House ELCB Tripping Problem Solved

By on August 6, 2014
aircond starting capacitor

 

 

 

 

 

 

 

 

Recently my house main ELCB (Earth Leakage Circuit Breaker) tripped intermittently. The ELCB can trip from few minutes to an hour.  For your information there must be something that had gone wrong and drawing too much current causing the ELCB to trip.

elcb

Before I reset the ELCB switch, I removed all the electrical devices plug like handphone charger, hair dryer, TV, router and etc and also turned off all the lights. I even turned off the air-conditioner (air-cond).

 

Once done, I reset the ELCB switch and connecting back the electrical plugs one by one hoping to see the ELCB trip again. If it tripped then I know the source of the problem.  I did not turn On the air-cond. I let all the electrical devices connected to the ac socket and all the lights On for more than 2 hours and the ELCB did not trip. This is a good sign because it means the air-cond could be the problem. So I went to the living room and turn On the air-cond and within 10 minutes the ELCB tripped! I tested few more times and I confirmed indeed the air-cond was the cause of the problem.

Since I do not repair air-cond I called my friend who is a specialist in fixing and repairing air-cond. I told him about the problem. He came, took some tools and climbed up to reach the air-cond. Just within 10 minutes he showed to me a big capacitor (30uf 400v) and told me it was open circuit.

capacitor1

He said the capacitor (Compressor Motor Starting Capacitor) did not show any sign of kicking (charging/discharging) when tested it with his Sanwa analogue meter. He fixed in the new capacitor and asked me to turn On the air-cond.

aircond starting capacitor

He waited for about few minutes for the compressor motor to kick in. And when we heard the motor was running and the ELCB did not trip he tested the air-cond for few more times to really make sure it would not trip.

He explained to me saying that when the compressor motor fail to start at all (due to the bad capacitor), the motor will just hum (drawing high current) and eventually the tripping will occur. I then paid him for the job done.

capacitor2

By the way, I brought the capacitor back to my workplace and tested it with my digital capacitance meter and it showed zero capacitance value. It also showed no reading when tested with my Blue ESR meter.

capacitor

Note 1: All the high voltage capacitors need to be discharged first! High voltages which are still present inside the capacitor can give you an electrical shock which is hazardous! It can kill you! Do not try to do this on your own if you are not sure what you are doing! Do not try to repair if you are not a qualified technician or engineer.

Note 2: Be extra careful when climbing on high places to fix air-cond, antenna and etc. There are fatal cases involving repair techs falling down from high places. If you do not have confident let the professional do it.

 

jestineyongpowersupply

 

 

 

 

 

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74 Comments

  1. beh

    August 6, 2014 at 1:05 pm

    HI MR YONG
    yes this is a very good way to troubleshot the equipment of the house
    and thanks for your safety suggestions.
    beh

    Likes(4)Dislikes(0)
    • Jestine Yong

      August 6, 2014 at 1:22 pm

      Hi Beh,

      You are welcome!

      Jestine

      Likes(3)Dislikes(0)
      • kumar

        November 24, 2015 at 4:10 pm

        Hi Mr.Jestine,

        In my home, the ELCB intermediately trip so the electricity for the whole house was shut down. When i switch on the ELCB everything working fine but may be after an hour or 2/3/4 hours later again it will trip. Just i want to confirm whether i have to change the ELCB or not? When i test the elcb that means push the button it will trip, it means working fine right.

        I have other 8 small breakters but nothing happen. It means nothing problem in any individual home appliances right?

        Can you please give me your solution. According to electrician need to change the ELCB.

        Thanks
        With regards
        kumar

        Likes(4)Dislikes(0)
        • Jestine Yong

          November 27, 2015 at 9:28 am

          Hi Kumar,
          You can start to remove a device (or home appliances) one at a time to see if it still trip. If you have checked all and the ELCB still trip then you may need to change it.

          Jestine

          Likes(0)Dislikes(0)
  2. Sethu Ramachandran

    August 6, 2014 at 1:22 pm

    Thanks for this article , this blog is to be a common
    Platform for all technical issues

    Keep up the goodwork .

    Likes(0)Dislikes(0)
    • Jestine Yong

      August 6, 2014 at 1:46 pm

      HI Sethu,

      You are welcome!

