Thailand fuseboard RCCB issue

Поделиться
HTML-код
  • Опубликовано: 29 окт 2024

Комментарии • 11

  • @retrozmachine1189
    @retrozmachine1189 6 месяцев назад

    Was just about to comment that the N/E link is downstream of the RCD which is likely why the RCD was tripping. A percentage of neutral current (relative to the neutral and earth path impedance) will be able to return via the earthing if it is in contact with the ground - bonds, electrode, incidental earthing of plumbing via water heater etc. Once the load on the system rises sufficiently to get => 16mA of difference on the incoming wires, off she goes. Good diagnosis. Good that you corrected the orientation of the RCD too. Electrical in SE Asia is .. creative.

    • @Steveuploads
      @Steveuploads  6 месяцев назад +1

      Thanks. Yes the Neutral to earth bond is a rule in Thailand, I’ve recently found out. It works but when a meter is replaced and if the L+N is swapped over accidentally all the appliances and all other earthed metal become live straight from the meter before the house protective devices, which is how I found this installation with the metal fuse box live.
      I fitted the new RCBO upside down as you aaw so it could work correctly and then left fully expecting it would trip but I just wanted to see it happen before I rectified it finally. The ground rod earth I have connected also to the fuseboard Earth terminal is just two foot of galvanised threaded rod hammered into the earth outside. This is a rubbish earth but I did it just to gain a reference to Earth to determine which of the two blue incomers were the live. When I splashed the Earth cable from the rod on to incoming Live from the meter i was surprised that when I brushed the Earth cable strand which I’d stripped back to simulate a fuse wire against incoming live from the meter it just sparked instead of blowing the copper strand to bits, it just sparked lightly. In hindsight it may have been that i was brushing against the terminal screw or similar material that can prevent good contact. I have checked for electricity on many occasions previously when chasing a fault in control wiring and realised screws have a coating that insulates it so you must always touch the cable going into the terminal not the terminal screw.
      I wanted to see if the Earth was good. I ‘ guess ‘The neutral to earth fault was not a high enough current because the Earth impedance with the poor Earth rod set up I hashed up was not effective to trip the RCBO after reset within a good time frame, or even better would have been ‘ immediately’ as if would normally as touching N+E together when we cut a twin cable cable with the live nrwaker off and the main RCBO trips when it senses the imbalance with the E-N fault, as you know.
      Also as the incoming Neutral is bonded to my new Earth Rod it occurs to me that if someone removes the load side meter tales for isolation of the house as people do but mistakingly reverse them the live will now be joined to the Earth Rod and will blow up in the hapless electricians face as he pushes the cable back into the live load side meter terminal. The only way to prevent this situation is to sink the rod at the meter and join it at that point so the guy messing with the meter can see that the neutral is earthed and hopefully not make that mistake which would go bang. It’s now that I’m thinking that maybe the PEA who are the Thai Electrical Authority maybe don’t want the customer having an Earth Rod for just this reason but how can the customer prevent the supply being swapped accidentally at or before the Meter which would render all the metal extraneous parts of the electrical appliance becoming live. The only protection the customer has is to earth the incoming Neutral as an insurance policy.

    • @retrozmachine1189
      @retrozmachine1189 6 месяцев назад

      @@Steveuploads I was going to mention checking service polarity with an independent earth but since the RCD was actually capable of holding in at all indicated polarity was correct since it would only need 32mA to ensure the trip and even a crappy earth rod should be capable of that if you put phase onto it.

    • @Steveuploads
      @Steveuploads  6 месяцев назад +1

      I’ve edited my main thoughts, the comment that starts “ Thanks “ if you’d like to reread it. It was garbled as i was in a hurry to leave the house 😀

    • @retrozmachine1189
      @retrozmachine1189 6 месяцев назад +1

      @@Steveuploads Normally if you have reverse polarity and your earthing (including bonds and incidentals) is truly independent of other installations, so no metal pipework to the neighbours that provides a path via their earthing system back to neutral etc, all that will happen is you put some amount of current into the earth depending on the electrode impedance.
      10 ohm earth rod which is quite low for what you've described, about 23A. I think you are from the UK or surrounds, so think of the typical impedance of a TT earth electrode if it helps. Sparks, yes, bang, usually no and if there is a service fuse it typically won't blow. It's possible to calculate the loop impedance of just the rod with a multimeter (clamp type is easiest) and say a kettle if you don't have a meter than can do a proper loop test. Bit dangerous though.

    • @Steveuploads
      @Steveuploads  6 месяцев назад +1

      @retrozmachine1189
      So normally when I touch a live to earth it goes bang because if the full loop impedance Zs on a tester is maybe 0.8 Ohms. 220v / 0.8ohms = 275A flowing to earth. Are you expecting 10 Ohms earth and 20 odd amps ? I can assume if Earth is combined with N it will be a big bang. It’s been along time since my Sparky days. My earth is rubbish, it’s a piece of Galv threaded Rod. Am I not gonna get 200 V plus flowing in an Earth fault to blow a breaker quick if I sink a proper Earth Rod ? Currently the only appliance earthed is the fuse box. The spark who wired the job didn’t loop an Earth single around the power outlets as they do here.

  • @AnonNot
    @AnonNot 6 месяцев назад

    You have colors wired incorrectly Blue is neutral Brown/Black/Grey is live

    • @Steveuploads
      @Steveuploads  6 месяцев назад +2

      This is how the Local Thailand Electrician has wired it. How is it me that has the colours incorrect? It’s a video about a fault
      It’s Thailand. I’ve seen many times two blues at switches am I supposed to rewire the whole house ? I’ve solved why the RCD was tripping. Don’t come on telling me about electric I’ve forgotten more than you know. Do one.