Forkinhades Posted January 1, 2010 Share Posted January 1, 2010 Does the rubber mat really make a difference? WIth all the water flowing over it, will that still allow the electricity to flow? I am not being argumentative; I really want to know. will not make any difference at all Link to comment Share on other sites More sharing options...
Forkinhades Posted January 1, 2010 Share Posted January 1, 2010 (edited) As a side issue, electricity is like drugs, you can build up tolerance to its effects. I have been involved with electricity for over 60 years and normal mains shocks are nothing worse than an irritation, many people use a neon screwdriver to test if a wire is live, I often just brush my finger over the wire. Note, this is not a recommended method for most people. Why would you want to offer useless information like this, and how the heck do you know that the cable is live?, if you was 'grounded' yourself you would get a shock, otherwise you do not have a potential difference in voltages, and thus would not feel anything. Edited January 1, 2010 by LivinginKata Flame removed - LivinginKata Link to comment Share on other sites More sharing options...
jbhh Posted January 1, 2010 Share Posted January 1, 2010 People, IF you read this (which I hope) and you live in Thailand, you should invest in a residual-current circuit-breaker. I find it amazing that not all households have this, with this in place you could drop the hairdryer in the bathtub while sitting in it and at most feel a little sting before the power is cut off. http://en.wikipedia.org/wiki/Residual-current_device R.I.P poor kid... Link to comment Share on other sites More sharing options...
GungaDin Posted January 1, 2010 Share Posted January 1, 2010 ^^^^ Good link, thanks jbhh, now I have a better idea what all those TLAs are about. RIP the German lad...... another avoidable tragedy in the land of "mai pen rai" (don't give a sh*t) Link to comment Share on other sites More sharing options...
sauvagecheri Posted January 1, 2010 Share Posted January 1, 2010 And to add my "two cents " why not use solar units to heat water ,therfore avoiding the use of electricity all together ,its cheap and very efficient in a sun drenched country ... Link to comment Share on other sites More sharing options...
markokang Posted January 1, 2010 Share Posted January 1, 2010 Don't forget earth and RCBO when you install a water warmer ! Thats the whole point, there are no earths in Most Thai homes and certainly not in apartments, the units they sell cover themselves by saying it must be earthed but there is nothing to earth it too unless you install an earth stake and cable into your home, in an apartment there is no option for that! Link to comment Share on other sites More sharing options...
Forkinhades Posted January 1, 2010 Share Posted January 1, 2010 And to add my "two cents " why not use solar units to heat water ,therfore avoiding the use of electricity all together ,its cheap and very efficient in a sun drenched country ... WLF, it does not matter where the supply comes from,, it is still dangerous. Link to comment Share on other sites More sharing options...
HannahD Posted January 2, 2010 Share Posted January 2, 2010 Perhaps we should all be back in the West where sanity prevails? War against Iraq; war against Afghanistan; war against Pakistan; war against Yemen; and war against Iran on the not too distant horizon. That's sanity? At least in LOS we have some control over the hazards we must deal with. The electrocutions are a genuine tragedy and Condolences to the families. Yet Thailand is not engaged in wars against anyone and blowback is not a hazard here. Link to comment Share on other sites More sharing options...
atyclb Posted January 2, 2010 Share Posted January 2, 2010 http://www.helpinaflash.com/House-Projects...ker-Install.cfm http://www.easy2diy.com/cm/easy/diy_ht_ind...age_id=35720244 Link to comment Share on other sites More sharing options...
fiercesnake Posted January 2, 2010 Share Posted January 2, 2010 As an Electrician, it does amaze me why Thai buildings (including ones farang have built for them)are always missing the Earth, as well as being wired up completely wrong. The very sad thing is, that there are laws that the Thai's are meant to abide by and sign a certificate saying the electrical installation is safe. Obviously no one checks or actually cares. I would also say, I was checking out the wiring in the new Shell Petrol Station in Phuket, and being Shell, i would have thought their would be standards... Alas I was wrong. Very poorly wired with 3 phase 25mm cables coming in, earthed by a 4mm cable... = death when a problem occurs. But at least there was an Earth.... did it work... dunno... maybe it just looked good. TB Dead right! "Dead" being the operative word ! I've said this time and time again; safety in Thailand MUST be taken more seriously! It is not part of the culture here to consider potential risks or consequences. There is still too much reliance on old traditional religious notions that Buddha will protect! I can understand when people are not well educated that this is a reasonable belief but it is a flawed ideology. I like to suggest that people use more common-sense and a little less belief in supernatural forces protecting you from stupidity. I've heard an old saying for those believing in religion; "God looks after those who look after themselves." The proverb suggests that you will be protected but only if you don't put yourself in harm's way through your own stupid behaviour. Getting people (including farangs) here to consider potential risk is vital if things are to improve. This is one area in which we should NOT be complacent just to avoid upsetting local culture. If we see a sus wire or something that looks dangerous, then if we can say something about it to someone then perhaps we should. Maybe this death could have been avoided if the electrician installing it would have taken more care or ensured a good Earth connection or made sure that it was connected to a high quality circuit breaker; or the question must be asked did a REAL electrician actually install it or was it just some local bozo to save money? More I think, more likely it was management saving money and getting Uncle Tom to screw in a few bolts and hook it up rather than getting someone in that knew what to do. Earthing problems here are massive, as are poor electrical safety standards across the board. Even as a Science teacher in an upmarket and newly built school, I was stunned to find no separate electrical shut off control with a good quality circuit breaker for my Physics students doing electrical experiments. I had to whinge and moan to get one when it should have been standard and that was in a GOOD school, how much more in some other dodgy establishments??? Hence it is a matter of education and not just in electrical safety. Safety across all areas in this country needs improvement through massively improved education programs in their local media and especially technical colleges and universities. Link to comment Share on other sites More sharing options...
