How safe are wall mount water heaters without earthing ?

[retell]

As long as the steel framing is actually truly grounded (via the copper rod deep into the soil), AND the various parts of the framing are actually tightly joined in this case welded, then that should be fine.

Don't rely on the mass of steel itself to be "a ground" because it isn't enough mass, will have a differential from that of the earth itself whereas all your grounded outlets need to actually be all joined together to the same ground.

However it would be better to just have three-wire cabling throughout the house, and all the ground wires from every outlet all come together in the same place at the wiring box and from there to the common ground, a single properly sunk copper rod.

i know , but after a few tests all works fine , i used 6 3 meter copper rods with the wires soldered and taped on them a quick check with the multi from the furthest point to the rod must far away gave me next to 0 resistance ( the bit it had was the same as the long wires i used to test ) ground loops have no problem with those cos my stereo equipment , turn tables , amps are all humm free

[boosta]

Retell I know you knew what you were doing, just rephrasing for clarity wrt Transam's comment.

[taninthai]

it would be pretty difficult to get a shock from the one in the op as it is all plastic the danger comes when it is a conductive material

[retell]

it would be pretty difficult to get a shock from the one in the op as it is all plastic the danger comes when it is a conductive material

indeed the tubes and hoses are plastic / pvc but the heating element is copper in direct contact with water that is 30 centimeter away from your head

[transam]

it would be pretty difficult to get a shock from the one in the op as it is all plastic the danger comes when it is a conductive material

Not if water is leaking inside and hits terminals.

[Naroge]

it would be pretty difficult to get a shock from the one in the op as it is all plastic the danger comes when it is a conductive material

The plastic cover will not protect you if there is an internal fault. The current will go through the water.

[MrBrad]

I know that earthing ours with rods into the ground wasn't exactly financially challenging. Perhaps Bt1000 each ?

I thought under a 100 bht each.

I've not priced the copper rods, but I've heard (and certainly believe) that some of the "copper" rods are steel or another metal coated in copper color. I think that a genuine copper rod would cost more than 100 baht. You need the real thing for proper grounding.

[transam]

I know that earthing ours with rods into the ground wasn't exactly financially challenging. Perhaps Bt1000 each ?

I thought under a 100 bht each.

I've not priced the copper rods, but I've heard (and certainly believe) that some of the "copper" rods are steel or another metal coated in copper color. I think that a genuine copper rod would cost more than 100 baht. You need the real thing for proper grounding.

As far as I am aware the rods are steel strands with a REAL copper outer sheath. I have bought a few and they are all the same.

[Naroge]

I know that earthing ours with rods into the ground wasn't exactly financially challenging. Perhaps Bt1000 each ?

I thought under a 100 bht each.

I've not priced the copper rods, but I've heard (and certainly believe) that some of the "copper" rods are steel or another metal coated in copper color. I think that a genuine copper rod would cost more than 100 baht. You need the real thing for proper grounding.

Yes, 100 Baht will not even cover the material cost for real copper.

[taninthai]

it would be pretty difficult to get a shock from the one in the op as it is all plastic the danger comes when it is a conductive material

The plastic cover will not protect you if there is an internal fault. The current will go through the water.

it would be pretty difficult to get a shock from the one in the op as it is all plastic the danger comes when it is a conductive material

The plastic cover will not protect you if there is an internal fault. The current will go through the water.

water doesnt actually conduct electricity that well its the same with glass ,if your wet it just lowers your bodys resistance,ive looked into it and its pretty unlikely the electricity would travel through the water well not enough to kill you anyway.

Edited June 22, 2013 by taninthai

[boosta]

OK, you go ahead and put your theory to the test, we'll watch.

"Ah I love the smell of napalm in the morning!"

[paulfr]

Water, if distilled or deionized, is an insulator.

It does NOT conduct electricity.

BUT

Impure water does conduct very well.

All tap water has salts and other impurities

and thus is a good conductor.

JFYI

[boosta]

Perfect solution then, rather than fixing your electric system, just put a water distillation factory on your roof and use that for showering - sound good to me. . .

