Question Regarding Electricity Supply

[khaan]

I have anxieties about the electrical switchboard in my new apartment because one of the switches (relating to the water heater in the shower ) keeps " tripping " sporadically about once or twice every day even when the shower heater is not being used. I am not sure what the proper terminology for this switch box is but it is similar to the one in the picture below although this is not the actual one in my apartment.

The maintenance man from the apartment building has already looked at it a few weeks ago after I reported it then and had a look at the switch and for a while everything was okay. But now the same fault is occurring again.

The reason I am so anxious is because it is only the switch relating to my shower which is the one that keeps tripping and so I keep wondering whether this is a signal that the water heater itself is malfunctioning even though it is brand-new because I'm in a new apartment building .

You read so many stories in Thailand of people being electrocuted in the shower that I think it's better to be safe than sorry which is why I decided to post this question.

In my switchboard are 4 single switches and 1 double am from left to right they are labelled as being

1 the shower

2air-conditioner

3 electrical sockets

4 lights

The double switch at the right side of the panel doesn't have any labeling at all.

I am just wondering if anyone here with a knowledge of electricity can tell me whether I am worrying unnecessarily or whether my anxiety is indeed founded and that it is the shower heater itself which is showing signs of some fault which is causing the switch in the box to keep tripping?

Edited November 4, 2011 by khaan

[h90]

It is dangerous!!

I would test first: is 1 really the shower?

Drop it and check if the shower is without electric or not. The label might be wrong.

If yes, drop the other one and check if really everything else is without electric.

Do you have a meter and pay per your electric usage?

If yes does it run when you drop all switches beside the shower and don't use the shower?

Are the wires visible, or inside the wall? If outside follow them.

(the idea behind that is, maybe it isn't a technical problem, maybe your neighbor is connecting to your electric somewhere, so he can lower his bill and sometimes he uses too much so the switch is falling down)

[Crossy]

Let's move this to DIY where the sparkies live

[Crossy]

+1 for h90's instructions.

Does the breaker that is tripping have a 'Test' button? Are there any others with 'Test' buttons.

A decent photo of the actual board would be useful.

[khaan]

It is dangerous!!

I would test first: is 1 really the shower?

Drop it and check if the shower is without electric or not. The label might be wrong.

If yes, drop the other one and check if really everything else is without electric.

Do you have a meter and pay per your electric usage?

If yes does it run when you drop all switches beside the shower and don't use the shower?

Are the wires visible, or inside the wall? If outside follow them.

(the idea behind that is, maybe it isn't a technical problem, maybe your neighbor is connecting to your electric somewhere, so he can lower his bill and sometimes he uses too much so the switch is falling down)

Ok so if I select " OFF " for that particular switch on the panel and have cold showers until this matter is resolved

is that going to ensure my welfare in the meantime?

No I know 100% sure it is the shower because when the switch goes off the green light on the shower heat itself

doesn't come on and the water is cold until I go and reset switch in the panel on the wall. Only once has it

happened while I was actually having a shower which scared the shit out of me

Yes I have a meter which is in a separate meter to room in the building which the building management reads every month

and then issues a bill..

Yes there is a lot of wiring visible all over the apartment and it was just painted over.

Edited November 4, 2011 by khaan

[khaan]

+1 for h90's instructions.

Does the breaker that is tripping have a 'Test' button? Are there any others with 'Test' buttons.

A decent photo of the actual board would be useful.

I am sorry I don't have the means to take a photo of the actual board at this point

but I will try to do so.

But in the meantime no it doesn't seem to have a test button.

[khaan]

The building manager has just been to see me and he told me he needed to replace the individual switch itself which he did.

He admitted that one other person in the building had experienced a similar problem and had their switch replaced also ( which I didn't know about ) and that brand-name of the switches themselves ( IDV )didn't appear to be very high quality even though they are new. he let me smell it the old one which they took out and there was definitely a burnt smell coming from it.

So they have just finished replacing it and I'm hoping that I am now safe again

Edited November 4, 2011 by khaan

[Crossy]

Let us know how it goes, however without any form of earth leakage protection such as an RCD or Safe-T-Cut (that's the beastie with the Test button) you are still in a less than safe environment.

You should get one installed as soon as possible, a whole house unit would be easiest for the building people to install for you.

[khaan]

Let us know how it goes, however without any form of earth leakage protection such as an RCD or Safe-T-Cut (that's the beastie with the Test button) you are still in a less than safe environment.

You should get one installed as soon as possible, a whole house unit would be easiest for the building people to install for you.

Hi Crossy

Thanks very much for your replies and advice

Well your words " you are still in a less than safe environment. " arer not particularly comforting

I'm trying to work out the best way to approach this.

This afternoon I found the website for the manufacturer and it didn't surprise me that the switch boxes are made in China.

Here is their website

http://www.idvcn.net...class=55&other=

As there is no test button on my box what is the best way for me to approach my landlord about this issue?