      Jestine

      Likes(0)Dislikes(0)
  3. Luciano

    August 6, 2014 at 1:29 pm

    Mr. Jestine,
    This is a beautiful article. i like the methodology for tracing the faulty appliance and also your honesty and truthfulness in that you called in the person specialized in the field to do that job. Thanks so much for the two concluding points. i will take note of that now that am going up to fix the water heater in our house.
    Regards!
    Luciano

    Likes(0)Dislikes(1)
    • Jestine Yong

      August 6, 2014 at 1:46 pm

      Hi Luciano,

      You are welcome and hope you could find the problem in the water heater.

      Jestine

      Likes(1)Dislikes(0)
  4. Gopal Sharma

    August 6, 2014 at 1:32 pm

    Sir,

    There is some wiring problem in a house. Some time when there is heavy rain, then one can get shock by touching the wall. I know it is harmful but i want to know whether it is drawing extra current to increase the electricity bill or not. How can i test to make sure.

    Gopal Sharma

    Likes(0)Dislikes(0)
    • Jestine Yong

      August 6, 2014 at 3:00 pm

      Hi Gopal,

      Sorry I don't understand your question. You wanted to know if the shock in the wall will increase the electricity bill?

      Jestine

      Likes(4)Dislikes(0)
      • Gopal Sharma

        August 6, 2014 at 9:08 pm

        Shock in the house wall means it may be drawing some current through the wall. How to make sure , it is drawing some current and also any effect in electric bill or not.

        Likes(0)Dislikes(0)
        • Jestine Yong

          August 7, 2014 at 12:42 pm

          Hi Gopal,

          Sorry I do not have info on this. Perhaps you need to check with an electrician.

          Jestine

          Likes(1)Dislikes(0)
    • Lee

      August 6, 2014 at 8:39 pm

      Its current Leakage and maybe your Elcb have problem should ask a technician to check...

      Likes(0)Dislikes(0)
      • Jestine Yong

        August 7, 2014 at 12:03 pm

        Hi Lee,
        ELCB is good because after the replacement of the capacitor the aircond is working fine and no more tripping. According to Paul's comment the cap internal part could have shorted to the ground through the casing causing it to trip.

        Jestine

        Likes(1)Dislikes(0)
    • Imraz

      August 7, 2014 at 5:12 am

      Hi Mr Sharma
      Your answer on above issue is to check the ground of the house wiring as it might not be properly grounded. Please check only if you are aware of the dangerous voltages present on electrical wiring (If you are a Professional in house wiring)I presume you are talking about iron or corrugated building. Rain releases static charge when in touches conductive surfaces and electrical system in a house should be well grounded to release this charges. Another problem could be active- neutral reverse polarity. check if any of your operating items are reversed polarized.ie active in place of neutral and neutral in place of active. This will affect in a item rated three phase operating on a single phase wiring. "Please contact a professional if you don't understand single and three phase electrical wiring" House wiring is dangerous as it deals with AC high voltages"Please take extra caution when dealing with High voltages"

      Likes(1)Dislikes(0)
      • Gopal Sharma

        August 8, 2014 at 6:14 pm

        Thanks Mr. Imraz. I appreciate your valuable suggestion. I will try the same.

        Likes(1)Dislikes(1)
    • Paulo Barbosa

      August 7, 2014 at 5:35 am

      You must have some leakage problem or intermittent short circuit, between the live terminal and the earth terminal. You must inspect visually the home electrical installion, that is the wall switches and wall sockets.

      Likes(1)Dislikes(0)
      • Jestine Yong

        August 7, 2014 at 12:33 pm

        Hi Paulo,

        Thanks for the suggestion. Since the replacement of the cap solved the problem (the aircond now is running well after more than a week) this means the capacitor internal part could have been shorted to ground through the casing.

        Jestine

        Likes(0)Dislikes(1)
    • Shanakr Nair

      August 8, 2014 at 12:18 pm

      it can add to your bill because the phase is being earthed at least partially through the wet wall and may be the conduit pipe which is being used.If the problem persists you must isolate the area where the earthing occurs and change the wiring.some times it so happens that there are unsealed joints in wires and the point gets wet by seeping water. when the ground is wet the shock is more damaging. so be careful.

