Adding an earth to a 15th floor 20 year old condo.

[CanadaSam]

I'd just break the wall to find any section of rebar iron support rod, and use it as an earth.

 

(But I'm not electrician).

[najomtiensun]

Have got a reply to my question from someone in the condo....

 

The metal water pipe would be a decent option but all our metal supply pipes are corroded and need replacing. This project is on the agenda for the AGM (when we can have it) and, if accepted, will involve the replacement with plastic pipes of all the metal water pipes on the supply sides of the meters. So when that is done your new earth lead would no longer be connected to anything.

Our neutral leads are bonded to earth in the utility rooms. I am an IT consultant not a qualified electrician, but as I understand it this is common practice.

It might be worth looking into fitting an RCBO of the type that does not require an earth connection to function. As I understand it this will provide more protection than adding a separate earth lead would anyway, as it should trip fast if there is any type of overload or short. That may not satisfy your water heater installers though as they are probably just working to instructions that require them not to fit the device if there is no earth. Another installer would probably not be so fussy.

https://uk.rs-online.com/web/generalDis ... rcbo-guide

Powerbuy fitted my new water heater without any issues. There is an earth lead in my bathroom supply that they used but in fact that lead goes no further than the breaker box. They did not check that the lead actually went anywhere. They just wanted to see it and to connect to it.

Some people bond their earth leads to the steel in the building structure, but that is not always accessible and probably isn't a very good idea anyway.

 

[bankruatsteve]

2 minutes ago, najomtiensun said:

I am an IT consultant not a qualified electrician,

Anything else?

[lopburi3]

32 minutes ago, najomtiensun said:

It might be worth looking into fitting an RCBO of the type that does not require an earth connection to function. As I understand it this will provide more protection than adding a separate earth lead would anyway, as it should trip fast if there is any type of overload or short.

True and they do not require a ground wire to operate - but they only operate when electric finds alternate path to ground - through you if no other path (case not grounded).  Not a nice feeling at best and it could potentially kill if your stars are not in good alignment (although that chance in small - and heaters themselves have built in ELCB and shower hose is normally isolated by plastic connector).  But expect a high percentage of such heaters do not have a real ground and the death rate is a whole lot less than the gas heaters that were normal previously.   But building rebar should be available somewhere to make a real ground.  An iron rail on balcony if not able to use elevator shaft?

[bankruatsteve]

3 minutes ago, lopburi3 said:

But building rebar should be available somewhere to make a real ground.  An iron rail on balcony if not able to use elevator shaft?

Balcony railing may not be attached to structural steel making it as good a ground as drilling a hole in the wall.  The OP apparently has exposed structural steel above the ceiling which should be excellent source.

[DefaultName]

I used building maintenance to try to get an electric oven earthed.  After about 40 minutes he told me it needed an earth, Buddha knows what he thought he was doing up to that point.  Then he spent 30 minutes trying to earth to rebar in the concrete kitchen worktop.   I gave up, the oven is in and working, but not earthed.

[bankruatsteve]

2 minutes ago, DefaultName said:

trying to earth to rebar in the concrete kitchen worktop

Again, rebar in a countertop is not likely to be connected to structure making it ineffective as earth.

[najomtiensun]

4 minutes ago, DefaultName said:

I used building maintenance to try to get an electric oven earthed.  After about 40 minutes he told me it needed an earth, Buddha knows what he thought he was doing up to that point.  Then he spent 30 minutes trying to earth to rebar in the concrete kitchen worktop.   I gave up, the oven is in and working, but not earthed.

I reluctantly accept no earth up to the point of a shower in a  bathroom. That's a red line for me. 

[OneMoreFarang]

Rebar was mentioned a couple of times here. Is that really a reliable option for earth?

When I was young I helped on constructions sites in my school holidays. And I don't think the steel in the concreate was connected to each other. Obviously often the pieces of steel "touched" each other. But as far as I know there is no intended electrical connection. So whatever is connected might have a bad electrical connection. Add 15 floors of bad electrical connections and I wouldn't call that earth anymore.

What do you think? I am happy to be corrected and learn.

 

[natway09]

I am pretty sure there will be an earth to the main distributor board at the service room mains.Talk to the "sparke" who looks after the condo or is employed by same first 

[OneMoreFarang]

3 minutes ago, najomtiensun said:

I reluctantly accept no earth up to the point of a shower in a  bathroom. That's a red line for me. 

How about using a plastic pipe between the heater and the shower? That would at least remove any metal electrical connection.

