liddelljohn Posted December 12, 2023 Share Posted December 12, 2023 When i use the oven the MCB trips out whole house , Had this problem before turned out to be Door bell getting moisture in , we replaced it and sealed that unit 3 years ago but now same problem again , The breakers are correct Amperage the 30amp circuit RCD for OVEN is separate and nothing else trips the system RCDs ever ,, only The Oven and that causes MCB to trip but not the RCD disconnecting doorbell and all outside electric does help , but its not a viable solution and the Thai electricians are all out of their depth. any solutions , because I use my oven a lot , but I need outside lighting and doorbell The oven is in perfect order its not very old , and works perfectly when disconnected from Earth , but thats not a safe option I just did it to make sure the oven was fine .. Link to comment Share on other sites More sharing options...
bluejets Posted December 12, 2023 Share Posted December 12, 2023 (edited) 1 hour ago, liddelljohn said: The Oven and that causes MCB to trip but not the RCD 1 hour ago, liddelljohn said: and works perfectly when disconnected from Earth These two comments contradict each other. Are the above part of the one breaker or two independant units...?? Photos thanks. Other than that I'd say you are sufferning from effect of voltage drop and your disconnecting the earth is simply nothing to do with the situation. Get PEA to check any and all connections at the pole/meter........(twist and tape territory in Thailand..........aluminium mains capital as well) Use gas where mains cover long distances and you insist on using undersize mains as per Vdrop calculations. Edited December 12, 2023 by bluejets Link to comment Share on other sites More sharing options...
OneMoreFarang Posted December 13, 2023 Share Posted December 13, 2023 Did you try a new MCB? Link to comment Share on other sites More sharing options...
digbeth Posted December 13, 2023 Share Posted December 13, 2023 are you sure the mains wiring to the oven is big enough, 4sq mm at least for oven Link to comment Share on other sites More sharing options...
liddelljohn Posted December 13, 2023 Author Share Posted December 13, 2023 5 hours ago, OneMoreFarang said: Did you try a new MCB? yes we have done that , but no difference ,, Link to comment Share on other sites More sharing options...
liddelljohn Posted December 13, 2023 Author Share Posted December 13, 2023 4 hours ago, digbeth said: are you sure the mains wiring to the oven is big enough, 4sq mm at least for oven yes wires are 4sq mm,, all the houses here in out village are built with ovens and have 30amp 4sq mm circuit for it Link to comment Share on other sites More sharing options...
degrub Posted December 13, 2023 Share Posted December 13, 2023 A/C cycling on when mcb trips and oven on ? same for water heater ? or other motor driven device ? water well pump ? just some ideas. Link to comment Share on other sites More sharing options...
OneMoreFarang Posted December 13, 2023 Share Posted December 13, 2023 MCBs trip if more current flows through them then their max current rating (i.e. 16A). RCCBs and RCBOs trip because of leakage (mostly max 30mA = 0.03A). Maybe something is wrong with the wires or the outlet (if there is one). One common problem is that people connectors with low power ratings to connect wires together. Many of them are rated maybe for 10A or 16A, which is not enough for many hobs (which are maybe part of your oven). 1 Link to comment Share on other sites More sharing options...
bluejets Posted December 13, 2023 Share Posted December 13, 2023 (edited) 16 hours ago, OneMoreFarang said: MCBs trip if more current flows through them then their max current rating (i.e. 16A). RCCBs and RCBOs trip because of leakage (mostly max 30mA = 0.03A). No...combo's will trip from either and usually there is a trip indicator showing whether over current or earth leakage. The earth leakage may be 30mA but the trip current would depend on many conditions including current rating and class of breaker. Still waiting for photos of sw board setup from OP to make further educated comment. Edited December 13, 2023 by bluejets 1 Link to comment Share on other sites More sharing options...