dhrobertson Posted January 2, 2010 Share Posted January 2, 2010 RCBOs are known as ELCBs in Thailand. They replace standard MCBs in the load panel / consumer unit. NO GROUND is required in either case. Link to comment Share on other sites More sharing options...
dhrobertson Posted January 2, 2010 Share Posted January 2, 2010 How can one determine if the electrical system in a condo is "earthed" If it isn't can metal water plumbing be used as "earth" as it would not be easy to run a wire to the ground floor. The question is not just is it earthed? The question is "is the earth good enough?". We need to ensure that, in the case of a ground fault, sufficient current flows to ground that the breaker trips. Ask a professional! Link to comment Share on other sites More sharing options...
dhrobertson Posted January 2, 2010 Share Posted January 2, 2010 How can one determine if the electrical system in a condo is "earthed" If it isn't can metal water plumbing be used as "earth" as it would not be easy to run a wire to the ground floor. Yes, but only if the metal water plumbing is earthed Maybe, but not necessarily. We need to know if the ground fault loop impedance is low enough. Ask a professional. Link to comment Share on other sites More sharing options...
dhrobertson Posted January 2, 2010 Share Posted January 2, 2010 Look, this is serious stuff. A 32A breaker requires 320A to trip quickly. That means we need a ground loop impedance of less than 0.7ohms. You will never achieve this with a ground rod. Fit an ELCB (RCBO) or use a TN-C-S ground system. Again ask a professional! Link to comment Share on other sites More sharing options...
dhrobertson Posted January 2, 2010 Share Posted January 2, 2010 maybe the adiabatic equation equalled 4mm Ha! Exactly, brother sparks! Link to comment Share on other sites More sharing options...
dhrobertson Posted January 2, 2010 Share Posted January 2, 2010 Thats the whole point, there are no earths in Most Thai homes and certainly not in apartments, the units they sell cover themselves by saying it must be earthed but there is nothing to earth it too unless you install an earth stake and cable into your home, in an apartment there is no option for that! All instant hot water shower heaters now have an integral ELCB/RCBO. They are perfectly safe even with no ground. HOWEVER we always recommend having a good ground bond AND ELCB/RCBO protection. Link to comment Share on other sites More sharing options...
ColinChapman Posted January 2, 2010 Share Posted January 2, 2010 There seems to be a lot of misunderstanding about ELCBs and RCCBs, perhaps it is a difference of terminology between American and British usage. Thank you for the crystal clear explanation of the differences between RCCB and ELCB. I live in a condo and all the sockets have an earth wire. My water heater has an ELCB, which I test regularly with the test button. Having read this thread at length, I am not sure whether this means I am protected if the earth wire is not connected to earth but is actually connected to neutral? Is there a way that I can test whether my earth is actually earthed or whether it is just connected to the neutral? I do have a multimeter. Link to comment Share on other sites More sharing options...
dhrobertson Posted January 2, 2010 Share Posted January 2, 2010 Actually, the Thai EIT code is pretty good. It is more stringent than BS7671 in that RCBOs are required for all water heaters. Real problem is lack of inspection. Link to comment Share on other sites More sharing options...
dhrobertson Posted January 2, 2010 Share Posted January 2, 2010 Thank you for the crystal clear explanation of the differences between RCCB and ELCB.I live in a condo and all the sockets have an earth wire. My water heater has an ELCB, which I test regularly with the test button. Having read this thread at length, I am not sure whether this means I am protected if the earth wire is not connected to earth but is actually connected to neutral? Is there a way that I can test whether my earth is actually earthed or whether it is just connected to the neutral? I do have a multimeter. As previously stated, a ground connection is not required for proper operation of ELCB or RCBO. Glad that you test your unit regularly as RCBOs can stick. By the way, Neutral is bonded to ground at the transformer and usually at several places along the route to your appliance. In TN-C-S ground systems, neutral is again bonded to ground at the origin of your system. Link to comment Share on other sites More sharing options...