[Crossy]

water doesnt actually conduct electricity that well its the same with glass ,if your wet it just lowers your bodys resistance,ive looked into it and its pretty unlikely the electricity would travel through the water well not enough to kill you anyway.

As others have noted, tap water isn't pure by any stretch of the imagination, mix that with the salts on your skin and it becomes a pretty good conductor.

Also don't forget the metallised shower hose, that will conduct pretty well too (and you have one end in your hand).

People and tourists die every year from electrocution in the shower, water and wet bodies figure in most of these instances.

[retell]

I know that earthing ours with rods into the ground wasn't exactly financially challenging. Perhaps Bt1000 each ?

I thought under a 100 bht each.

I've not priced the copper rods, but I've heard (and certainly believe) that some of the "copper" rods are steel or another metal coated in copper color. I think that a genuine copper rod would cost more than 100 baht. You need the real thing for proper grounding.

a good way would be to drive a stripped copper wire with a steel pipe several meters into the ground

[Crossy]

I've not priced the copper rods, but I've heard (and certainly believe) that some of the "copper" rods are steel or another metal coated in copper color. I think that a genuine copper rod would cost more than 100 baht. You need the real thing for proper grounding.

a good way would be to drive a stripped copper wire with a steel pipe several meters into the ground

Solid copper is not necessary for your ground rod, in fact you can use almost anything metallic except Aluminium.

Suitable materials include:

• Solid copper (expensive)
• Copper clad steel (less expensive but check the thickness of the copper)*
• Galvanised steel (cheap, and hot-dip galvanising lasts a long time)*
• Stainless steel (expensive again)

* The issue with both copper clad and galvanised steel is the cut ends where the steel itself is exposed and corrosion can start.

The weak point is always the connection between your earth wire and the rod, differing metal contact can corrode rapidly. Make sure the connection is totally dry (Wifey's hair dryer can be of use here) then paint it with a good acrylic paint to keep it that way. It will last for years. Do not bury the connection, you'll need to check it occasionally.

[sandrabbit]

They have the potential to electrocute you if they are not earthed

and an internal fault occurs.

Not only that but they also need to be protected with an ELB

(earth leakage breaker) that is fitted in the supply line through the

Live and Neutral.

Only earthing is NOT 100% safe.

And without an earth the ELB is useless.

again <deleted>, there is no earth connection on an rcd and the reason you get an electric shock is because you have made a current path to ground. the rcd detects that the neutral current is lower than the live current so some current is flowing to ground so therefore it does not require an earth. people get killed because of bad advice.

Is it complete <deleted>?

He said ELB/ ELCB.

You are talking about an RCD/RCCB which of course doesn't require an Earth as it measures Residual Current and doesn't care how the loss got to Earth?

Whether you approve of them or not, will an Earth Leakage Circuit Breaker function without an Earth?

.

rcd, elcb, elb are the same thing

Edited June 23, 2013 by sandrabbit

[sandrabbit]

They have the potential to electrocute you if they are not earthed

and an internal fault occurs.

Not only that but they also need to be protected with an ELB

(earth leakage breaker) that is fitted in the supply line through the

Live and Neutral.

Only earthing is NOT 100% safe.

Absolute <deleted>, if there is correct earthing and the heater element becomes live then the current will flow to ground through the earth which should then trip the circuit breaker.

Without RCB or ELB protection the circuit breaker that your referring to will only trip when the amperage exceeds the maximum the circuit breaker is rated at which is usually 32A or higher.

With an RCB or ELB incorporated the amperage is up to 30 milliamps before it trips, which makes

it a life saver.

There is nothing <deleted> about what i said.

of course it is the fault current which trips the circuit breaker (whatever the circuit breaker rating is ) but no current flows through the person (possibly pico or micro amps) because the impedance to ground through the earth wire is very low and that's why there should be a large cross section earth cable.

[ABCer]

I may be wrong, but a metal rod is not adequate. A sheet of copper minimum 2 ft x 2 ft with a copper wire bolted on with two copper washers buried in about 1 m deep ground will give a better conductivity. If in the place close to moisture -better still.

