New House - Strange Breaker Box Wiring

[kamalabob2]

Many thoughtful replies. I might add the OP should consider throwing away that 1800 baht "load center" and go buy a proper Schneider or Siemens or Panasonic load center. CT is not the quality and safety his family deserves. Yes and pull those undersized wires. There are licensed electricians in Thailand. The license number is listed on plans submitted to the PEA.  Now ethics and dishonesty to short size the wires is another issue. The cost difference is nominal between 1.5 and 2.5 electric wire in Thailand. 4.0 is not a budget buster, but I observe some Thai "electricians jacks of all trades' try to cut every possible corner.  Buying a reputable brand of load center with proper breakers including RCBO is a worthwhile expense. The load center need only catch fire one time and your savings have gone up in smoke. 

[bankruatsteve]

The RCBO test button is to test the RCD.  In doing so, it will trip the over current breaker.

[MrDetUdom]

33 minutes ago, kamalabob2 said:

Now ethics and dishonesty to short size the wires is another issue. The cost difference is nominal between 1.5 and 2.5 electric wire in Thailand. 4.0 is not a budget buster, but I observe some Thai "electricians jacks of all trades' try to cut every possible corner.

The crazy thing is, the builder just charged us a flat rate labor charge. We paid for all materials ourselves. So it would have cost the builder zero extra to go with larger wire.

 

Anyway, it turns out the RCBO is not even turned on. When I turn it on, it pops immediately. I guess this makes sense, since the neutral return is not actually going through the RCBO. The thing that really worried me though, is that even when I have all of the individual circuit breakers turned off, the RCBO still pops when activated. It seems entirely possible that the Live and Neutral coming in from the street are reversed (although that would also mean the live is connected directly to the earth spike, which seems unlikely). Unfortunately, went out to buy a multimeter today but could not find one, so no way to check. What a total <deleted>-up.

 

As for the tingle in the bathroom tap, it rained last night and the tingle went away today, so maybe the earth spike is not driven deeply enough.

 

Thanks everyone for recommendations for Udon Thani electricians. Unfortunately, we are in Ubon Ratchathani province. About 1.5 hour drive from the main city, and 20 minute drive from the nearest town (Det Udom). I confirmed today that when the PEA came to connect the power, they did not even look at the CU.

[Crossy]

4 hours ago, Antioc said:

The CXY RCBOs come completely wired and conform to Thai standards, they only require the Mains L and N to be connected. 

But of course they have to be connected correctly according to the instructions. Which our OPs sparks failed to do.

[Crossy]

5 minutes ago, MrDetUdom said:

I confirmed today that when the PEA came to connect the power, they did not even look at the CU.

Do you have a permanent supply? The easiest way to tell is the rate you're charged for power, should be about 4 Baht per unit, temporary power is about 8 Baht per unit.

 

Moving the incoming neutral across to the ground bar should make the RCBO work properly.

 

Your local hardware place should be able to supply a neon screwdriver, not ideal but at least you'll be able to verify polarity.

[maxpower]

2 hours ago, kamalabob2 said:

Many thoughtful replies. I might add the OP should consider throwing away that 1800 baht "load center" and go buy a proper Schneider or Siemens or Panasonic load center. CT is not the quality and safety his family deserves.

Suggesting the use of quality equipment is an excellent addition to this thread. We all know how the Thais like to save a few Baht for the next whisky session.

 

Not sure the OP could stand the pain from trashing his existing stuff though. 

[MrDetUdom]

2 hours ago, Crossy said:

Your local hardware place should be able to supply a neon screwdriver, not ideal but at least you'll be able to verify polarity.