I know the building owner very well and he a good person- a fair landlord and good business person. I think if he understood that by having used

low quality components there may be some element of danger to tenants in this building, I think he would very quickly agree to rectify it

because in fact his own son has a special bachelor pad apartment in the building which is actually right next door to mine!

Edited November 4, 2011 by khaan

[bankruatsteve]

Just some thoughts...

If the breaker doesn't have a test switch, then can probably assume that it's not an RCD. Which means that it must be tripping from overload. I don't see anything indicating the watts for your shower or amps for the breaker, but if, for example, your shower is 3.5K watt and it's on a 10 or 15 amp MCB, that's probably why it's tripping. Not sure I see the dangerous in that b/c it's doing what it's supposed to do. Anyway, if that's the case, you might be screwed unless the wires going to your shower are at least 2.5mm2. If they are, you can simply replace the breaker with 20/25 amp (RCBO better) and you should be good to go. If the wires are smaller than 2.5mm2, then it doesn't matter what you do at the CU. You would then either need to re-wire, replace with smaller shower unit (< 2Kwatt), or turn off the MCB and go with cold showers.

[Crossy]

Steve.

Looks like the breaker was faulty (Post #7).

Khan.

With no RCD you are not in immediate danger of dying it's not like having a bare wire lying around. An RCD comes into its own when you have a fault which is potentially life-threatening, it kills the power before the power kills you.

Ensuring that your water heater is correctly grounded and is protected by an RCD (which could cover the whole house) is the sensible next step.

[khaan]

Steve.

Looks like the breaker was faulty (Post #7).

Khan.

With no RCD you are not in immediate danger of dying it's not like having a bare wire lying around. An RCD comes into its own when you have a fault which is potentially life-threatening, it kills the power before the power kills you.

Ensuring that your water heater is correctly grounded and is protected by an RCD (which could cover the whole house) is the sensible next step.

Thanks again Crossy

And now I have a couple of photographs which you said yesterday could help you to comment.

Does this mean anything to you?

And you will see in one photo I turn to switch off the show you which was the faulty one.

And you can see slightly to the right and underneath the switch that had to be replaced

Is the label for the shower.

Does this too basic perhaps -I don't see any test button anywhere?

[bankruatsteve]

Looks like 32a on the shower. (?) So, scratch my thoughts. Just wondering... did the breaker replace fix the tripping problem? If so, and your shower unit is earthed properly, you probably good. (BUT - if you don't have - I think it's called "ELCB" in the shower unit (test switch, yah?) - you would be better protected with RCBO/RCD in the CU).

Edited November 5, 2011 by bankruatsteve

[Forkinhades]

Let us know how it goes, however without any form of earth leakage protection such as an RCD or Safe-T-Cut (that's the beastie with the Test button) you are still in a less than safe environment.

You should get one installed as soon as possible, a whole house unit would be easiest for the building people to install for you.

I will echo that

[khaan]

Let us know how it goes, however without any form of earth leakage protection such as an RCD or Safe-T-Cut (that's the beastie with the Test button) you are still in a less than safe environment.

You should get one installed as soon as possible, a whole house unit would be easiest for the building people to install for you.

I will echo that

I occupy an apartment in one building in a complex of three separate buildings. See the picture.

in my particular building there are about 40 apartments over eight floors.

When you say " a whole house unit " are you talking about something that would be put in the basement carpark

and could be joined to the existing electricity supply without much cost ?

or does it mean the switch boxes in every apartment would need to be changed?

Edited November 5, 2011 by khaan

[Forkinhades]

You will need a elcb/rcbo in each apartment, otherwise under fault conditions the whole block would go off

[electau]

Yes install a RCBO and make sure that the shower heater is earthed. Is there an earth conductor to your distribution board from the building main switch board?

What is the rating of your shower heater and the cable size in sqmm?

Yes, an overheating terminal in an MCB can cause the device to trip.

[Forkinhades]

Listen guys this is serious stuff, and should be left to the experts. Cable sizing is another major factor here in LOS, which can be inherent of many a fire coupled with wrong size and type of MCB. The shower must be earthed, and indeed the earth needs to be tested, to make sure it is stable and of good quality, in the UK, we would be looking at between 0.5 - 20 ohms, in practice here in LOS the readings will be much much higher, and anything over 200 (IMO, and BS7671) is considered unstable, although a reading of 1667 ohms would work with a 30 mA RCD. These devices need to be tested and on a regular basis, and not just by hitting the test switch, appropriate equipment must be used. Its your life!

[electau]

In reply to #18.

This is why RCDs are used on TT systems the earth return path through the soil is far too high for an overcurrent protective device (MCB)to operate in less than 0.4secs. 50VAC = 30mA x 1666 ohms. An RCD must operate between 50% and 100% of its rated tripping current in mA.

(Based on a 13sqmm copper clad steel electrode as a main earth at a depth of 1.2/1.8metres). Soil resistance is not a constant value.

[Forkinhades]

^ Indeed, and 95% of domestic dwellings here in LOS will be TT. The OP states that he is in an apartment block, so the earthing arrangements (If any) will have to be looked at in great detail.

