/
https://www.pexels.com/photo/486476/

Yes. You are right. One has a test button which doesn't work. I pressed
it. The breaker wasn't tripped.

The closer I look at the main breaker box, the more confusion I get. At
first, when I saw four breakers surrounding a main breaker, I assume
they are parallel. But now, when I look at the cable connection, it
seems to me the two Ground FL breakers are in serial, same for the other
two First FL breakers.

I don't know why a 63A breaker is connected to another 63A breaker in
serial.


The ones with 4 wires are RCDs

That's what I was thinking too. The bottom two have a 4th wire marked "N". A neutral going through a breaker would seem to indicate it's an RCD/gfci type breaker. Still don't understand all that's there, ie why there are series breakers, why there are 3 hots, etc. But agree that it's RCD and wet wires, not overload that are causing the trips.

3 phase. It is not unusual on large services out there in 220v land


(Nice call on RCD.)

------------------------
One of the important questions about an electric power system is how it
handles a hot-to-ground short - a ground fault.

In the US the fault current is carried on the ground system to the
service where it goes across the required neutral-ground bond to the
service neutral and back to the supply transformer. This is an all-metal
path that can supply the high current to trip a breaker. An earth
connection is not allowed to be used because it can not reliably carry a
high current. (What is the current if you connect 120V to a ground rod
that is a code-compliant 25 ohms-to-earth?)

In parts of the UK the neutral is earthed at the supply transformer but
not elsewhere. There is no N-G bond at the building. That means the
fault current return is through the earth, which will not reliably trip
a breaker. I think that is why RCD main-breakers are used - the earth
fault return current will trip an RCD. That may be why this system has
RCDs. The only number I have seen for an RCD trip is 30 mA. That seems
like it would be subject to nuisance trips. It is also the number I have
seen for RCDs protecting people - seems too close to the can't-let-go
current.

In the US, as most of us know, GFCIs to protect people trip at 5 mA.
There are GFIs to protect equipment that trip at 30 mA. And AFCIs
include a ground fault trip, I think always at 50 mA.

-------------------------------
The pictures show devices in series. Likely the top unit is an ordinary
over-current breaker and the bottom one is only an RCD.

Likely a large main breaker in the center (that is how it is marked),
fed from the bottom, feeding 2 - RCD-protected feeders.

------------------------------
A 63 A (67?) 220V 3 ph feed is equivalent to about a 190 A split-phase
service here.

------------------------------
Would be a good idea for the OP to google the breaker information to
find specs and instructions.

-----------------------------
As a warning - the service may only be about 150 A. But a short on the
service wires before the breaker can have a current of thousands of amps
- would be very unpleasant.

------------------------------
And this newsgroup is mostly US, though we humor some foreigners from
north of the border. Happy to answer questions, but would have helped
for the OP to say he is in Thailand, especially on a question like this.