I went out again and found a tiny little assorted junk shop that had a cheapo multimeter, so I got that. The polarity from the utility was correct, so I moved the neutral over to the earth bar and the earth spike as well. (Although I am no longer sure if the wires that I thought were the earth spike are actually the earth spike. They are both blue, and disappear up a conduit together with two brown wires which are just free with exposed tips inside the CU, packed in behind all the other wires.) Anyway, the upshot is that the RCBO now functions and although it still buzzes, it is barely perceptible. Even better, as soon as I turn on the bathroom water heater the RCBO trips, so it is clearly working. (Interestingly, there is also an RCBO in the bathroom right next to the heater that didn't trip, so I'm guessing the wiring is screwed up somewhere between the CU and the bathroom). As I was working on the CU the smell of burnt electrolyte (or burnt capacitor) was quite strong, so I'm guessing the RCBO may have suffered some damage from running with a large current through only one side. I'd like to change the CU, but that is definitely something I can't do by myself. I might go talk to the PEA directly and see if they have any recommends

 

It's also definitely a permanent supply. First bill just came in at just under 4 baht per unit.

[shaemus]

3 hours ago, MrDetUdom said:

The crazy thing is, the builder just charged us a flat rate labor charge. We paid for all materials ourselves. So it would have cost the builder zero extra to go with larger wire.

 

Anyway, it turns out the RCBO is not even turned on. When I turn it on, it pops immediately. I guess this makes sense, since the neutral return is not actually going through the RCBO. The thing that really worried me though, is that even when I have all of the individual circuit breakers turned off, the RCBO still pops when activated. It seems entirely possible that the Live and Neutral coming in from the street are reversed (although that would also mean the live is connected directly to the earth spike, which seems unlikely). Unfortunately, went out to buy a multimeter today but could not find one, so no way to check. What a total <deleted>-up.

 

As for the tingle in the bathroom tap, it rained last night and the tingle went away today, so maybe the earth spike is not driven deeply enough.

 

Thanks everyone for recommendations for Udon Thani electricians. Unfortunately, we are in Ubon Ratchathani province. About 1.5 hour drive from the main city, and 20 minute drive from the nearest town (Det Udom). I confirmed today that when the PEA came to connect the power, they did not even look at the CU.

Hi.

As normal you are being bombarded with advice. some good some bad in my opinion. (qualified, practicing and licensed electrician)

 

As some one mentioned above, throw out that switchboard. i just bought a similar unit to the Siemenns units metal clad with just a DP main switch/MCB and a set of MCB. I can now go ahead and remove the MCB as i choose to replace them with, RCBO's, surge protectors etc etc . For the money, well worth it. 

 

As for your Neutral set up. I am going to be frank here. If you follow the diagram provided by the PEA and the supply neutral is high resistance or Fails (common) you will be left with your earth bar/and whatever is connected to it as your Neutral and those of other properties  whilst your installation continues to work. I am aware that there may be a compliance issue with the PEA if you change your system but be honest look out your window and how many PEA installations or those connected to their network look safe to you. Danger being, if this situation occurs and you touch something earthed at a different potential whilst touch your metal cased equipment you will quickly start to feel. More tingles and may be smell burning. And even if you don't get a tingle you won't ever be able to disconnect from that situation even if you want to. i would steer clear of the MEN. you can google alot of research on it. It has two meanings, one UK One Aussie as far as i know. The Aussie one is to do with very dry ground and rocky terrain preventing households from getting a good earth thus the MEN (mechanically earthed Neutral)

 

Your cable issue, have a look at the Bangkok cable company website find the code for the cable type you want and google the code, you may well find it on lazada or even an enterprising wholesaler. I would suggest that you buy stranded cable rather than solid core. If you cant find 2c+e then buy 2c and run and earth cable with it. you can run the same size or a size down. I just bought a 25m roll of  2C+e 6mm² from homepro. I too am in Isaan, and i dont bother going to the smaller shops as the range can be limited, and i would rather go to a big shop and actually look at the whole range at my own leisure.  

 

You should definitely replace the cabling that is undersized, Use it as a pull wire to pull in your new cable

 

Earth Stake. if you cant see it then how do know it is there with out doing all sorts of tests. On your trip to the city . buy a big one and a big hammer. connect up using as large a cable as you see fit, you can use the black XLPE cable they have used for you supply as long as it is copper and not aluminium, I have a 25mm² cable to my earth rod

[Antioc]

15 hours ago, maxpower said:

Suggesting the use of quality equipment is an excellent addition to this thread. We all know how the Thais like to save a few Baht for the next whisky session.