[DefaultName]

8 minutes ago, bankruatsteve said:

Again, rebar in a countertop is not likely to be connected to structure making it ineffective as earth.

I know, my point was that the "electrician" didn't.

[OneMoreFarang]

1 minute ago, natway09 said:

I am pretty sure there will be an earth to the main distributor board at the service room mains.Talk to the "sparke" who looks after the condo or is employed by same first 

How many of those electricians are qualified?

It seems many of them work according to the motto: I connect two wires, it works (i.e. the light goes on), and that's it.

And I am pretty sure if someone would ask them about the difference between neutral and earth many wouldn't know any difference. Or to say it in Thai: same same.

[bankruatsteve]

9 minutes ago, OneMoreFarang said:

Rebar was mentioned a couple of times here. Is that really a reliable option for earth?

When I was young I helped on constructions sites in my school holidays. And I don't think the steel in the concreate was connected to each other. Obviously often the pieces of steel "touched" each other. But as far as I know there is no intended electrical connection. So whatever is connected might have a bad electrical connection. Add 15 floors of bad electrical connections and I wouldn't call that earth anymore.

What do you think? I am happy to be corrected and learn.

Rebar is used to reinforce concrete.  It is usually connected to structural steel in columns but usually not otherwise.  Structural steel is well connected and good source for earth.  See "Ufer ground".

[jomtienisgood]

On 1/15/2021 at 1:08 PM, Dumbastheycome said:

OOPs! Earth bar  quite  naked !

Very strange indeed. It used to be naked girls in the bars...555555

[xylophone]

19 minutes ago, natway09 said:

I am pretty sure there will be an earth to the main distributor board at the service room mains.Talk to the "sparke" who looks after the condo or is employed by same first 

That's a possible option, however I wouldn't advocate using rebar because of all the points mentioned, and one  doesn't know where that particular piece rebar starts and stops!

 

The condo people have already said they have problems with the water pipes rusting away, so that's not an option, so my suggestion about dropping an earth down the service duct and then connecting it to an earth, even if it's through driving a stake in the ground, is still a possibility.

 

If you can get a sparky to open up the main distribution board for you, you can see if there is an earth in it and then find a way to connect to it, even if it means using the service duct. If there isn't an earth, then you'll have to use the stake in the ground suggestion. 

 

PS. For what it's worth I was qualified electrical technician before I left that profession and went on to others, and I have an abject fear of the little electric water heaters used here, because a number of them which I have been asked to inspect, didn't have an earth, but luckily enough I've been able to run one for these people.

[sometimewoodworker]

1 hour ago, najomtiensun said:

Some people bond their earth leads to the steel in the building structure, but that is not always accessible and probably isn't a very good idea anyway.

Why why don’t you think  it is a good idea? FWIW BS 7671 amendment 2 is going to require it so there is a group who disagree.

[najomtiensun]

10 minutes ago, xylophone said:

That's a possible option, however I wouldn't advocate using rebar because of all the points mentioned, and one  doesn't know where that particular piece rebar starts and stops!

 

The condo people have already said they have problems with the water pipes rusting away, so that's not an option, so my suggestion about dropping an earth down the service duct and then connecting it to an earth, even if it's through driving a stake in the ground, is still a possibility.

 

If you can get a sparky to open up the main distribution board for you, you can see if there is an earth in it and then find a way to connect to it, even if it means using the service duct. If there isn't an earth, then you'll have to use the stake in the ground suggestion. 

 

PS. For what it's worth I was qualified electrical technician before I left that profession and went on to others, and I have an abject fear of the little electric water heaters used here, because a number of them which I have been asked to inspect, didn't have an earth, but luckily enough I've been able to run one for these people.

I share that fear hence the post - could be cold showers from now on if there isn't an affordable solution to the problem. Which actually isn't that bad... 

[bankruatsteve]

You can lead a horse to water....

[Pilotman]

Move

[sometimewoodworker]

41 minutes ago, xylophone said:

I wouldn't advocate using rebar because of all the points mentioned, and one  doesn't know where that particular piece rebar starts and stops!

You do not have any need to know the start and stop point of a particular section of rebar is and in general it’s totally irrelevant. Ufer grounded systems are never reliant on a single rebar length, rebar is always tied together and the concrete itself, though not a great conductor compared to metal, is often/usually better than a ground rod due to the large areas involved and in soil contact.
 

You need to test the rebar (not so easy in a condo sure) to discover if it’s a good ground or not. In general the test will confirm that it’s good, but a test is still needed.

