SAFE-T-CUT TRIPPING DAILY

[lopburi3]

If you have to buy a new main power panel you can still make use of the one you have (as you seem to be using all breakers now) and that would give you more circuits.  I have 4 power panels in my house (built in 1975 so many updates and extensions- one panel just for kitchens).

[livram]

11 minutes ago, lopburi3 said:

Can't remember but you mention one AC always on 24 hours a day.  Have you been able to trip breaker if that one AC is turned off and everything else on?  If breaker not bad there must be something drawing more power than expected.

Will do this Monday AM when PEA tech arrives.

[bankruatsteve]

Is there a potential for the mains N to have a fault to the structure whereby it just doesn't kick in until the amps go up at which point the fault will bring on an overload?  

[sometimewoodworker]

2 minutes ago, bankruatsteve said:

Is there a potential for the mains N to have a fault to the structure whereby it just doesn't kick in until the amps go up at which point the fault will bring on an overload?  

The indicator was not red with the overload trip that was just tested, so not very likely as that should do a line/neutral/red indicator trip.

[VocalNeal]

A new breaker is 530 baht! From Safe-T-Cut 

https://www.safe-t-cut.com/en/product/mcb-3p-eu/

 

problem quartered?

Just saying...

 

If OP is in an urban place they might even come and fit it?

Edited April 11, 2020 by VocalNeal

[bankruatsteve]

1 minute ago, sometimewoodworker said:

The indicator was not red with the overload trip that was just tested, so not very likely as that should do a line/neutral/red indicator trip.

The RCBO would not detect a fault in the mains.  ????

[sometimewoodworker]

5 minutes ago, bankruatsteve said:

The RCBO would not detect a fault in the mains.  ????

I’m not at all clear the possible problem you are suggesting.

[VocalNeal]

The newest addition is the 12,000 AC? 

 

With it OFF and everything else ON

 

Put your new clamp meter of each of the wires under each of the breakers and note the readings. 

Total them up.

Then turn on the 12000 AC. 

repeat to find the extra.

Edited April 11, 2020 by VocalNeal

[lopburi3]

12 minutes ago, sometimewoodworker said:

I’m not at all clear the possible problem you are suggesting.

Believe it might be a hot touching neutral short he is talking about as that would not be an imbalance and could easily draw high amperage.  Had it happen a few times from rat eating wire so they touched together, trip circuit breaker, reset fine for awhile until next time.

[Metropolitian]

44 minutes ago, livram said:

Eyes returned. Looked thru hole with torch and when I pushed test button elec tripped and hole showed RED. Then I ran all a/c plus shower heater etc, after 5 minutes 3-gang breaker trip but no change or movement on indicator hole, just stayed gray.

The current leaking probability is eliminated ????

 

Now we can focus on the overload part.

Member Livram is not able to do more test and measuring until PEA and/or Helper is there.

 

Meanwhile we, the sparkies here, can setup a 'list' of possibilities.

 

Mine:

• The wiring is too small for carrying high currents, resistance goes up and voltage drops at the end of the line making the appliances demanding higher currents and current is everywhere the same on the group.  All breakers are carrying the current but the mainbreaker collapse.
  (Wish we knew the current going to the main incoming wires in the CU. We would know if the currents reach 80amp or above)
• The A/C compressors are working harder, maybe low on cooling agent and the compressors are starting more often with prolonged peak surges, remember it's a B-curve breaker. It is not unbeknownst that some older aircon use more amp (ex. 4000watt for a 12kbtu unit) after a few minutes when the meager gas returns to the outdoor unit
  (I had one which got to the 25amp for a 9kbtu unit, tripping the 20amp breaker, in the last week of its life)
• Faulty 'main'breaker, when current comes near the 50amp it trips instead of the rated 63amp (Which can carry +25% extra for a short time)
• ....(add yours)

[VocalNeal]

Dear OP,

 

How much was your last electricity bill? From that we should be able to back calculate and estimate how much current you actually draw. Not peak I agree but...

[Metropolitian]

31 minutes ago, VocalNeal said:

A new breaker is 530 baht! From Safe-T-Cut 

https://www.safe-t-cut.com/en/product/mcb-3p-eu/

That is only a 3phase breaker , MCB 3p.

 

The OP, if the main breaker is faulty then need the RMD 9 as replacement, which is 2p with RCBO.