 

Yep, just because it's made in Thailand it's up t# Sh##.  Not so, this stuff works fine and I have tested all the Breakers on these boxes.  Thais have been making this stuff for years and it works.  If you don't feel comfortable with local brands then certainly purchase another, you may find that the MCBs have been made in the same factory though.  I notice that many who comment are doing so on hearsay and not from actual experience.  This is not like tinkering with your car, you can end up very sorry if you don't know what you're doing.  Shaemus and Crossy, above have sound advice, the Thai Nuetral is Earthed at the Poles but still requires a decent connection to Earth from the Box.  Again HomeHub and other big stores have a full range of products including Earth Wires.

[maxpower]

2 hours ago, Antioc said:

Yep, just because it's made in Thailand it's up t# Sh##.  Not so, this stuff works fine and I have tested all the Breakers on these boxes.  Thais have been making this stuff for years and it works.  If you don't feel comfortable with local brands then certainly purchase another, you may find that the MCBs have been made in the same factory though.  I notice that many who comment are doing so on hearsay and not from actual experience.  This is not like tinkering with your car, you can end up very sorry if you don't know what you're doing.  Shaemus and Crossy, above have sound advice, the Thai Nuetral is Earthed at the Poles but still requires a decent connection to Earth from the Box.  Again HomeHub and other big stores have a full range of products including Earth Wires.

Funny guy, let me know where I can buy tickets for your next show.

[Antioc]

42 minutes ago, maxpower said:

Funny guy, let me know where I can buy tickets for your next show.

Yeah, I know, but.. I get a bit tired of the Thai bashers and the put downs.  As I said, not everything is second rate.  Many equivalent Western products cost more because of Taxes which make them appear to be a better product.  If you have plenty of money then buy a Mansion and a top-end motor vehicle but that's up to the individual.  Hope to keep the entertainment up, wouldn't want anyone going to sleep. 

Edited September 29, 2017 by Antioc
correction

[maxpower]

28 minutes ago, Antioc said:

Yeah, I know, but.. I get a bit tired of the Thai bashers and the put downs.  As I said, not everything is second rate.  Many equivalent Western products cost more because of Taxes which make them appear to be a better product.  If you have plenty of money then buy a Mansion and a top-end motor vehicle but that's up to the individual.  Hope to keep the entertainment up, wouldn't want anyone going to sleep. 

Work with jokers like PEA for several years and you too will become a basher.  Profit before safety is not easy to swallow.

 

Thailand is flooded with cheap Chinese electrical products some sub assembled and re-boxed here then stamped product of Thailand. If people are comfortable with copper coated toy alloys or gold coated steel terminals then they are free to pick up the bargain price brand X. Be aware, it might say 30mA trip on the box but when life depends on it after a few years in the humidity, who knows.

[Antioc]

50 minutes ago, maxpower said:

Work with jokers like PEA for several years and you too will become a basher.  Profit before safety is not easy to swallow.

 

I'm with you there.  I come from below the Equator where almost everything is made in China.  Not different now to the rest of the World which is why we are looking at big problems in the future.  I recently went looking for a set of stainless steel door hinges.  At first I was offered Chinese hinges, very cheep.  Then the chap came up with hinges made in Thailand which were indeed stainless, unlike all the Chinese ones which were merely coated.  The Thais make products more suited to their climate and are well aware of failures due to climatic conditions.  They too look down on cheap Chinese imports as my wife has demonstrated many times.  Products designed for Temperate climates may not be altogether suitable either.  We battle on, except the fact we will not always agree, and hope for the best.

[KKr]

On 9/27/2017 at 7:54 PM, MrDetUdom said:

This is the neutral that comes from the street pole/PEA.