OneMoreFarang Posted December 13, 2023 Share Posted December 13, 2023 26 minutes ago, bluejets said: No...combo's will trip from either and usually there is a trip indicator showing whether over current or earth leakage. The earth leakage may be 30mA but the trip current would depend on many conditions including current rating and class of breaker. Still waiting for photos of sw board setup from OP to make further educated comment. Thanks for your correction. You are of course correct. I tried to make it simple, but my explanation was a little too simple. 1 Link to comment Share on other sites More sharing options...
liddelljohn Posted December 14, 2023 Author Share Posted December 14, 2023 we have checked all visible wires , no damage at all the cable choccy bloc connector is not plastic but an industrial ceramic one rated 100a , No other equipment a/c, pumps cycle , and when all other circuits in house disabled the oven still makes MCB trip,, the only thing that affects this is the doorbell circuit that seems live all the time unless bell is disconnected ,, without the oven I cant cook the food I like .. all my neighbours have same system thats 209 houses and no one has reported any issues with oven and I have asked dozens . PEA have checked and said nothing wrong ?????? Link to comment Share on other sites More sharing options...
degrub Posted December 14, 2023 Share Posted December 14, 2023 (edited) Reading your original post again, oven works when not safety earthed, no trip and trips when earth is connected ( to frame i assume), it would appear there is a fault or leakage to frame ? Do all of the other surveyed working ovens have a safety earth connected ? Do i understand correctly that there is no issue if the safety earth is disconnected from the oven ? Either that or the circuit is overloaded as indicated by the statement that removing the doorbell and outside lights “helps” ? Edited December 14, 2023 by degrub Link to comment Share on other sites More sharing options...
Liquorice Posted December 14, 2023 Share Posted December 14, 2023 Sounds like an earth leakage fault with your oven appliance. Link to comment Share on other sites More sharing options...
liddelljohn Posted December 14, 2023 Author Share Posted December 14, 2023 5 hours ago, Liquorice said: Sounds like an earth leakage fault with your oven appliance. Yes definitely earth leak fault ,, but all tests indicate the OVEN itself is OK the old oven which had same fault is now in a friends house and is ok ,, the fault is baffling everyone I have had round ,,no on can isolate it ??? 5 hours ago, degrub said: Reading your original post again, oven works when not safety earthed, no trip and trips when earth is connected ( to frame i assume), it would appear there is a fault or leakage to frame ? Do all of the other surveyed working ovens have a safety earth connected ? Do i understand correctly that there is no issue if the safety earth is disconnected from the oven ? Either that or the circuit is overloaded as indicated by the statement that removing the doorbell and outside lights “helps” ? Without the earh the oven is unsafe as its live all over , when earthed its not live to touch but it trips out the system, Its a new oven the old one was doing the same , but is now in a friends house and is working fine ....?? all tests on Oven wiring circuits are inconclusive , I had PEA, some electricians etc Link to comment Share on other sites More sharing options...
liddelljohn Posted December 14, 2023 Author Share Posted December 14, 2023 (edited) Real issue is i cant get anyone here who is able to find , solve or isololate where the problem is exactly I cant cook now without an oven whole thing is farcical # just need a competent electrician with correct tools and diagnostics Edited December 14, 2023 by liddelljohn Link to comment Share on other sites More sharing options...
degrub Posted December 14, 2023 Share Posted December 14, 2023 (edited) Is this an issue that was not there, then appeared suddenly after a change in the house electrical - something was added or changed ? Or was this present from the beginning- initial construction ? is this issue present no matter if it has rained or not ? you say it gets better when the doorbell and outside lights are turned off or is it when they are physically disconnected from power ? How and where are those physically connected to the oven wiring ? i would think that the oven would/should have dedicated wiring from the breaker box to the oven with the only cross connect at the N buss bar and Safety Earth buss in the breaker box. Does the oven require 3 wires (L,L2, N) or 4 (L, L2, N, S) by design ? either way, it sounds to me ( not an electrician and US based, Thailand is not the same electrical implementation), like the Neutral or possibly safety earth has been crossed with a Neutral return somewhere or a Load supply. Has anyone measured the voltage differences between L-S, N-S, L-N, L2-S, L2-N at the wall connection with the oven physically disconnected ? if the outdoor lights and doorbell were somehow spliced into what should be a dedicated circuit for the oven…… could be a nail or screw, cut in wire insulation within conduit, device fault, a miswiring, etc. just some ideas. Edited December 14, 2023 by degrub US basis, not Thailand, UK, or Aus. Link to comment Share on other sites More sharing options...