A whole in one unit.

https://www.safe-t-cut.com/product/rmd-9-png/

 

Pricetag 1450b-1800b

[bankruatsteve]

25 minutes ago, sometimewoodworker said:

I’m not at all clear the possible problem you are suggesting.

Well, it was a question, not a suggestion.  I'm thinking that IF it's not a faulty breaker and seems to be no faults in the circuits, then MAYBE it's a fault in the mains that only kicks in when the amps are up?  Not something likely to happen in the states or with MEN so just wondering if that would be a likely scenario here?

[Crossy]

For those wondering what-the-flip we are talking about when we refer to MCB "curves", this may (or may not) clarify.

 

 

 

The bit labelled B, C or D (A curve are very rare) is the "instantaneous" trip area usually a magnetic system, the rest of the curve is the "thermal" curve. With our OP having trips in the minutes it sounds thermal.

 

We will know more once we have some measurements.

[KMartinHandyman]

1 hour ago, Crossy said:

 

Main breaker says "B63" = 63A.

 

Is it possible the thermal aspect of the thermal-magnetic breaker is doing its job? He says it essentially happens a few minutes after he puts the panel under the full house load. Possibly undersized wire size or distance resistance somewhere generating heat at the main breaker. 
63 amp is enough and the constant 2 and 3 minute time delay is the tell versus instantaneous opening would be my guess, emphasis guess.  

Or it’s just faulty as you say!

Edited April 11, 2020 by KMartinHandyman
Adding faulty as Crossy says

[Metropolitian]

10 minutes ago, Crossy said:

(A curve are very rare)

Very rare indeed ???? Know of BCDKZ with Z coming near to the A curve.

An 'RCB' with A and Z curve I would compare that to those mini breakers used at the appliance sides.

In fact I see them on my UPS and a few extension sockets do have them.

 

I will throw in a curve table, as some of us do like them ????

 

[livram]

40 minutes ago, VocalNeal said:

Dear OP,

 

How much was your last electricity bill? From that we should be able to back calculate and estimate how much current you actually draw. Not peak I agree but...

Last bill for March was 5105 Baht consumption 1150 units, Feb 925 units Jan 858 units Dec 720 units Nov 927 Oct 1013 and Sep 920 Units

[Metropolitian]

17 minutes ago, livram said:

Last bill for March was 5105 Baht consumption 1150 units, Feb 925 units Jan 858 units Dec 720 units Nov 927 Oct 1013 and Sep 920 Units

About 1.35 unit per hour continuously will be around the 1000 for one month. Pretty much one A/C running 24/7.

 

[sometimewoodworker]

1 hour ago, VocalNeal said:

Dear OP,

 

How much was your last electricity bill? From that we should be able to back calculate and estimate how much current you actually draw. Not peak I agree but...

It’s in a post, over ฿5,000 so as the AC loads are 24h too low for a general overload, IF everything is working as it should, which it clearly is not

[VocalNeal]

Noting something mentioned in a different thread 12,000 AC about 5.5 amps but standby generator struggles to start but handles 23,000 inverter (soft start) unit. 

 

Could be our tripping breaker is because of inrush from starting AC? Difficult to quantify, maybe?

[VocalNeal]

Is it fixed yet?

[livram]

11 hours ago, VocalNeal said:

Is it fixed yet?

No. Long story short I started taking measurements with Son_In_Law  and daughter using phone. I got a few measurements but mostly phone chatter consisted of "really hot out here" "Is he finished yet" yet. Also I discovered that I didn't know how to take VOLTAGE measurements using multimeter ant the meter and at the CU. So decided that best to wait for PEA tech to come Monday after he rescheduled from Sunday. When he didn't show Monday noon, we called and was informed he would not be coming because "It is Songran". He lives here in this tiny village and there is absolutely nothing going on. So I will wait until next week and go to PEA to see if I can hire a sparky who wants to work.

 

During our shutdown the water pump quit completely which is a disaster here as the water is off via the village most of the time and when running the water pressure is pathetic. The good news is that after several hours discovered that black ants were the problem. Luckily I had a spare "pressure switch" that I swapped out and now pump works perfectly. All credit to SIL who redeemed himself.

 

I even thought that fixing water pump must have solved my problem of breaker tripping but it was not to be.Running 3 A/C's and switching shower heater, microwave, rice cooker, or water pump usually trips breaker.