BTW wire does not have to have insulation. It's better and cheaper. Lightning protection works this way too. Just make sure the wire is adequate cross-section that can withstand short pulse of high current.

Edited June 23, 2013 by ABCer

[retell]

I may be wrong, but a metal rod is not adequate. A sheet of copper minimum 2 ft x 2 ft with a copper wire bolted on with two copper washers buried in about 1 m deep ground will give a better conductivity. If in the place close to moisture -better still.

BTW wire does not have to have insulation. It's better and cheaper. Lightning protection works this way too. Just make sure the wire is adequate cross-section that can withstand short pulse of high current.

if you are commenting on mmy reply i meant a steel pipe with the earth wire trough it all the way to the bottom and up again so you use the steel pipe only for getting the wire in deep in the ground , and 1 meter is a bit short in my opinion , also putting it close to moisture is fine as long it is not your sewage weel than the copper will be gone pretty fast

[taninthai]

Water, if distilled or deionized, is an insulator.

It does NOT conduct electricity.

BUT

Impure water does conduct very well.

All tap water has salts and other impurities

and thus is a good conductor.

JFYI

ah above we have someone that knows what there talking about.

Crossy yes it's the metal hoses and taps or anything metal that is the danger,as said the pic in the op is all plastic so a lot slimmer chance especially if there was a breaker in the unit aswell that would trip or burn out if the water hit the wiring.

Of coarse you do really want full protection from a Ecs and earth though

[lockman]

Thai's thought I was crazy with what I required for grounding this house and that everything had to be full 3 wire runs all behind a 3 phase safety cut breaker, and surely stupid when I added a detached garage with even more grounds. Myself I like lots of grounds, even if overkill. But we've had huge surges from the power lines due to lightning hitting close by. Had a few surge suppressors with MOV's smoked while power company transformer blew apart. There is absolutely no substitute for proper earth grounding.

[RigPig]

So I see we have some knowledgeable people here and a lot of people that are maybe not misinformed but who know enough to be dangerous.

So here is the trick question.....WHY DO WE NEED A GROUND / EARTH?

And before you go off, think about this, 80% of electrocutions happen through the earth system, if we didn't have an earth system 80% of electrocutions wouldn't happen.

Why doesn't the bird sitting on the bare aerial wire that's alive get electrocuted?

Why did we use to use ISOLATING TRANSFORMERS on building sites before Earth Leakage Circuit Breakers became common place?

There is a difference between a voltage operated ELCB and a current operated RCD they are not the same as one poster already mentioned.

Food for thought huh. So why do we have a ground? It would be a lot safer without one...or would it.....

Oh and one other thing, how many earth rods should you have?

Also it is the depth not how much metal that you have in contact with the ground, the deeper you go the more moist the soil is, wetting the surface makes little or no difference whatsoever, the moisture at a particular depth is what creates the consistency in the electrical connection. It is no good having moisture on the surface if it doesn't contact the moisture at depth which is where the return to the transformer / generator is.....

Why should you join the neutral link and earth link together at the main distribution board (It's called an MEN point).

Have fun with this..... it's meant to be for education

[RigPig]

OK people, enough!!

RCDs and RCDBs do NOT need a ground to function, the old (very old) voltage operated ELCBs did, but I've never seen one in Thailand and they are illegal in most Western countries too, not made any longer.

The term 'ELCB' when used today is normally referring to an RCD.

And for those who want to know how an RCD works: http://en.wikipedia.org/wiki/Residual-current_device

TRUE but this does not negate the reason for having a functioning Ground / Earth system. RCD's do fail all be it rarely, you are also relying on the installer to have connected it correctly.

[RigPig]

Most of el. appliances in Thailand are sold with a two pin plug, which is A (active) and N (neutral).

Unless the appliance states: "Double insulated. Do not Earth", it is UNSAFE!

Now, if your appliance has three pins - does not mean you are safe. The Earth wire must be enacted in your socket (plug in point on the wall)

9 ot of 10 chances it is NOT!