dhrobertson Posted January 2, 2010 Share Posted January 2, 2010 Here's a good one for your students. Let's say we have a perfect 6kW water heater. Let's assume a good ground rod which meets the requirements of the PEA/MEA with an impedance of 5 ohms to the main body of the earth. If the supply is 220V RMS (lets assume zero internal impedance) but the live (phase) wire has a resistance of 1 ohm and the ground wire has a resistance of 1 ohm. If there is a solid ground fault at the water heater, what current will flow to ground and what will be the voltage at the water heater? If the breaker is rated at 32A with a C characteristic (10x rated current for magnetic trip), how long will it take the breaker to trip? Answer: install an RCBO! Link to comment Share on other sites More sharing options...
ramisi Posted January 3, 2010 Share Posted January 3, 2010 RIP he had his whole life in front of him. I heard the tragic news from a very close friend of the mother(and auntie of the boy). What is so tragic and heart wrenching is that the boy had only just been speaking to his mother on the phone(she was away working on a yacht a few thousand miles away) just barely an hour before the tragedy happened. Please everyone check your showers, when I returned home I checked mine and it was faulty. It is now renewed(the copper heater casing soldered joint was weeping quite badly and it was not earthed!!!). The heater was new 10 years ago when we moved into the rental and I had assumed it was OK. We dont nead lessons like this to wake people up. When buying my new heater I noticed that all new heaters had a sticker on the front(in Thai) warning about properly earthing these appliances. Link to comment Share on other sites More sharing options...
Forkinhades Posted January 3, 2010 Share Posted January 3, 2010 maybe the adiabatic equation equalled 4mm Ha! Exactly, brother sparks! ahem engineer to you brother Link to comment Share on other sites More sharing options...
Forkinhades Posted January 3, 2010 Share Posted January 3, 2010 Here's a good one for your students. Let's say we have a perfect 6kW water heater. Let's assume a good ground rod which meets the requirements of the PEA/MEA with an impedance of 5 ohms to the main body of the earth. If the supply is 220V RMS (lets assume zero internal impedance) but the live (phase) wire has a resistance of 1 ohm and the ground wire has a resistance of 1 ohm. If there is a solid ground fault at the water heater, what current will flow to ground and what will be the voltage at the water heater? If the breaker is rated at 32A with a C characteristic (10x rated current for magnetic trip), how long will it take the breaker to trip? Answer: install an RCBO! good question, but in the UK under test this would fail, as you are only allowed an impedance of 0.75 ohms for 32 A type C circuit, and you state the impedance is 2 ohms, so the MCB would not trip in time, (=death) but an RCCB WILL trip at around 40 milliseconds, even if the earth rod had an impedance of 10 ohms This is why we test all the wiring in the UK before we turn the supply on ! Also if you wanted to get the impedance down to levels below 0.75, you should be using a 6mm cable (live) and 2.5mm (earth) for the shower circuit, even with a RCCB installed your trip times could exceed 400 milliseconds (=death) with an undersized cable. Now go check the size of cable for your heater, I bet it is only 2.5mm (live) and No Earth!, or if it has an earth 1.5mm Link to comment Share on other sites More sharing options...
Forkinhades Posted January 3, 2010 Share Posted January 3, 2010 (edited) Thank you for the crystal clear explanation of the differences between RCCB and ELCB.I live in a condo and all the sockets have an earth wire. My water heater has an ELCB, which I test regularly with the test button. Having read this thread at length, I am not sure whether this means I am protected if the earth wire is not connected to earth but is actually connected to neutral? Is there a way that I can test whether my earth is actually earthed or whether it is just connected to the neutral? I do have a multimeter. As previously stated, a ground connection is not required for proper operation of ELCB or RCBO. Glad that you test your unit regularly as RCBOs can stick. By the way, Neutral is bonded to ground at the transformer and usually at several places along the route to your appliance. In TN-C-S ground systems, neutral is again bonded to ground at the origin of your system. @ dhrobertson granted it will still work without an earth, but it is still dangerous as the trip times might exceed 400 milliseconds (=severe injury/death), with an earth installed you will get trip times less than 40 milliseconds @ ColinChapman ok so you are testing your ELCB, but you will not know how quick it operates, unless you have the proper test equipment. Edited January 3, 2010 by Forkinhades Link to comment Share on other sites More sharing options...
