Made A Diagram Of The House Wiring.

[Kwasaki]

Briefly I bought an RCB before leaving for England, and I took it for granted at the time the electrics would be installed OK, anyway they did a typical Thai job on it.

On the whole it wasn't too bad I guess but had to earth things quickly and I am going to improve on it by running wire from temporary earthed appliances to the earth bar in the Distribution box and then a 10mm earth wire to a grounding earth rod also will add another rod.

The red wire in the diagram is a grey one and the black as neutral, which I prefer as black in UK is common as a neutral.

House electric 2.bmp

Edited October 2, 2011 by Kwasaki

[Crossy]

Actually doesn't look too bad by Thai standards.

A few thoughts.

Do the '60A safety breakers' on your aircons have overload protection (post photos if you're not sure)?

What size is the cable feeding 'Area 1' on the 32A breaker?

Is your supply 5/15 or 15/45?

EDIT. Is the unfused knife switch one of those pinkish coloured 'Chang' brand ones, if so they do have space for fuses although often bridged with something less likely to 'blow'

[Kwasaki]

Actually doesn't look too bad by Thai standards.

A few thoughts.

Do the '60A safety breakers' on your aircons have overload protection (post photos if you're not sure)?

What size is the cable feeding 'Area 1' on the 32A breaker?

Is your supply 5/15 or 15/45?

EDIT. Is the unfused knife switch one of those pinkish coloured 'Chang' brand ones, if so they do have space for fuses although often bridged with something less likely to 'blow'

I was looking forward to your responses Thanks.

1. The 60 amp safety breakers I read were just on / off isolator switches, seeing as there feeding air-con I was not overly worry about them, I would like to get them into the Dist box on a MCB at some stage.

2. As well as ' Area 1 ' all feed cables in the house are 2 x 4mm white 70c etc etc.

2 x 2.5mm for switches and lights, I haven't got round to seeing how they are all joined in the ceiling yet, but no wire seem to get warm on supply to say the microwave for cooking on full power setting with a grill going as well.

3. The supply 5 / 15 or 15 / 45 you have me stump on that all I know is the house before it floode and fell down was on 5amp and the family next door are all on 5amp, we pay a bit extra for 15amp, and you have to pay a lot more if you want 3 phase, which I cannot see that we are in need of.

4. A Chang knife isolator it is, yes, white ceramic handle and a pinky brown plastic with a cap casing with fuse written on it, the cap has a metal sprung type metal hook afair, which I think you are reffering too, and yes only lightning would melt that but it doesn't seem to have any connection to anything, when you take it off it exposes two screws each side at the bottom which are the supply to the house etc.

Regards K.

Edited October 2, 2011 by Kwasaki

[Kwasaki]

I was misleading putting 60amp safety breaker, only the the 2 pole MCB's are 60amp on the cover they say National Brakers inside read 30amp safety breaker, HB type, Cat No. BS1113YT, 30amp, 2PIE, AC 240V, 1500amp.

[electau]

Consumers mains 10sqmm 2 core.

Colour codes. Black is line or active, White or grey is neutral. Retain this colour code.

2 pole knife switch should be replaced with a 50 or 63A 2 pole MCB.

The 4sqmm circuits should be protected by 32A MCBs

The 20 amp shower heater should be protected by a 25A or 32A MCB 4 sq mm.

Protection of socket outlets should be 20A wired in 2.5sqmm. RCD protected.

Shower heater area 4 should be protected by a 20A MCB wired in 2.5sqmm.

You will have DSBs ( load centres) in each of the Areas 1 to 6?

The 60A and 30A " safety breaker switch" are MCBs with a fault current rating of 1.5kA. used as an equipment isolating and protective device.

Earthing. All exposed conductive parts of electrical equipment must be earthed to the earth bar not to the main earth electrode.

The main earth is run from the main earth bar to the earth electrode. Main earth minimum 4sqmm.

All other earth conductors 2.5sqmm.

Earthing of steel framework minimum 4sqmm to main earth bar.