      Likes(1)Dislikes(0)
  5. Yogesh Panchal

    August 6, 2014 at 1:56 pm

    Sir,
    Thanks for information , sir i have one question here how to discharge this type of capacitors other than using screwdriver because once i have used screwdriver for discharging the capacitor of water pump motor and with the spark my screwdriver was damaged too badly and literally broke into two-piece.

    Likes(0)Dislikes(0)
    • Jestine Yong

      August 6, 2014 at 3:01 pm

      Hi Yogesh,

      You can use a high wattage resistor like 1 K Ohm 10 to 20 watt to discharge it.

      Jestine

      Likes(1)Dislikes(0)
  6. skwong

    August 6, 2014 at 2:06 pm

    This is typical problem of air-cond .

    Likes(0)Dislikes(0)
    • Jestine Yong

      August 6, 2014 at 2:46 pm

      Hi Skwong,

      I believe yes because he could find the fault very fast. The important thing in this article is more on the safety issue. Discharging, removing and checking the cap can be easily done by a normal repair tech but climbing high wall fixing air-cond can be dangerous. Last year there was a local news about an air-cond repair tech slipped and fell-he died.

      Likes(1)Dislikes(0)
      • Donovan

        August 6, 2014 at 9:29 pm

        One danger is to get a non-lethal shock, that even though the shock itself would not kill you, it may knock you off the ladder which the fall will then kill you.

        Likes(1)Dislikes(0)
  7. Gerald

    August 6, 2014 at 2:26 pm

    Hi Jestine,

    This is a very interesting story. Thank you for sharing.

    Cheers,
    Gerald

    Likes(0)Dislikes(0)
    • Jestine Yong

      August 6, 2014 at 2:36 pm

      Hi Gerald,

      You are welcome.

      Jestine

      Likes(0)Dislikes(0)
  8. Waleed Rishmawi

    August 6, 2014 at 3:32 pm

    I have encountered such problem in my house about two years ago and it was due to the bad capacitor. in my case the earth leakage switch was not tripping but the air condition was not working..all I was hearing was the motor is humming because it was trying to turn but it could not. thanks for sharing the article.

    Likes(1)Dislikes(0)
    • Jestine Yong

      August 6, 2014 at 3:38 pm

      Hi Waleed,
      Thanks for sharing your success story.

      Jestine

      Likes(0)Dislikes(0)
    • Donovan

      August 6, 2014 at 9:32 pm

      The load was not sufficient to trip the breaker. Probably a lower wattage motor.

      Likes(0)Dislikes(0)
  9. Sirelkhatim

    August 6, 2014 at 4:02 pm

    Dear Young
    As usual good job I think the A/C has a run capacitor not starting cap because it remains in the circuit while the a/c is running thanks I always get value out of your repairs.

    Likes(1)Dislikes(0)
    • Jestine Yong

      August 6, 2014 at 8:19 pm

      Hi Sirel,

      Thanks. If you take a look at the amazon link it is refers to Compressor start capacitor:

      http://www.amazon.co.uk/CBB65-Conditioner-Compressor-Start-Capacitor/dp/B008AGMQ6C

      Jestine

      Likes(1)Dislikes(0)
  10. Robert

    August 6, 2014 at 4:06 pm

    Thanks for the article Mr. Yong. Good idea for calling a professional AC repair man. When we had problems with the main breaker outside tripping, I told them I would not mess with it. So we called a professional electrician. Turns out the whole main box from the pole outside was over 20 years old and needed replaced.

    Likes(0)Dislikes(2)
    • Jestine Yong

      August 6, 2014 at 8:14 pm

      Hi Robert,

      You have made the right decision in calling the professional electrician.

      Jestine

      Likes(0)Dislikes(0)
      • Robert

        August 6, 2014 at 9:30 pm

        Yes sir. I don't have the tools for those huge wires anyway. And I'm pretty sure it's against the law here in the US to work on mains AC if you're not a licensed electrician.

        Likes(0)Dislikes(1)
  11. Anwar Shiekh

    August 6, 2014 at 8:43 pm

    If I understand correctly it was the ground fault protection that was tripping and not the main breaker; did you check the resistance from the terminals to the case?