ColinChapman Posted January 3, 2010 Share Posted January 3, 2010 @ ColinChapman ok so you are testing your ELCB, but you will not know how quick it operates, unless you have the proper test equipment. Thanks, that is what I wanted to know, does the fact that the test button works mean I am safe, and your answer is "no"! So, I still need to check if the earth wires in my condo are actually connected to earth. Is there a way I can do this with a multimeter or does it require more specialist equipment? Link to comment Share on other sites More sharing options...
Forkinhades Posted January 3, 2010 Share Posted January 3, 2010 Thanks, that is what I wanted to know, does the fact that the test button works mean I am safe, and your answer is "no"!So, I still need to check if the earth wires in my condo are actually connected to earth. Is there a way I can do this with a multimeter or does it require more specialist equipment? To test the quality of the earth you do really need specialist equipment, to test if you have an earth, you can use a voltmeter, and in this order, set the meter to measure in the 230V range, put one of the leads on the earth terminal FIRST, then the other lead on the live terminal, if you get a voltage of 230V it suggests you have an earth, but will not tell you how good the earth is, more importantly you should be testing the time RCD trips under fault conditions. A recent job of mine in the UK, I tested a commercial property, which Did not have an earth coming into the site, but there was an earth connected at the Fuseboard, which was then connected to the water pipe, and had an RCCB, under test the RCCB DID NOT trip!! I got the electrician to install a earth rod, got a reading of 3.4 ohms, under test the second time, the RCCB tripped in 38 milliseconds @ 1 x fault current, and tripped in 12 miliseconds @ 5 x fault current. Hope this makes things very clear You need a good earth AND a good RCCB which trips within the times Link to comment Share on other sites More sharing options...
paulfr Posted January 3, 2010 Share Posted January 3, 2010 (edited) Here's a good one for your students. Let's say we have a perfect 6kW water heater. Let's assume a good ground rod which meets the requirements of the PEA/MEA with an impedance of 5 ohms to the main body of the earth. If the supply is 220V RMS (lets assume zero internal impedance) but the live (phase) wire has a resistance of 1 ohm and the ground wire has a resistance of 1 ohm. If there is a solid ground fault at the water heater, what current will flow to ground and what will be the voltage at the water heater? If the breaker is rated at 32A with a C characteristic (10x rated current for magnetic trip), how long will it take the breaker to trip? Answer: install an RCBO! DhRobertson I have a question for you. In a shower or bathtub ..... Can one eliminate the possibility of danger by using fixtures [handles and knobs on the shower/bath controls] that are plastic [insulators] rather than metalic [conductors] ? You do need to touch something other than the water to get zapped, no ? Thanks Edited January 3, 2010 by paulfr Link to comment Share on other sites More sharing options...
Forkinhades Posted January 3, 2010 Share Posted January 3, 2010 DhRobertsonI have a question for you. In a shower or bathtub ..... Can one eliminate the possibility of danger by using fixtures [handles and knobs on the shower/bath controls] that are plastic [insulators] rather than metalic [conductors] ? You do need to touch something other than the water to get zapped, no ? Thanks No, the water can still become live, would you put an electric fire in a bathtub and sit in it? Link to comment Share on other sites More sharing options...
dhrobertson Posted January 3, 2010 Share Posted January 3, 2010 maybe the adiabatic equation equalled 4mm Ha! Exactly, brother sparks! ahem engineer to you brother I stand corrected! Good to have someone on board who knows his stuff! Link to comment Share on other sites More sharing options...
dhrobertson Posted January 3, 2010 Share Posted January 3, 2010 Here's a good one for your students. Let's say we have a perfect 6kW water heater. Let's assume a good ground rod which meets the requirements of the PEA/MEA with an impedance of 5 ohms to the main body of the earth. If the supply is 220V RMS (lets assume zero internal impedance) but the live (phase) wire has a resistance of 1 ohm and the ground wire has a resistance of 1 ohm. If there is a solid ground fault at the water heater, what current will flow to ground and what will be the voltage at the water heater? If the breaker is rated at 32A with a C characteristic (10x rated current for magnetic trip), how long will it take the breaker to trip? Answer: install an RCBO! good question, but in the UK under test this would fail, as you are only allowed an impedance of 0.75 ohms for 32 A type C circuit, and you state the impedance is 2 ohms, so the MCB would not trip in time, (=death) but an RCCB WILL trip at around 40 milliseconds, even if the earth rod had an impedance of 10 ohms This is why we test all the wiring in the UK before we turn the supply on ! Also if you wanted to get the impedance down to levels below 0.75, you should be using a 6mm cable (live) and 2.5mm (earth) for the shower circuit, even with a RCCB installed your trip times could exceed 400 milliseconds (=death) with an undersized cable. Now go check the size of cable for your heater, I bet it is only 2.5mm (live) and No Earth!, or if it has an earth 1.5mm Exactly the point!! Link to comment Share on other sites More sharing options...
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