Electrical equipment means socket outlets, heaters, airconditioners etc.

The earthing arrangement at present is TT or direct, therefore all final subcircuits must be RCD protected.

Would recommend that the MEN system be implemented ( link at main neutral link to earth bar) then only socket outlets require RCD protection. Otherwise retain the TT system.

Install the neutral link on the line (supply) side of the main switch.

　

[Crossy]

Would recommend that the MEN system be implemented ( link at main neutral link to earth bar) then only socket outlets require RCD protection.

Do NOT do this under any circumstances unless you KNOW that MEN has been implemented in your village!! Leave it as TT, most circuits are RCD'd anyway, moving the aircons to the protected side of the 60A RCD would improve safety somewhat.

Electau, examine what will happen in the event of an open neutral between you and the Tx if yours is the only N-E link other than the one at the Tx.

Agree with the replacement of the knife switch.

[electau]

Would recommend that the MEN system be implemented ( link at main neutral link to earth bar) then only socket outlets require RCD protection.

Do NOT do this under any circumstances unless you KNOW that MEN has been implemented in your village!! Leave it as TT, most circuits are RCD'd anyway, moving the aircons to the protected side of the 60A RCD would improve safety somewhat.

Electau, examine what will happen in the event of an open neutral between you and the Tx if yours is the only N-E link.

Agree with the replacement of the knife switch, but since the home is already wired there's little point in reducing the CSA of the existing wiring.

The MEN link was only a recomendation, Yes a risk assessment should be carried out first and be subject to PEA approval. As this is a village electrical installation the TT is preferred. MEN connections require polarity testing which is unlikely to be carried out by the person connecting the installation to supply.

[electau]

Installing an MCB will protect the load side the 6 sqmm and 4sq mm conductors to the line side of the protective devices for airconditioners in the event of short circuit between L and N.

Service fuses are generally not fitted to protect consumers mains in Thailand and fault levels would probably be low ie. less than 1.5kA. That 2 pole knife switch is unfused.

Next will the source of supply be able to accomodate the peak load of the residence? The max demand what is it in amps? Peak load is less than the calculated max demand.

[Crossy]

No problem Mate

It's important to remember that this board is populated by enthusiastic DIYers who may not fully understand the ramifications of what they're doing (exactly the type of people we're trying to discourage in the UK [and I assume Oz too]).

In the case of not knowing exactly what's installed (I like to actually look) we should recommend the lowest common denominator that ensures a reasonable level of safety without introducing potentially hazardous situations.

Keep up the good work, it's always nice to have alternative opinions and solutions

[electau]

No problem Mate

It's important to remember that this board is populated by enthusiastic DIYers who may not fully understand the ramifications of what they're doing (exactly the type of people we're trying to discourage in the UK [and I assume Oz too]).

In the case of not knowing exactly what's installed (I like to actually look) we should recommend the lowest common denominator that ensures a reasonable level of safety without introducing potentially hazardous situations.

Keep up the good work, it's always nice to have alternative opinions and solutions

Thanks Crossy, the main issues as I see Thailand is short on are 1, Earthing, 2. Circuit protection and 3. Voltage drop on circuits.

[Kwasaki]

Just to clarify a few points:- My RCB as I call it is a Ground fault circuit interupter, with a trip of 0.03 - 0.02 secs and with a sensitivity turn switch, 5A, 10A, 20A, 30A, & direct.

It is on 20A. OK ???

The test I did, I will try to explain the best I can :- power off at knife switch, wire connected to neutral side of knife switch, disconnected wire from ground rod, multimeter set on ohms and probes attached.

To explain my small meter it has ohms meter readings 0 to an infinity sign, just before the infinity sign 600K it read from the 0 just pass the 1K at 1.25.

Then the AC/DC meter has a reading of 0 to 10 has a 10 v, 50v, 500v, and 1000v. With the netrual probe on the neutral wire fro the knife switch and the positive wire on the ground rod, on the 10 volt switch setting it just wacked over to 10, on the 50 volt setting it read from 0, 4 tenths towards the 1 on the 1 to 10 scale, if that makes any sense.