    Likes(1)Dislikes(0)
    • Jestine Yong

      August 7, 2014 at 12:02 pm

      Hi Anwar,

      It seems to be no reading. It could be shorting when under load. This is why it intermittently triggerring the ELCB.

      Jestine

      Likes(0)Dislikes(0)
  12. bernard

    August 6, 2014 at 10:19 pm

    dear Justine ,
    regaring the A/c drawing load, Here in India we install a separate mcb box with metal conduit plug at the A/c point, hence this should trip first instead of causing the MAIN BOX ELCB to trip, this way the other appliances (load) on the same Phase does not get affected and the fault is immediately isolated. FYI a fans starter capacitor when open exhibits a similar condition, thru experience we immediately change the capacitor... which I then open and show my Son and the class I teach ELECTRICAL MAINTENANCE & REPAIR ( SHOW AND TELL )
    Just sharing as an Electrical person.... I find all your articles very informative, and share them with my students .. regds bernie/~

    Likes(3)Dislikes(1)
  13. bernard

    August 6, 2014 at 10:23 pm

    Also when working and servicing A/c's extreme care must be taken as one can get overbalanced while handling heavy components, we had a case wherin an A/c Tech fell from 5 stories to the pavement below....

    pls ensure SAFETY , SAFETY FIRST

    regds bernard/~

    Likes(1)Dislikes(0)
    • Jestine Yong

      August 6, 2014 at 10:40 pm

      HI Bernard,

      Thanks for sharing the story.

      Jestine

      Likes(0)Dislikes(0)
  14. David Maltz

    August 7, 2014 at 12:28 am

    Great article! My friend who does air conditioning repair told me bad start up capacitors are one of the most frequent reasons he gets called to his customers homes. When the electric compressor motor can't turn due to a bad start up capacitor the motor draws excessive current until it begins to rotate. Even though the blower continually runs during operation the compressor motor needs to cycle on and off, so it
    makes sense that it would trip the circuit breaker as soon as the compressor tries to come on.
    As always I appreciate your repair articles. This sounds like something many of us are likely to see again.
    David Maltz

    Likes(1)Dislikes(1)
    • Jestine Yong

      August 7, 2014 at 11:58 am

      Hi David,
      Thanks for sharing.

      Jestine

      Likes(0)Dislikes(0)
  15. Paul

    August 7, 2014 at 12:54 am

    Hi Jestine,
    The ELCB is not a circuit breaker and does not trip due to "drawing too much current". It's more correct to call it an Earth Leakage Unit (ELU) which trips due to a fault current of between 25-30mA, so a very sensitive device. The other switches in your pic, are the Circuit Breakers (CB), and are rated for different current overloads, and marked accordingly, i.e. 10A; 20A; 30A etc.My guess is that your cap developed a fault to the can, causing a fault current flowing to ground (earth), causing the ELU to trip.
    Regards, Paul - Cape Town

    Likes(2)Dislikes(0)
    • Jestine Yong

      August 7, 2014 at 11:57 am

      HI Paul,

      You've got a point- thanks.

      Jestine

      Likes(0)Dislikes(1)
    • Tom

      February 4, 2016 at 9:10 pm

      Maybe Jestine has a dual-function breaker (ELCB and over-current breaker in one) and it was the over-current that tripped it. That would mean a bad breaker combo. A capacitor that turned open circuit would not leak electricity to ground (unless maybe it was doing so in bursts and unevenly?).

      Likes(0)Dislikes(0)
  16. Larry

    August 7, 2014 at 1:30 am

    Open starting cap is common with a cap starting motor. When one is stuck with a motor that hums but won't start that is needed "Now" like a water pump on a week end, You may get it started to pump up the water tank, for example, by shorting across the cap temperarilly, to get the pump started. It will run till the water pressure cuts it off. I have used this several times to keep us in water till I could get a new cap on Monday.
    Just use a plastic handled screw driver & be carful.

    Likes(0)Dislikes(0)
  17. Bill

    August 7, 2014 at 1:36 am

    I'm not familiar with the ELCB. Can you describe what it does and how it works?