 

In that case, I think it would make sense to remove the wire on top that connects the Neutral and Earth.
If you are not sure that your Earth is Earthed, just get a one or two meter copper spike from the local hardware and grocery and lao store and push / hammer that down in the earth in a place that is usually damp, that should give sufficient earthing when connected with a fat yellow and green wire to your switch box earth rail. 
The leakage breakers should work properly after that as well. As I understand, they get triggered by a difference between what is going into a circuit and what is going out. If not all is going out, that better go to a managed earth wire and trigger the safety, than through a person turning on the shower.
I'd also check those appliances that are not earthed for live leakage through an improperly connected neutral somewhere down the line in the wall or above the ceiling, or a mix up between live and neutral somewhere out of sight.
Then, moreover, test all earthed sockets to see that they have earth as well as neutral connected and live at the correct pin.
(but I am not a qualified engineer, so at your own risk, but I think you see the logic.)

Edited September 29, 2017 by KKr

[Crossy]

21 minutes ago, KKr said:

In that case, I think it would make sense to remove the wire on top that connects the Neutral and Earth.

Why would you remove a valuable safety connection?

 

Yes, TN-C-S with MEN is generally considered safer than TT despite the potential issues of an open neutral (which is why MEN is used not just TN-C-S).

 

Please, if you don't KNOW don't post.

 

And if you wish to LEARN (so you know in future) start here and scroll down https://en.wikipedia.org/wiki/Earthing_system

 

EDIT Please note, a TT system is permitted in Thailand unless it's a new installation. New installations must (I know, TiT) be MEN linked as shown.

[KKr]

32 minutes ago, Crossy said:

Why would you remove a valuable safety connection?

 

Yes, TN-C-S with MEN is generally considered safer than TT despite the potential issues of an open neutral (which is why MEN is used not just TN-C-S).

 

Please, if you don't KNOW don't post.

 

And if you wish to LEARN (so you know in future) start here and scroll down https://en.wikipedia.org/wiki/Earthing_system

 

IF it were better to connect Neutral to Earth, SURELY someone would have thought of that and done away with the third cable.

otherwise I agree with your post.

from your link: For these reasons, most countries have now mandated dedicated protective earth connections that are now almost universal.

Enuf said from my side.

 

Edited September 29, 2017 by KKr

[Crossy]

3 minutes ago, KKr said:

IF it were better to connect Neutral to Earth, SURELY someone would have thought of that and done away with the third cable.

 

NO!

 

That would be TN-C which is illegal (inside property) throughout the 220V world (and I understand the 115V world too) mainly due to the hazard of an open neutral between the point of use and the rod (you will die).

 

If you are from the UK you almost certainly have your N and E linked, but it's hidden in the service-head, what the eye can't see ...

[Crossy]

14 minutes ago, KKr said:

from your link: For these reasons, most countries have now mandated dedicated protective earth connections that are now almost universal.

Please do not cherry-pick quotes.

 

The whole paragraph states:-

 

Quote

For a time, US National Electrical Code allowed certain major appliances permanently connected to the supply to use the supply neutral wire as the equipment enclosure connection to ground. This was not permitted for plug-in equipment as the neutral and energized conductor could easily be accidentally exchanged, creating a severe hazard. If the neutral was interrupted, the equipment enclosure would no longer be connected to ground. Normal imbalances in a split phase distribution system could create objectionable neutral to ground voltages. Recent editions of the NEC no longer permit this practice. For these reasons, most countries have now mandated dedicated protective earth connections that are now almost universal.

My bold.

[shaemus]

3 hours ago, Crossy said:

 

NO!

 

That would be TN-C which is illegal (inside property) throughout the 220V world (and I understand the 115V world too) mainly due to the hazard of an open neutral between the point of use and the rod (you will die).

 

If you are from the UK you almost certainly have your N and E linked, but it's hidden in the service-head, what the eye can't see ...

Mr Crossy. 

 

Would be a good idea to pin a document with a definition of the supply types, TT, TNCS etc? So maybe these terminologies mean something to the less technically minded. Also i seem to recall the Ze being an important factor in the UK when it came down what supply the network would authorize. 