On the shower thread you said it should have no current but it seems to have. ????

( Crossy ) Is your supply 5/15 or 15/45? .......Ques.......Don't know, is it important..

This Thai board is full of Enthusiastic DIYers ( exactly the type of people we're trying to discourage in the UK ). Ans. We don't much choice here though do we.

( electau ) Colour codes. Black is line or active, White or grey is neutral. Retain this colour code.....Ans. Sorry don't want to do that I like it the way it is.

30A " safety breaker switch" are MCBs, isolating and a protective device.......Ques.....So this is a good thing to have untill I get things sorted out.

Once again thanks for your help.

[Kwasaki]

First diagram again then a diagram of what I intend to do to improve things.

House electric 2.bmp

House electric revision.bmp

Edited October 6, 2011 by Kwasaki

[Crossy]

Just to clarify a few points:- My RCB as I call it is a Ground fault circuit interupter, with a trip of 0.03 - 0.02 secs and with a sensitivity turn switch, 5A, 10A, 20A, 30A, & direct.

It is on 20A. OK ???

The test I did, I will try to explain the best I can :- power off at knife switch, wire connected to neutral side of knife switch, disconnected wire from ground rod, multimeter set on ohms and probes attached.

To explain my small meter it has ohms meter readings 0 to an infinity sign, just before the infinity sign 600K it read from the 0 just pass the 1K at 1.25.

Then the AC/DC meter has a reading of 0 to 10 has a 10 v, 50v, 500v, and 1000v. With the netrual probe on the neutral wire fro the knife switch and the positive wire on the ground rod, on the 10 volt switch setting it just wacked over to 10, on the 50 volt setting it read from 0, 4 tenths towards the 1 on the 1 to 10 scale, if that makes any sense.

On the shower thread you said it should have no current but it seems to have. ????

( Crossy ) Is your supply 5/15 or 15/45? .......Ques.......Don't know, is it important..

This Thai board is full of Enthusiastic DIYers ( exactly the type of people we're trying to discourage in the UK ). Ans. We don't much choice here though do we.

( electau ) Colour codes. Black is line or active, White or grey is neutral. Retain this colour code.....Ans. Sorry don't want to do that I like it the way it is.

30A " safety breaker switch" are MCBs, isolating and a protective device.......Ques.....So this is a good thing to have untill I get things sorted out.

Once again thanks for your help.

Ah, you have an analogue meter (got a needle), this is good, less likely to get confused by weird voltages.

Does it have a single ohms range? If not the multiplier (x10, x100, x1k) is important, read ohms off the weird backwards, non-linear scale and multiply by the range. I've never tried reading ground impedance using a regular meter (I have the proper kit), so anything you read is, well, open to interpretation and potential error.

A few volts N-E is not a problem, but could confuse your meter which is why the proper kit is preferred, sadly it's not cheap, my installation tester cost the best part of USD 1k

Your supply meter will be marked 5/15 or 15/45, if you have the former it's probably been blown into next century

Your RCD is fine on the 20mA range, bypass should be avoided as it removes all protection.

[Kwasaki]

Just to clarify a few points:- My RCB as I call it is a Ground fault circuit interupter, with a trip of 0.03 - 0.02 secs and with a sensitivity turn switch, 5A, 10A, 20A, 30A, & direct.

It is on 20A. OK ???

The test I did, I will try to explain the best I can :- power off at knife switch, wire connected to neutral side of knife switch, disconnected wire from ground rod, multimeter set on ohms and probes attached.

To explain my small meter it has ohms meter readings 0 to an infinity sign, just before the infinity sign 600K it read from the 0 just pass the 1K at 1.25.