    Likes(0)Dislikes(0)
    • Jestine Yong

      August 7, 2014 at 12:34 pm

      HI Bill,

      Try this link:

      http://en.wikipedia.org/wiki/Earth_leakage_circuit_breaker

      Jestine

      Likes(0)Dislikes(0)
  18. Imraz

    August 7, 2014 at 5:16 am

    Hi Mr Yong
    Nice article. Excellent technique to find the culprit

    Likes(0)Dislikes(0)
  19. Pete Singh

    August 7, 2014 at 5:42 am

    I just want a make sure (ELCB) same as(GFI) meaning ground fault intrepter . Regarding capacitor , yes the run capacitor hooked in series with the start winding of the compressor and for some reason if it open , the compressor will hum and will go on internal overload but defianately Would not trip the breaker . Please correct me if I am wrong. Thanks Pete Singh.

    Likes(1)Dislikes(0)
    • Jestine Yong

      August 7, 2014 at 12:30 pm

      Hi Pete,

      There is a possible leakage between the capacitor case and the ground when under load causing the ELCB to trip. The aircon man told me it was really rare to see an open cap could trip the ELCB.

      Jestine

      Likes(1)Dislikes(0)
  20. Paulo Barbosa

    August 7, 2014 at 5:45 am

    This problem is very frequent with the water pump electrical motors. When the start capacitor fails they do not work and do a typical very low humming sound.

    Likes(0)Dislikes(0)
  21. john

    August 7, 2014 at 4:31 pm

    V informative thks

    Likes(1)Dislikes(0)
  22. Joshua oloo

    August 7, 2014 at 4:34 pm

    Thanks Mr Yong for introducing us to caps. but this time on AC.Regards.

    Likes(1)Dislikes(0)
    • Jestine Yong

      August 7, 2014 at 4:45 pm

      You are welcome to all.

      Jestine

      Likes(1)Dislikes(0)
  23. Abdoulie Bah

    August 7, 2014 at 6:08 pm

    Well done good experience with AC and thanks for the info.

    Likes(1)Dislikes(0)
  24. nuhu adam

    August 7, 2014 at 6:46 pm

    nice repair tips especially the trouble shoot. keep it up.

    Likes(1)Dislikes(0)
  25. Gerald

    August 8, 2014 at 4:58 pm

    Very interesting discussion. Most ELCB have both functions:

    - Leak detection that will trip if the leak to the earth is equal or greater than 30 mA.

    - Circuit breaker that will trip if the current is more than a certain value, let say 20 A or 30 A (also depends on the timing). They are pretty complex devices.

    The device in the picture looks like one of those. So both scenarios would be possible. The leak to the earth is the most likely though.

    Cheers,
    GM

    Likes(1)Dislikes(0)
  26. Alphonsus Lim

    August 8, 2014 at 6:56 pm

    This is indeed a very good topic. Thank you very much Jestine Yong.

    I know of someone trying to save a little and lost his life. Pity the family he left behind.

    Thanks again Jestine

    Alphonsus

    Likes(1)Dislikes(0)
  27. Corriette

    August 9, 2014 at 1:57 am

    so true. capacitors should be tested after some time of appliance usage.but is there anyone who can advice when a capacitor should be tested for fault after usage? thanks

    Likes(0)Dislikes(0)
  28. Corriette

    August 9, 2014 at 2:01 am

    i have heard hums in washing machines and now wonder if it was capacitor problem? any idea any one?

    Likes(0)Dislikes(0)
  29. reza

    August 9, 2014 at 3:27 pm

    hello mr yong
    thank u

    Likes(1)Dislikes(0)
    • Nelson Caballero

      August 10, 2014 at 7:20 am

      Easy and handy to discharge a cap is your Soldering iron ac plug, electric fan ac plug, a 60w bulb with test leads, old screw drivers but keep an eye or be ready for the sparks. besides electronics ckts. are more more complex than your Air con. Sir. Caps on Aircon are very common so its a good practice to have 1pc spare. Any way your lucky its not the compressor. My AC fan motor capacitor was like that last year and it happens Friday Pm stores are closed next day Saturday closed Sunday closed, so its already Monday when I was able to buy it. And its funny all of my windows are open, with tons of electric fan on for 3 days.