 

I can't imagine the PEA pay attention to the detail of impedance on a domestic front.

 

As for the OP. the CU he has currently may be made in Thailand, who knows? Who cares really. I am a strong advocate of the mantra Buy cheap buy twice. and i have to stop myself buying tat from time to time. Personally i dont want to have one protective device controlling the mainswitch. that is why i advocate the DIN railtype CU's as they are versatile. I find it hard enough to buy the simplest of things sometimes without having to go to extra expense by locking myself into Circuit breaker type (apart from DIN). As i mentioned before i just bought a Siemens 12 way CU as in the photo. Its to replace a Thai /China one which i bought about a year ago. where after being in the box the plastic has turned brown already. So rather than have to look at the bad decision i made which has cost me more now. i just replaced it with a full metal clad unit.

 

There was a comment made earlier about thai bashing. Now in my experience of this. Some things are more expensive here than from where i come from. Some things are better, some things are worse some things are cheaper. Things aren't built to high standards any more as a rule. if they were then the factories wouldn't have to work to replace or upgrade the items as they break down. The service / repair / replace market is out of control. Electronic goods are designed to have a life span by using the cheapest components. So given the choice, i try to buy the best to a certain extent. And this has been going on for years. Google the collusion between the light bulb companies in the early to mid 20 century. But there is an awful lot of crap goods for sale in Thailand.

 

And Crossy feel free to remove the attachment if its not within the rules, 

Uk earthing.pdf

[Crossy]

@shaemus We have thought about including general technical definitions, but we really want to keep stuff directly related to the situation in Thailand, if things start getting technical the Wiki page I link to (and your document, which apart from TN-S being very rare here, gives good explanations, thanks) does everything we really need.

 

Threads go off the rails when someone asks "why" (because that's the Thai regulations) and then questions the regulations because that's "not how we do it back home". Well guys, I have news for you, we're not "back home", if you want to pass the initial inspection you do it the Thai way (change it afterwards if you must, nobody will check).

 

The worst offenders are often "trained and licensed" electricians because they are trained in their authorities way of doing it to the exclusion of everywhere else.

 

There is also the difference between "prescriptive" regulations like the US NEC "do it like this and it's to code" with little or no actual testing, and "proscriptive" regulations like the UK BS7671 which describe what's required as an end result with very little "you must do this" leaving it to the electrician to design the system and then test to prove the end result is acceptable (this can result in a lower installed cost which can't be a bad thing).

 

I like to quote the "Pool Table Rules" from a favourite watering hole in Seoul, which state "We don't care what you do where you come from, this is what we do where you are".

 

[MrDetUdom]

I don't know if people here are interested in updates, but here are a couple of pics. The first one is the rewired box with the RCBO actually functional. The second one is a wiring diagram that is actually printed inside the cover of the CU. It's even in Thai, so not sure how the builder could have got it wrong. The last one shows the actual earth spike wire (the green one in the center). It's only a single 2.5mm2, so I guess I'll be running a new earth spike. (The earth spike is under the house, directly under the CU. One of the conduits in the wall goes down instead of up to access it).

 

The search for the earth spike uncovered another problem. The air conditioner is not earthed (I checked both indoor and outdoor units, and there is nothing). This may explain why some of the problems with the original wiring only started to occur after the air conditioner was turned on. The air conditioner installer is a different person from the builder, so the success rate of installers is going pretty low.

 

For the TNCS/TT argument, I'm happy to go with the Thai standard way. However, it does seem that TN-C-S with MEN relies on have a properly connected earth spike. We suffer momentary power failures here up to 10 times per day, with extended brown-outs and black-outs on a weekly basis. The locals blame it on trees falling on the lines, so as people have suggested, I really do have to do the earth properly.