 

Here are some numbers:

 

12K A/C only 5.40

18K a/c only 5.20

9.2 a/c plus lights, TV box TV etc 7.10

 

Amp clamp at meter running 3 a/c lights, pc etc 15.2 Amps

 

Amp clamp at meter running all of the above and then turning on shower heater plus water pump - 31.3 Amps - runs 2 -3 minutes then trips.

[Metropolitian]

2 hours ago, livram said:

Amp clamp at meter running 3 a/c lights, pc etc 15.2 Amps

Amp clamp at meter running all of the above and then turning on shower heater plus water pump - 31.3 Amps - runs 2 -3 minutes then trips.

This is the most important measuring numbers we wanted to know.

 

My answer will be: The mainbreaker is faulty. Replace.

 

[Crossy]

6 hours ago, Metropolitian said:

This is the most important measuring numbers we wanted to know.

My answer will be: The mainbreaker is faulty. Replace.

 

Yup, that would be my conclusion too.

 

Unfortunately the only way to be sure is to replace it. Testing an MCB is well outside the scope of DIY.

 

[sometimewoodworker]

6 hours ago, Metropolitian said:

9 hours ago, livram said:

Amp clamp at meter running 3 a/c lights, pc etc 15.2 Amps

Amp clamp at meter running all of the above and then turning on shower heater plus water pump - 31.3 Amps - runs 2 -3 minutes then trips.

This is the most important measuring numbers we wanted to know.

 

My answer will be: The mainbreaker is faulty. Replace.

Absolutely as 32A will be the trip current for a 20A or 25A breaker 

 

your 63A should not trip on current below about 75A to 80A in the time you give.

[sometimewoodworker]

2 hours ago, sometimewoodworker said:

Absolutely as 32A will be the trip current for a 20A or 25A breaker 

 

your 63A should not trip on current below about 75A to 80A in the time you give.

Further to that. Just because you have found 1 problem does not mean that you have found all the faults.

 

You still need to get all the figures that @Crossy listed, I don’t remember if that included the size of the cables feeding from the meter but you need to check/take a clear picture so we can check for you.

 

you may well find that everything else is OK but you can’t be certain.

 

[tifino]

5 minutes ago, sometimewoodworker said:

Further to that. Just because you have found 1 problem does not mean that you have found all the faults.

 

yes... have already seen it happen; that after any/all sources to cause the original trippings had been eliminated

- the RCB that copped having to do all that tripping, is itself longlife compromised.

[livram]

1 hour ago, sometimewoodworker said:

 

 

You still need to get all the figures that @Crossy listed, I don’t remember if that included the size of the cables feeding from the meter but you need to check/take a clear picture so we can check for you.

SIL said only numbers he could read at on meter cable are "600 volt" "2X6" and "064/2558". All meters were moved from 4 meter poles to 8 meter poles about 3 months ago. Then last Friday a team from PEA came to check meter and said that they moved the meter connection fro supply line 1 as #1 had too many connections. to supply line 2. But it made no difference.

[sometimewoodworker]

2 hours ago, livram said:

SIL said only numbers he could read at on meter cable are "600 volt" "2X6" and "064/2558". All meters were moved from 4 meter poles to 8 meter poles about 3 months ago. Then last Friday a team from PEA came to check meter and said that they moved the meter connection fro supply line 1 as #1 had too many connections. to supply line 2. But it made no difference.

The picture you posted 

does not seem to agree with that statement 

 

the possibility from your numbers  (I don’t want to raise this as a problem without actually seeing if it’s true) is that you may have a 6mm² feed. If that is the case then your cables are grossly undersized as they should probably be 16mm copper and bigger if aluminium.

 

that is why a clear picture will probably decide if your SIL has made an error or not.

 

6mm would be an OK size for a 5/15 meter, your meter may have been upgraded without upgrading the supply cables to the house.

Edited April 15, 2020 by sometimewoodworker

[Metropolitian]

38 minutes ago, sometimewoodworker said:

The picture you posted 

does not seem to agree with that statement 

 

the possibility from your numbers  (I don’t want to raise this as a problem without actually seeing if it’s true) is that you may have a 6mm² feed. If that is the case then your cables are grossly undersized as they should probably be 16mm copper and bigger if aluminium.

 

that is why a clear picture will probably decide if your SIL has made an error or not.

 

6mm would be an OK size for a 5/15 meter, your meter may have been upgraded without upgrading the supply cables to the house.

 

 

On top of that, the blurry picture shows the cables from the utility lines to the meter. 

The consumer cable is on the right side of the meter.