No Gfci Sockets At Home Pro

[Crossy]

Perfect! ...and 10mA or 30mA for outside use?

Entirely up to you but you may find 10mA are a little enthusiastic for use with equipment that is in use outdoors, particularly things like water pumps which are in a damp environment.

The UK regs consider 30mA adequate for all but a few specific applications, so I'd use them.

[powderpuff]

In a rented condo I installed a hot water heater & a pump. After talking to Crossy I went to my local supply store & asked the owner if she had RCCB. She sure did. So I bought this & wired it up. <BR><BR>Installed & each appliance had it's own breaker.

Edited March 10, 2011 by powderpuff

[Morakot]

you can get a beastie called an RCBO which will replace the standard MCB (breaker) and provide both overload and shock protection.

(Sometime later, a new question)

Where would be a good place to locally buy RCBOs and at what estimated costs replacing the MCBs in my CU?

Edited July 24, 2012 by Morakot

[Crossy]

Depends upon the manufacturer of your distribution board, if it's Square-D with plug-in MCBs then HomePro have RCBOs for about 1400 Baht (IIRC). For other manufacturers you will need to visit your local wholesale outlet, they may have to order

Visit the manufacturer's website to get part numbers, pictures etc.

[Morakot]

Depends upon the manufacturer of your distribution board, if it's Square-D with plug-in MCBs then HomePro have RCBOs for about 1400 Baht (IIRC). For other manufacturers you will need to visit your local wholesale outlet, they may have to order

Visit the manufacturer's website to get part numbers, pictures etc.

Thank you kindly, Crossy!

I think it's a Square-D board, looking at the logo on the case; the MCBs look like plug-in.

Would you, or anyone else, be able to comment about the earthing system from these pictures. I'm not inspired with confidence after having inspected several dozen wall sockets and found that none of them had the earth wires actually connected.

[Crossy]

Ah, the classic Thai NONE grounding system. The brass (earth) bar at the top should be full of green wires

Is the black wire at the left end of the earth bar connected to it, any idea where the other end goes? Could be that ground is brought to the box but not distributed around the apartment.

[electau]

If the earth conductor has been brought into the switchboard with the sub mains it should be green or green /yellow but this is not guaranteed, the others wil be the L line which should be black and the N neutral which should be white.

The earth conductors should terminate on the earth bar. The earth terminal of all socket outlets should have an earth conductor connected to them.

RCD/RCBO will provide protection from earth faults.

If the installation is typical of most Thai electrical installations, there may be NO effective earthing at all.

[Pib]

Like Crossy mentioned is there any incoming wire that is conneced to that top bar. I blowed the picture up and the more I look at it I don't think there is any incoming wire to the bar..an incoming wire that should be your Earth ground...but it hard to tell with the picture resolution. Your residence could be just like my mother-in-laws house built about 30 years ago....two incoming wires (Live and Neutral) and then just bunch of outgoing 2 wire connections throughout the house. Summary: no Earth ground.

[Morakot]

Thank you gentlemen!

I was suspecting this and it's nice to have certainty now. For background information the house was built less then a decade ago.

So would it make sense to proceed in the following way:

1. To check were the black wire at the left end of the earth bar goes; if it goes nowhere, then to install a 2m earth rod;
   
2. To connect the green wires -- that most installed outlet cabling throughout the house already has -- onto the earth bar
   
3. Measure impedance at each outlet to check internal earth wires (and with it the existing or newly installed earth rod)
   
4. To replace the MCBs with RCBOs
   

Edited July 25, 2012 by Morakot

[Crossy]

In the absence of an earth-resistance meter or loop-impedance tester you can do a quick-and-dirty earth test with a 15W light bulb (filament lamp).

Carefully connect one end of the lamp to your earth bar, the other end should go to a live point via some form of switch. Remove all vulnerable persons from the house just in case. Turn on the switch. The lamp should light if there is a half decent earth.

[Morakot]

In the absence of an earth-resistance meter or loop-impedance tester you can do a quick-and-dirty earth test with a 15W light bulb (filament lamp).

Carefully connect one end of the lamp to your earth bar, the other end should go to a live point via some form of switch. Remove all vulnerable persons from the house just in case. Turn on the switch. The lamp should light if there is a half decent earth.

OK great! Many thanks.

[Morakot]

In the absence of an earth-resistance meter or loop-impedance tester you can do a quick-and-dirty earth test with a 15W light bulb (filament lamp).

Carefully connect one end of the lamp to your earth bar, the other end should go to a live point via some form of switch. Remove all vulnerable persons from the house just in case. Turn on the switch. The lamp should light if there is a half decent earth.

OK, I've tested it with a 25W light bulb (filament lamp) connecting it to the earth bar and a live point from a socket.