[paulbrow]

1 hour ago, OneMoreFarang said:

How about using a plastic pipe between the heater and the shower? That would at least remove any metal electrical connection.

For what it's worth, the water itself is a fine conductor, pretty much nullifying the plastic pipe, hence the need for a solid ground.

[lopburi3]

1 minute ago, paulbrow said:

the water itself is a fine conductor

Actually water is a fine insulator - it is the impurities in the water that conduct.  ????

[bankruatsteve]

3 minutes ago, paulbrow said:

For what it's worth, the water itself is a fine conductor, pretty much nullifying the plastic pipe, hence the need for a solid ground.

Actually, pure water is an insulator.  Water can conduct, albeit not as a good conductor, if it has metal ions in it: salt, lime scale, heavy metals.

[paulbrow]

Just now, lopburi3 said:

Actually water is a fine insulator - it is the impurities in the water that conduct.  ????

Pure water is as you say, but we are talking about city water which is anything but pure.

[xylophone]

29 minutes ago, sometimewoodworker said:

You do not have any need to know the start and stop point of a particular section of rebar is and in general it’s totally irrelevant. Ufer grounded systems are never reliant on a single rebar length, rebar is always tied together and the concrete itself, though not a great conductor compared to metal, is often/usually better than a ground rod due to the large areas involved and in soil contact.
 

You need to test the rebar (not so easy in a condo sure) to discover if it’s a good ground or not. In general the test will confirm that it’s good, but a test is still needed.

My point about the Rebar was that you don't really know if it's connected to anything else, especially knowing the building conditions here in Thailand.

 

In addition the Ufer grounding system was reliant upon a direct connection to earth through the building, and not through Rebar which is tied together, and again it's never sure here whether anything will match that requirement!

 

True enough a sparky could test whether the earth is good or not.

 

And as for using the steel building structure for an earth, well even though it is mentioned in the new IEE regulations, I suspect that the rationale for doing this is not to provide an earth to which people can bond their electrical setups, but as a safety backup to ensure that any stray voltage in the building, goes to earth.

 

And a point on the IEE regs – – they are not always that "straightforward" and I say this because I remember in the 11th or 12th edition, there was a paragraph stating that an electrical fitting should not be installed under a direct water outlet, BUT, if this was unavoidable then the fitting should be............I'm sure you get my drift. 

[sometimewoodworker]

49 minutes ago, xylophone said:

My point about the Rebar was that you don't really know if it's connected to anything else, especially knowing the building conditions here in Thailand.

Having built here and having looked in on numerous building sites you are wrong the buildings here, as far as rebar and concrete work is concerned  is reasonable. Also that the concrete IS part of the earthing. Also a test is required in the OPs case to confirm.

 

In my house a test would only confirm that the rebar is grounded, in the OPs case slightly less sure.

 

49 minutes ago, xylophone said:

In addition the Ufer grounding system was reliant upon a direct connection to earth through the building, and not through Rebar which is tied together, a

That misunderstanding demonstrates your total lack of comprehension of the Ufer grounding system. This is common with many British sparkies who will not take the time to understand a different system.

 

49 minutes ago, xylophone said:

And as for using the steel building structure for an earth, well even though it is mentioned in the new IEE regulations, I suspect that the rationale for doing this is not to provide an earth to which people can bond their electrical setups, but as a safety backup to ensure that any stray voltage in the building, goes to earth.

I doubt that your suspicion has any grounding in fact.

[OneMoreFarang]

1 hour ago, sometimewoodworker said:

You need to test the rebar (not so easy in a condo sure) to discover if it’s a good ground or not. In general the test will confirm that it’s good, but a test is still needed.

How to do such test?

I work with electronics and I have a multimeter and other tools. But I have no idea how to check for good earth (on rebar).

[bankruatsteve]

2 minutes ago, OneMoreFarang said:

How to do such test?

I work with electronics and I have a multimeter and other tools. But I have no idea how to check for good earth (on rebar).

You are more likely to find exposed structural steel than rebar.  Whatever.  A simple test you can connect a wire to the steel and run it to your CU (breaker box).  Check voltage between L and wire connected to the steel.  If it is pretty much the same as voltage between L and N, you have a good ground.

[sometimewoodworker]

1 minute ago, OneMoreFarang said:

How to do such test?

I work with electronics and I have a multimeter and other tools. But I have no idea how to check for good earth (on rebar).

Regrettably you almost certainly don’t have the correct test equipment. This is a case where a correct test needs a professional Electriction with the correct (expensive) test equipment and training to use it. Most places here will skip the tests and just hope.