(Based on a 13sqmm copper clad steel electrode as a main earth at a depth of 1.2/1.8metres). Soil resistance is not a constant value.[/color] [#quote]

In my installations, I make sure that the earthing arrangements will be less than 20 ohms. May need extra earth rods, mats etc etc.

[electau]

The apartment block may have its own transformer. Yes, the earthing arrangements would have to be verified.

One note on the 20 ohms earth contact resistance if it can be attained it would still not be low enough to trip an overcurrent device (MCB) on an earth fault in less than 0.4 seconds. However using RCDs the tripping time would be reduced to less than 0.2/0.3 seconds.

An RCD will provide superior "earth fault current" sensing and response time, compared to a conventional MCB. Hence a circuit protected by an RCD device during a fault provides suitable touch voltage protection.

Earth bonding ( equipotential bonding) reduces the effect of touch voltage also.

　

　

[Forkinhades]

The apartment block may have its own transformer. Yes, the earthing arrangements would have to be verified.

One note on the 20 ohms earth contact resistance if it can be attained it would still not be low enough to trip an overcurrent device (MCB) on an earth fault in less than 0.4 seconds. However using RCDs the tripping time would be reduced to less than 0.2/0.3 seconds.

I was only talking about RCD's

An RCD will provide superior "earth fault current" sensing and response time, compared to a conventional MCB. Hence a circuit protected by an RCD device during a fault provides suitable touch voltage protection.

Earth bonding ( equipotential bonding) reduces the effect of touch voltage also.

　

　

20 ohms is for TT systems (IMO), which would not operate any MCB's under fault in time specified

0.1 - 0.5 TNCS/TNC/TNS systems, will trip MCB's providing the cabling has been installed correctly, ie correct size and length for the job

lets keep this simple for the people trying to follow the thread

[khaan]

The apartment block may have its own transformer. Yes, the earthing arrangements would have to be verified.

One note on the 20 ohms earth contact resistance if it can be attained it would still not be low enough to trip an overcurrent device (MCB) on an earth fault in less than 0.4 seconds. However using RCDs the tripping time would be reduced to less than 0.2/0.3 seconds.

I was only talking about RCD's

An RCD will provide superior "earth fault current" sensing and response time, compared to a conventional MCB. Hence a circuit protected by an RCD device during a fault provides suitable touch voltage protection.

Earth bonding ( equipotential bonding) reduces the effect of touch voltage also.

　

　

20 ohms is for TT systems (IMO), which would not operate any MCB's under fault in time specified

0.1 - 0.5 TNCS/TNC/TNS systems, will trip MCB's providing the cabling has been installed correctly, ie correct size and length for the job

lets keep this simple for the people trying to follow the thread

And I thought learning to speak Thai was difficult?

this is all complete double Dutch to me ! But I am going to express my concerns to the owner when I see him.

But I was also thinking no matter how safe our own homes are, what about each time we stay

in a resort or a hotel in Thailand? there must be instances where they have cut corners and those of us

who are not electricians wouldn't have a clue just how at risk we might be?

[Forkinhades]

@khaan

Indeed you are right the Electrical systems in Thailand are shocking, and people have died in hotel showers. This just highlights the point that the electrics do need to be tested on a regular basis

[electau]

It is very important which earthing system is used within an electrical installation.

TT. No link between the main neutral and the main earth. RCDs/RCBOs must be used to obtain tripping times under earth fault conditions. The fault path is through the PE conductor to the earth bar and the main earth conductor and main earth electrode. The resistance is far too high for an MCB to operate under earth fault conditions.

TN-C-S or MEN system. The neutral is bonded to the earthing system. RCDs are installed as additional protection and where required by standards (AS/IEC). eg socket outlets. the fault path here is through the PE conductor to the earth bar and then through the main neutral to the transformer. Negligable current flows in the main earth conductor and this can be disregarded. The impedance off the earthing system and the L and N conductors from the transformer must be such so as to operate an MCB in less than 0.4secs. If this can not be achieved an RCD or RCBO must be used.

If the minimum sizes of conductors and protective device ratings are complied with the above will be achieved within an electrical installation.

TN-S. The only difference here from the MEN system is that an earth conductor is run directly to the transformer earth from the earth bar of the main switchboard and this is the only bond to the main earth. The main earth is the earthing of the neutral conductor. May be used where an on site transformer supplies the main switch board of a large building ot a multi tenanted building. S= separate earth

TN-C This refers to the common neutral and earthing conductor from the transformer to the main switchboard neutral link of the electrical installation.

Earthing requirements for the earthing of a transformer neutral and distribution system MEN connections are far more onerous and are generally covered by regulations of the supply authority.

Testing. Testing must be carried out before connection to supply. Earthing. Insulation, Polarity tests etc.

RCDs should be tested at least every 3months by the use of the test button on the unit. this tests the functional operation of the unit. It does not test the continuity of the PE conductor.

　

　

Edited November 8, 2011 by electau

[electau]

khaan,

One question, are the socket outlets 3 pin or 2 pin? If 3 pin are they earthed? Is the airconditioner earthed?