Then the AC/DC meter has a reading of 0 to 10 has a 10 v, 50v, 500v, and 1000v. With the netrual probe on the neutral wire fro the knife switch and the positive wire on the ground rod, on the 10 volt switch setting it just wacked over to 10, on the 50 volt setting it read from 0, 4 tenths towards the 1 on the 1 to 10 scale, if that makes any sense.

On the shower thread you said it should have no current but it seems to have. ????

( Crossy ) Is your supply 5/15 or 15/45? .......Ques.......Don't know, is it important..

This Thai board is full of Enthusiastic DIYers ( exactly the type of people we're trying to discourage in the UK ). Ans. We don't much choice here though do we.

( electau ) Colour codes. Black is line or active, White or grey is neutral. Retain this colour code.....Ans. Sorry don't want to do that I like it the way it is.

30A " safety breaker switch" are MCBs, isolating and a protective device.......Ques.....So this is a good thing to have untill I get things sorted out.

Once again thanks for your help.

Ah, you have an analogue meter (got a needle), this is good, less likely to get confused by weird voltages.

Does it have a single ohms range? If not the multiplier (x10, x100, x1k) is important, read ohms off the weird backwards, non-linear scale and multiply by the range. I've never tried reading ground impedance using a regular meter (I have the proper kit), so anything you read is, well, open to interpretation and potential error.

A few volts N-E is not a problem, but could confuse your meter which is why the proper kit is preferred, sadly it's not cheap, my installation tester cost the best part of USD 1k

Your supply meter will be marked 5/15 or 15/45, if you have the former it's probably been blown into next century

Your RCD is fine on the 20mA range, bypass should be avoided as it removes all protection.

Yes the little meter has a needle, when the turn switch is on ohms setting with the 2 probe together the needle moves from the ' 0 ' AC/DC side over to the ' 0 ' on the far side of the scale, then the ohms scale reads from ' 0 ' to 1K and on up to 600K and the infinity sign.

When testing a battery the turn switch can be set to DC on 5v, 25v, 250v, 500v.

When testing AC current the turn switch can be set on 10v, 50v, 500v, 1000v.

It has 3 read out scales from ' 0 ' to 10, ' 0 ' to 50, ' 0 ' to 250. it has another scale which reads ( -1 to 27+ db ) maybe for sound, don't know.

As I wrote :- I placed a 4mm wire cable into the knife switches neutral then ran it out to near the grounding rod the meters neutral probe was clamped to the wire, the meters positive probe was clamped on the ground rod, with the meter set on 10 volt AC setting it just wacked over from 0 to 10 scale, set on the 50 volt AC setting it read from 0 to 50 scale 12.5volts.

Checked the Street supply clock meter with the bill number and we have a 15/45amp supply.

As for the RCD, I was going to throw out the knife switch and connect the incoming feed directly to the RCD.

I have done another drawing on post 12 and when you get time if you and ' electau ' as well could give it a look and comment on what I propose to do, that will be great, thanks.

Kind Regards K

Edited October 7, 2011 by Kwasaki

[Litlos]

Just a few ideas based on some experience with Thai electrics and info provided. Personally I would retain the knife switch as a pure isolation point. I like visible air gaps for isolation in electrics. However would relocate all circuits to the downstream side of the RCD. Just an observation that you are using perhaps a smaller gauge of wire than what is required between the isolation and RCD's etc. Maybe 10mm2 for the whole front end. Also check all the terminal screws are tight. Sometimes the sparkies do the connections before the morning noodles and have no strength, result not really tight terminals and wiring with some peculiar characteristics.

With the earth stakes are they firm or loose? Try giving them a wriggle. I have helped friends resolve their electrics problems by relocating the earth stake to a damp area and ensuring it is firm in the ground and all of a sudden the tingles disappear.on earthed appliances. Also resolved by placing the wifes favourite pot plant alongside earth stake and told to water both regularly.

Cheers

[electau]

You should retain the colour codes as these comply with Thai standards.

The use of a RCBO as a main switch complies with Thai practice.

Earthing, all protective earth conductors from electrical equipment should be run to the earth bar.