Here is an easy safety check anybody can (MUST) do at home:

Get a 230-240V el. bulb (the usual incandescent type - with hot filament) fixed in a normal patron with two insulated wires connected to patron's A and N

points. The wires should be about 20-30 cm long. Cut off insulation at the tips of each wire about 1-1.5 cm. Holding at the insulation!!! stick in the bare wires into the wall socket.

If the wall socket has two points only - there is no Earth. Replace if you want to be SAFE.

If the wall socket has three points (holes) - one is A one is N one is E.

Stick bare wire ends into A and N - the lamp must be 'ON".

Stick the bare wire ends into A and E - the lamp must be 'ON'.

Stick the bare wire ends into N and E - the lamp must be 'OFF'

Remember - three combinations must be performed on each plug point.

Anything not like described above - NOT SAFE. If the room is yours - call electrician and REWIRE. Costly!

If you are renting - demand the owner does REWIRING. If he refuses - move or take a risk, - up to you, as Thai say...

Have a good life!

The rules above are for Australia. This is TITs. They may have a "Safety First" sticker instead of compliance with Aus. safety rules. Don't remove the sticker and cross your fingers. It helps...

Alternative test you can try: Stick the bare wire ends into your TITS. If the lamp goes 'ON' - you are HOT!!!

As you say these are Australian rules, I have carried surveys throughout Asia and each country is different. As the existing wiring goes ELCB's do not work here unless you fit an Isolating transformer and then a separate earth line. The power supply coming into domestic property has no earthing and as a previous writer says the safety T Cut are for overload and give little protection to the human body. There is little you can do here to make showers safer other than keep isolating switches out of the bathroom and water away from the unit. Best of luck.

I think you will find that ANY domestic supply does not have earthing, that is provided on the consumer side i.e. driving an Earth rod.

Australian rules are the most stringent in the world and for good reason. If you follow them you will have VERY few problems, only stupidity can win.

[RigPig]

Unsafe and dangerous – need both earth and ELB. A proper earth is connected to three long earth spikes, my Thai electrican told me, when installing earth in the new house I was building. The earth connection is underground, so we don't see a wire coming out from the house. Of course he also installed ELB's.

WRONG, you don't need 3 rods just one deep one will work better, the 3 rod thing comes from a different form of grounding often used in places like Russia. Joining ground rods together to make one potential rod doesn't work unless the rods ar more than 2 metres apart anyway. It's the depth that counts.....

[RigPig]

The black surface mounted double pole isolator will only act as a switch to isolate the appliance . What I have found is that the earth wire attaches from inside the HWU and then goes outside and is bolted to a copper earth stake which is bashed into the ground to provide a path of lest resistance for the fault current to escape to . Look for a single ( hopefully green in colour) coming out the rear or bottom of your HWU. Aussie sparky in Thailand.

As an Ausse sparky you should know better, the ground rod should be connected to the switchboard and the neutral and earth bars MEN'd, the HWU should be grounded at the switchboard. Don't confuse equipotential bonding with earthing they are 2 different things. Not trying to be a smart A just be more specific, if grounding isn't done properly it can become a bigger death trap

[RigPig]

forgot to tell , since my roof is a steel welded construction i grounded the steel beams at several points and connected the ground wires from wall sockets showers etc to the beams

So your grounding relys on the "mechanical" connection to the roof trusses instead of an "electrical" connection at the switchboard, don't get in the wrong place at the wrong time (when there is a fault) you'll cope it!!

[RigPig]

I may be wrong, but a metal rod is not adequate. A sheet of copper minimum 2 ft x 2 ft with a copper wire bolted on with two copper washers buried in about 1 m deep ground will give a better conductivity. If in the place close to moisture -better still.

BTW wire does not have to have insulation. It's better and cheaper. Lightning protection works this way too. Just make sure the wire is adequate cross-section that can withstand short pulse of high current.

WRONG oit is the depth that counts as explained above, don't confuse lightning protection with grounding or equipotential bonding they are all 3 separate issues and are (should be) dealt with accordingly. You can combine sometimes but must do this correctly.

[RigPig]

Anyone know what an Earth Loop Impedance test is? This is the ONLY correct way to know that your grounding / Earthing system is adequate.

GOOD LUCK!!!