 

For the CU, I do want to replace it. Whether the Thai one is just as good as a foreign one is beside the point. The current one simply doesn't have any free space inside. It is a mess. Having per-circuit RCBOs with inputs at the tops would solve a huge part of that, and after the issues with the bathroom water heater, I think RCBOs on every circuit is a must. Of course, when it comes to replacing the CU, I'm sure the proper way is to get the PEA to shutdown the power, then replace the CU, then have the PEA reconnect the power. I'm also sure that if I pay someone local to do it, they'll simply do it with the live still hot. Perhaps they'll wear some rubber-soled shoes as a safety measure.

 

Thanks everyone for your help

[Crossy]

8 minutes ago, MrDetUdom said:

For the TNCS/TT argument, I'm happy to go with the Thai standard way. However, it does seem that TN-C-S with MEN relies on have a properly connected earth spike.

Take a wander down your road, a properly implemented MEN will have the neutral (usually the top of the 4 LV wires) grounded every 3rd or 4th pole. If you don't see that grounded neutral, it may be sensible to go TT (but only if you know you're on a permanent supply, PEA won't accept TT for new supplies).

 

If you are going to replace the consumer unit anyway, I would add a 2-pole 100A switch to the incoming supply before the CU, MEN and all. You can then totally isolate your supply from the outside world for safe working on your system. I used a UK style main-switch that was in-stock but Chang do some lethal looking but actually perfectly fine knife switches. Keep it well out of reach, it's only needed occasionally.

[MrDetUdom]

3 minutes ago, Crossy said:

I would add a 2-pole 100A switch to the incoming supply before the CU, MEN and all

Yeah, that sounds ideal.

[Crossy]

10 minutes ago, MrDetUdom said:

Yeah, that sounds ideal.

This sort of thing http://www.ebay.co.uk/itm/MCG-100-AMP-MAIN-SWITCH-DISCONNECTOR-2P100AIS-/282620662543?epid=20003057432&hash=item41cd81130f:g:YesAAOSwWM9ZnE8R

 

 

Note, this is just a switch not an MCB. Nothing really to stop you using a 2-pole MCB but put it in its own small box so there are no live wires in your CU when you are working on it.

 

Or, if you think you may add a generator in the future one of these could be a wise investment.

 

http://www.ebay.co.uk/itm/125-amp-changeover-switch-240V-mains-to-generator-transfer-single-phase-Din-rail-/272258677525?epid=1661900551&hash=item3f63e1bb15:g:ouoAAOSwxKtX~6d5

 

[MrDetUdom]

On 9/30/2017 at 2:35 PM, Crossy said:

Take a wander down your road, a properly implemented MEN will have the neutral (usually the top of the 4 LV wires) grounded every 3rd or 4th pole. If you don't see that grounded neutral, it may be sensible to go TT (but only if you know you're on a permanent supply, PEA won't accept TT for new supplies)

OK, late reply, but I'm starting to think TT might be necessary. After replacing the 1.5mm2 wire with 6mm2 wire, the electric sensation got even worse. So I used my multi-meter to try and diagnose. Here's what we get:

 

Water heater has two elements, resistance roughly 11 ohm and 14 ohm, which translates to 3.5kW and 4.5kW. Total resistance is around 6.1 ohm with both on. Wire run from CU to heater is around 20m, which gives calculated 0.05 ohm resistance on each wire between CU and water heater, or 0.1 ohm round trip. When water heater off, supply voltage (line-neutral) at both CU and water heater is 220V. When one element on, around 200 V at CU and 197.5V, at water heater and with both on around 180V at CU and 175 V at water heater. The voltage drops between the CU and water heater are totally consistent with the calculated resistance of the 6mm2 wire. The neutral-earth voltage at the water heater is 2.5V when both elements on, and 1.25V when one element is on. This is consistent with the 5V drop across the live + neutral circuit from the CU to the water heater.

 

So the biggest issue is why the massive voltage drop at the CU when the heater is on. At full 8kW, there is a 40V drop. The wiring from the CU to the power pole is 16mm2 alloy, which has a resistance of 1.9 Ohm/Km. I would estimate wiring distance to street at 30m. Even if we use 50m to be conservative, that's only a 0.2 Ohm round trip resistance. That should only give a voltage drop of around 10V or less. So turning my hot water system on is causing a 30V drop at the utility wire. That seems kind of excessive.