　

Edited October 11, 2011 by electau

[electau]

The terminology( IEC) can be confusing.

RCD is any protective device that operates on residual current in mA ( earth leakage).

RCCB is a residual current circuit breaker with no overcurrent and short circuit protection. It operates only on residual current in mA.

RCBO is a device that has over current, short circuit and residual current protection.

The generic term is "Safety Switch".

RCCBs must be provided with short circuit protection on the line ( supply side).

10mA units must operate in less than 0.04 secs, 30mA in less than 0.2/.3secs.

The US NEMA term is GFCI, ground fault circuit interupter.

Thai RCBOs may have settings of 5mA/10mA/15mA/20mA and direct. This last position disables the earth leakage functions. These do not comply with IEC standards but comply with TIS and NEMA standards.

[Kwasaki]

The terminology( IEC) can be confusing.

RCD is any protective device that operates on residual current in mA ( earth leakage).

RCCB is a residual current circuit breaker with no overcurrent and short circuit protection. It operates only on residual current in mA.

RCBO is a device that has over current, short circuit and residual current protection.

The generic term is "Safety Switch".

RCCBs must be provided with short circuit protection on the line ( supply side).

10mA units must operate in less than 0.04 secs, 30mA in less than 0.2/.3secs.

The US NEMA term is GFCI, ground fault circuit interupter.

Thai RCBOs may have settings of 5mA/10mA/15mA/20mA and direct. This last position disables the earth leakage functions. These do not comply with IEC standards but comply with TIS and NEMA standards.

How come the 5 / 15amp and a 15 / 45amp supply ?

[Crossy]

How come the 5 / 15amp and a 15 / 45amp supply ?

It's down to the maximum current available from the supply, 5/15=15A, 15/45=45A and the rarer 30/100=100A most are fused at about 30% overload so you can actually get near 505 overload before anything trips.

5/15 also attracts a lower tariff if your usage is very small (or free if even smaller).

Most medium size homes have a 15/45 which is more than adequate unless you're a massive user.

[electau]

The meters are rated at 5/15, 10/45, 30/100. The first figure is the test current, the second is the continuous full load rated current.

These meters have a high overload capacity. In Thailand service HRC fuses are generally not installed on the line side of the meters, Service fuses are for short circuit protection only. They are not for overload protection. They are installed by the supply authority.

They also provide a point for electrical disconnection of supply.

[Kwasaki]

How come the 5 / 15amp and a 15 / 45amp supply ?

It's down to the maximum current available from the supply, 5/15=15A, 15/45=45A and the rarer 30/100=100A most are fused at about 30% overload so you can actually get near 505 overload before anything trips.

5/15 also attracts a lower tariff if your usage is very small (or free if even smaller).

Most medium size homes have a 15/45 which is more than adequate unless you're a massive user.

The meters are rated at 5/15, 10/45, 30/100. The first figure is the test current, the second is the continuous full load rated current.

These meters have a high overload capacity. In Thailand service HRC fuses are generally not installed on the line side of the meters, Service fuses are for short circuit protection only. They are not for overload protection. They are installed by the supply authority.

They also provide a point for electrical disconnection of supply.

Thanks for that, interesting.

To be safe I have to get the supply authority out to disconnect so I can connect the live from the knife switch to the RCB, there is no cut off in the road.

Litlos said :- Personally I would retain the knife switch as a pure isolation point. I like visible air gaps for isolation in electrics.

Where as I take it that knife switches are not particularly a good idea because it is inside my house not outside.

Don't know why but maybe because of a serious short out on a wires coming into the house could cause fire or other damage.

[Crossy]

Where as I take it that knife switches are not particularly a good idea because it is inside my house not outside.

Don't know why but maybe because of a serious short out on a wires coming into the house could cause fire or other damage.

I too would retain the knife switch unless it is damaged and presenting an actual hazard, one more point of isolation can do no harm.

You should be able to get the correct fuses to fit in the fuse enclosure of the switch, but only fuse the live side, use a solid link in the neutral side.