Liquorice Posted December 14, 2023 Share Posted December 14, 2023 2 hours ago, liddelljohn said: Real issue is i cant get anyone here who is able to find , solve or isololate where the problem is exactly I cant cook now without an oven whole thing is farcical # just need a competent electrician with correct tools and diagnostics Send a PM to @Crossy He's a competent electrician working in Thailand. Link to comment Share on other sites More sharing options...
Liquorice Posted December 14, 2023 Share Posted December 14, 2023 1 hour ago, degrub said: i would think that the oven would/should have dedicated wiring from the breaker box to the oven with the only cross connect at the N buss bar and Safety Earth buss in the breaker box. It's quite common in Thailand to find appliances of higher amperage to be connected directly to the incoming tails from the meter unit. The meters are on poles erected externally to the house. Link to comment Share on other sites More sharing options...
liddelljohn Posted December 14, 2023 Author Share Posted December 14, 2023 the system in my house has dedicated wiring and breaker just for oven with4sqmm cable all conected to MCB and then to meter with all other wiring its a standard setup for here same as previous house ,, but this problem is so odd it makes no sense . 32 minutes ago, Liquorice said: Send a PM to @Crossy He's a competent electrician working in Thailand. yes but he is in Bangkok im in Sattahip??? but i will ask him . Link to comment Share on other sites More sharing options...
Crossy Posted December 14, 2023 Share Posted December 14, 2023 OK let's try and sort this one out once and for all. First thing we need @liddelljohn is some photos: - The device which is tripping, after it has tripped - So we know exactly what we are looking at. Your CU / distribution board with the lid off (care please). The rating plate of your oven. Have you tried an appliance of similar rating (kettle, toaster) in place of the oven? Can you try the oven on a different circuit? Have you re-checked that the doorbell/outside lighting hasn't got the damp in again? I'm suspecting some sort of earth leakage but let's gather some evidence. Note:- The oven being live-case when the ground is off isn't necessarily a fault, elements do tend to leak somewhat, and of course, any switching power supplies will have mains filters. Also, do you have any test gear (multimeter)? Link to comment Share on other sites More sharing options...
liddelljohn Posted December 15, 2023 Author Share Posted December 15, 2023 I have a multimeter,,will take some photos and upload the oven was taken to my friend house and it works fine there ,,no tripping Link to comment Share on other sites More sharing options...
liddelljohn Posted December 16, 2023 Author Share Posted December 16, 2023 how do I load photos here from phone Link to comment Share on other sites More sharing options...
Crossy Posted December 16, 2023 Share Posted December 16, 2023 33 minutes ago, liddelljohn said: how do I load photos here from phone Start a new reply to the thread. Click on "Add Files" at the bottom of the window. Click "My files" Click "images" That should open your Gallery where you can select images to add Click "Done" EDIT Forget to add, you need to "insert" each photo into your post where you want them before submitting the post, if you don't I think it just lumps them all together at the end. Link to comment Share on other sites More sharing options...
liddelljohn Posted December 17, 2023 Author Share Posted December 17, 2023 Photos uploaded. Oven mcb outdoor Bell etc Link to comment Share on other sites More sharing options...
terryq Posted December 17, 2023 Share Posted December 17, 2023 May be nothing but there is a view that the problem is earth leakage related. From your photo of the distribution board notice that the trip is set to only 5mA. This may be too sensitive. Try setting to the standard 30 mA and check if any improvement . 2 Link to comment Share on other sites More sharing options...
Crossy Posted December 17, 2023 Share Posted December 17, 2023 As @terryq suggests, first try your RCBO at 30mA, it's no less safe than 5mA is really. Are you really feeding mains through that doorbell push? Those things are surely not IP65 or better which they ought to be when outdoors in the wet. I'd really look to modifying that to a low-voltage doorbell system. Can you show a close-up photo of the RCBO section after a trip so we can see the indicator flags please. 1 Link to comment Share on other sites More sharing options...
liddelljohn Posted December 24, 2023 Author Share Posted December 24, 2023 Thanks guys ,, upping the MCB trip and removing and changing doorbell circuit seems to have sorted the oven it stays on for more than a hour ,, girlfriend says her son turned the MCB down ??? 1 Link to comment Share on other sites More sharing options...
Crossy Posted December 24, 2023 Share Posted December 24, 2023 RCD problems seem to be en-vogue at present, at least that's one off the list 1 Link to comment Share on other sites More sharing options...
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