      Likes(1)Dislikes(0)
  30. Sam Montero

    August 9, 2014 at 10:01 pm

    Hello Jestine

    I'm also ref. and aircon technicean. This I was not able to tell you other than Im on electronics. On the compressor of aircons there is a
    thermal cut off acting like a sloblo fuse. When there is a high current
    this would cut the circuit off. I wonder why this did not work on your
    unit. Maybe that your ELCB is more sensitive than the thermal cut off of your aircon.
    SAM

    Likes(1)Dislikes(0)
  31. biruk aweke

    August 14, 2014 at 2:26 pm

    HI MR Yong it is very nice idea thanks.

    Likes(0)Dislikes(0)
  32. Humberto

    August 19, 2014 at 7:08 pm

    Hi Mr. Jestine Yong, my old Air Conditioner had a similar trouble, the compressor motoe did not started, but the ELCB did not trip anyway. The capacitor was the culprit, when I substituted it with another one (russian made), it started and everything came to normality.

    Likes(1)Dislikes(0)
  33. Raymundo Saura

    August 27, 2014 at 4:22 pm

    nice great article hope i can read and re read all the articles so it will be stored on my mind once i met this one i knew how i will attack the problem thanks sir

    Likes(0)Dislikes(0)
  34. AJAZ JEE

    January 2, 2015 at 12:09 am

    GOOD

    Likes(0)Dislikes(0)
  35. Hachim

    January 19, 2017 at 12:43 pm

    We have been facing a very major problem of triping many elcb’s at a time.
    This happens when a fault occurs.
    started troubleshooting for this problem since a month ago, still not found any solution.
    What might be the problem for triping all the Elcbs's (at different floors DBs) at same time?

    Kindly request to help us to overcome this major problem.
    Thank you

    Hachim

    Likes(0)Dislikes(0)
    • Jestine Yong

      January 20, 2017 at 1:01 pm

      Hi Hachim,

      I have not came across such problem. I suggest that you ask a professional electrician to find out the fault because it is unusual to trip all ELCB at the same time.

      Jestine

      Likes(0)Dislikes(0)
      • Hachim

        January 21, 2017 at 1:41 pm

        ok jestine.
        Thanks for the response.

        Hachim,

        Likes(0)Dislikes(0)
  36. tclee

    April 30, 2017 at 1:55 pm

    Hi Yong,

    recently i have terrible ELCB tripping in my house , and i couldn't find out where's the problem.

    the tripping are strange,it starts around 9pm at night until 11am next morning(trips heavily around 11pm-6am,happens EVERY few minutes!!!).no problem at all during afternoon.

    at first i thought it was due to unstable incoming power supply,but this is not true because my neighbors got no tripping.

    then i decided to switch off individual MCB (2 or 3 MCB at one time)at the electrical panel,to try to troubleshoot which MCB is causing the problem.

    i tried out all the MCB (8 MCB at 1st floor,10 MCB at ground floor) but tripping still occurs.

    after that,i unplug every electrical devices (1 or 2 devices at one time)hoping to see which one is causing the problem,but tripping still occurs.

    at last,i switch off every lights (1 or 2 lights at one time) to check but problem still there.i give up.

    have you ever encounter this problem? pls advise,thanks.

    rgds,
    lee

    Likes(1)Dislikes(0)
    • Jestine Yong

      May 2, 2017 at 11:08 am

      Hi Lee,

      I have not encountered such situation before. I would do the same diagnosis like you if my house were having the same problem. The best is to get an electrician to check it. From your description, it would not be an easy task because it was having intermittent problem.

      Jestine

      Likes(0)Dislikes(0)
  37. RG

    August 10, 2017 at 10:09 pm

    Hi, MCB at my apartment trips when there is power outage. It actually trips when power is restored.It's building of 26 apartments. What could be the issue here?Is there problem in power supply from main unit to my apartment causing this?

    Likes(0)Dislikes(0)
    • Jestine Yong

      August 11, 2017 at 10:58 am

      Hi Rg,

      There are few causes why it can trip such as shorted electrical/electronic products, burn/shorted power lines in the concealed area, defective MCB and etc. You may need to find an electrician to do the fault finding.

      Jestine

      Likes(0)Dislikes(0)

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