 

But, getting back to the water heater. When it is on full, the voltage difference between the earth wire and water around the drain is 12V, which is pretty massive. I also guess that the true voltage is higher than this, since the drain piping is PVC, which is not exactly a great conductor. This suggests to me that there is no neutral connection to earth between our house and the transformer. I guess this means, when the hot water heater is on full, neutral+earth at our CU is around 20V, while live is around 200V. It also seems to mean that our current earth spike is completely non-functional.

 

I hadn't rushed to put in the new earth spike since the existing one is only a 2 m wire run straight down under the CU. Even though it is only 2.5mm2 cable, it seems like it should perform fairly well. (I'm just about to install a 16mm2 cable to an outside earth spike, but the cable run is rather circuitous, and is going to be around 20m, so the total resistance shouldn't be significantly different from the current earth spike).

 

So, I guess the question I have is whether I'm on the right track, and if anyone has any suggestions for other things I should check. One idea I had was to go solar to avoid any problems coming from the grid, but after all the dodgy stuff I've found that the builder has done, I don't have faith in putting extra loading on the roof.

Edited November 11, 2017 by MrDetUdom

[Crossy]

Hmmm, that 40V drop is pretty scary.

 

I would go TT at least for now, then you know the heater is at ground potential and you should not be getting tickles. Do that first.

 

Then we need to look at that volt drop. Can you check the voltage at the meter?

 

[MrDetUdom]

Thanks for all your help Crossy. I've finally discovered the last piece of the puzzle. None of the steel in the house has been bonded. I went up in the roof and bonded a couple of protruding rebar to the earth, and now there are no more tingles going on. (Still connected as TN-C-S). Voltmeter is showing 1 V between water heater and the drain (before it was showing 13V). I'll go around tomorrow and bond a bunch of other rebar and see how low I can get it down.

 

I don't have access to the meter, so could not check. However, I took a walk down the road and found the transformer. Google maps shows a distance of 550m, which explains the large drop. Not a single power pole had neutral earthed.

 

For the discussion between TN-C-S and TT, it occurred to me that a lot of western countries use copper water pipes that get bonded to earth at homes, and those copper pipes running through the neighborhood would effectively act as a TN-S system.

 

Anyway, the choice between TT and TN-C-S now seems to come down to how the meters here work. Does anyone know if they measure actual power or just do a conversion based on the current? If they measure current, I might try lay some copper earth cable down all the way to the back fence, which is much closer to the transformer.

[Crossy]

2 minutes ago, MrDetUdom said:

Anyway, the choice between TT and TN-C-S now seems to come down to how the meters here work. Does anyone know if they measure actual power or just do a conversion based on the current? If they measure current, I might try lay some copper earth cable down all the way to the back fence, which is much closer to the transformer.

 

If you don't see regularly grounded neutrals (and you have a permanent supply) I would go TT provided you have at least a front end RCD.

 

The meters in use here are true watt/hour meters, they use both voltage and current (and their phase-relationship) to measure real power.

 

[bankruatsteve]

On 11/13/2017 at 7:30 AM, MrDetUdom said:

None of the steel in the house has been bonded.

 

The structure steel should be "bonded" to earth internally (via the rebar in the concrete).  I haven't seen where additional bonding to earth stakes is required.

[RichCor]

Gotta wonder what's holding his roof on if it the steel wasn't welded to the concrete uprights.

 

I'm was a bit worried about the ~12-13v differential the poster was writing about in the shower. Was that measurement taken from the water Heater NEUTRAL and Heater GROUND to the wet floor? Ouch!  I'd really question what's going on with the NEUTRAL and EARTH GROUND link at his CU/Circuit Breaker. Something very wrong with the ground.

 

And tying the roof to ground is more about creating an alternate use Ufer Ground.  While I'm sure creating it is helping, having it help doesn't say much about the preexisting grounding system.