When turned on, it tripped the MCB. What is happening here?

Edited July 27, 2012 by Morakot

[Crossy]

Hmmm, do you have a separate RCD box (often marked Safe-T-Cut) that tripped?

If not and you managed to trip one of those MCBs with a 25W lamp are you sure the lamp was wired correctly?

Either way, looks like there is at least a usable ground in the box

[Morakot]

Hmmm, do you have a separate RCD box (often marked Safe-T-Cut) that tripped?

If not and you managed to trip one of those MCBs with a 25W lamp are you sure the lamp was wired correctly?

Either way, looks like there is at least a usable ground in the box

Thanks Crossy.

I don't think there is a separate RCD box. What tripped is one of the MCBs in this box (not the main one); see picture.

The lamp was brand new and worked properly, before I disconnected one wire and attached it to the earth bar.

I am quite amazed --or rather puzzled-- about this set up. How can one have a functioning earth system right into the CU, wired the place mostly with three wire cables, but didn't bother to connect the earth wires to the sockets and the CU? Is this a normal level of complacency, I wonder.

Edited July 27, 2012 by Morakot

[lopburi3]

I do not see any three wire cables into the circuit box. Are you sure you have (mostly) three wire electric lines? Am sure the ground buss is near ground as appears attached to metal box and that would be mounted into the cement. But nothing looks like box or wires were ever intended to be 3 wire ground system. But admit can not see well enough to be sure if they cut the ground under outer wrap. Or do you mean there is a separate green wire run that does not currently go into the circuit box? I can not make out any green in the box.

[Morakot]

I do not see any three wire cables into the circuit box. Are you sure you have (mostly) three wire electric lines? Am sure the ground bar is near ground as appears attached to metal box and that would be mounted into the cement. But nothing looks like box or wires were ever intended to be 3 wire ground system.

From my last inspection: Almost all cables for each socket (on each floor) are 3 wire cables; all these cables go into the attic. Yes, the bundle of cables that comes down from the attic into the CU looks like only 2 wire cables.

I haven't been able to look into the attic yet. Why and how the cables change (from 3 to 2 wires) is not clear to me either. I'll post some more pictures if people are interested.

[eraymos]

Not to get away from Morakot's problems, but how does my CU look? Crossy, Electau do you see any problems or safety hazards?

[Crossy]

Not to get away from Morakot's problems, but how does my CU look? Crossy, Electau do you see any problems or safety hazards?

Apart from the incorrect colour code, far too neat for its own good. But don't worry, a couple of additions by local sparkies will bring it up to standard.

You have two earth rods?

No MEN connection, assume your area is still TT.

Neutral from your SPD has no number (OK getting desperate), by the way, where is the live for the SPD connected to? If you are TT connected you should be providing SPD L-E and N-E (some would want L-N too) for complete protection.

[eraymos]

Oddly enough, all the work was done by the village sparky. I think he did a great job on the CU and the whole house. There are no wires outside of conduits and all wires are connected with wire nuts and taped. There is a MEN connection. If you look very close you will see that one of the two 16mm2 ground wires go to the neutral bar (behind the SPD neutral). The live from the SPD is spliced to the 35mm2 incoming live as there was no room to connect to the main breaker. As for the colors, couldn't find enough black wire to do the whole job. Red as live, white neutral, and green for ground is easy to understand.

[Morakot]

Eraymos's CU looks neat!

I have figured out the changeover from 3 to 2 wire cables in my house. All 3 wire cables for the sockets lead into the attic and terminate there, with the L and N wires being tapped (without terminal connectors [!]) to L and N wires of new (2 wire) cables that connect to the CU. Most earth wires of the socket cables --as it appears-- are connected to each other and feed into a separate single wire which in turn is connected to the earth bar in the CU.

My question is would it makes sense to replace the MCBs with RCBOs, with this single earth wire set up, or should separate individual earth wires connect to the bar in the CU, before I do anything else?

Edited July 30, 2012 by Morakot

[Crossy]

At least you appear to have earthing, what's been done is most definitely not best practice but is unlikely to be unsafe, leave it alone unless you really want to start pulling more green wire around.

Install your RCBOs first, they will make a significant improvement to the safety of the installation, fettle the earthing as the second job.

[Morakot]

At least you appear to have earthing, what's been done is most definitely not best practice but is unlikely to be unsafe, leave it alone unless you really want to start pulling more green wire around.

Install your RCBOs first, they will make a significant improvement to the safety of the installation, fettle the earthing as the second job.

Thanks Crossy!

[Morakot]

This is a sort of "Before & After", as I am happy to report that another household wiring in Thailand is (slightly) safer now. As one can see, there is now a RCBO instead of a main breaker. Thank you for all the input.