Live & Neutral Reversed

[emanphoto]

Went to inspect our new condo today here in BKK and did a check of all the outlets with the outlet tester my wife finally found at a home show here.

Attached is a pic of the tester. The top marked (w/arrow) indicator show correctly wired outlets. The lower marked indicator is how the whole unit (new construction) is wired.

Not believing the condo's project engineer, my wife called her electrical engineer who is doing the work for a new resort on Samui she's involved with, and he told her that because it is a German made outlet vs Thailand's electrical system/wiring, the live and neutral have to be reversed and to be otherwise would actually be incorrect. If they were Thai made outlets, then they would have wired it differently.

Now, I barely know my watts from dingle berries but this sounds odd, yet at the same time is confirmed by 2 different sources, although the condo engineer I would discount just because of who he works for.

Any other opinions on this?

[thomasteve]

The Thai 3 pin socket outlets have the live on the left side, neutral on the right and earth at the top when looking from the front.

So the live and neutral are transposed compared to the UK convention - the same may be true for the German configuration ?

[AnotherOneAmerican]

They managed to connect my house supply with live and neutral reversed (from the meter outside).

It means all the neutral wires in the house were live, no matter what position the fuse box switches were in.

Very dangerous.

[thomasteve]

They managed to connect my house supply with live and neutral reversed (from the meter outside).

It means all the neutral wires in the house were live, no matter what position the fuse box switches were in.

Very dangerous.

I also had that happen so it seems to be quite a common occurrence, probably due to both L and N being the same black colour.

[Forkinhades]

Picture of the outlet please

[emanphoto]

Thomasteve that sounds like the most likely scenario. I don't live there yet so can't take a photo and won't be back there till the next inspection on the 22nd.

But as I recall, they were configured like this one.

The Thai 3 pin socket outlets have the live on the left side, neutral on the right and earth at the top when looking from the front.

So the live and neutral are transposed compared to the UK convention - the same may be true for the German configuration ?

[Crossy]

Definitely a Thai outlet, three possibilities.

1. Outlet is wrong because it's made in Germany (unlikely)

2. Tester is wrong (possible)

3. Sparks got the wires in the wrong holes (probable)

If you have a neon screwdriver (everyone should have one) it's easy to check.

Pop the outlet off the wall, there should be three wires, black, white and green. Visually check the black (live) wire goes to the terminal marked L, white (neutral) to N and green (earth) to the E terminal (could be marked with the earth symbol). I'll put money on the problem appearing at this test.

If that's correct put your neon on the black wire (it needs to contact the copper so putting it on the screw will be easier), it should light when you put your finger on the end. If it doesn't try the white wire. If it lights on white then it could be a reversal at the board.

Time to get serious, pop the lid off the board (power off for safety).

Check the wiring inside the board, all the whites should go to a bus bar, the greens to another bar and the blacks to the individual breakers. Turn on the power and again use your neon, it should light on the breaker terminals. If it lights on the white bus it looks like a reversal on the incoming supply. Turn off and get your sparks.

After strangling him get his mate to sort it.

EDIT to our OP, well done to your good lady for spotting a device that's rarer than hen's teeth in Thailand, recognising what it was and buying it. How much was the beast?

[wayned]

Many testers available here with free shipping: http://www.aliexpress.com/wholesale?SearchText=electrical+outlet+tester&catId=0&initiative_id=

I've used them in the past and everything arrived and was in good condition except one thing . When I sent them pictures of the damaged item they credited my account immediately without return of the unit. The shipping time on items with "free shipping" is about 3 weeks but I wasn't in a hurry.

[Crossy]

The problem with 99% of the 3-light testers available on the international market is that most of the world's outlets are live on the right so a simple adaptor won't do the trick. The only exception I know of is North America (which is 110V). The Philippines is 220V and uses the US outlet, but it also uses 3-phase 3-wire with the outlets between phases, so there's no neutral per-sé (both legs are about 130V above ground).

I've found a few testers which have a lead which can have the plug replaced but the one in the OP is the first I've seen specifically aimed at Thailand.

Using a voltstick / neon screwdriver alone can give misleading results, for example it may light on a disconnected ground (by capacitive coupling).

[thomasteve]

The problem with 99% of the 3-light testers available on the international market is that most of the world's outlets are live on the right so a simple adaptor won't do the trick. The only exception I know of is North America (which is 110V). The Philippines is 220V and uses the US outlet, but it also uses 3-phase 3-wire with the outlets between phases, so there's no neutral per-sé (both legs are about 130V above ground).

I've found a few testers which have a lead which can have the plug replaced but the one in the OP is the first I've seen specifically aimed at Thailand.

Using a voltstick / neon screwdriver alone can give misleading results, for example it may light on a disconnected ground (by capacitive coupling).

With most of the world (and so most imported electrical items) using live on the right side then it may not be such a problem that the live and neutral may have been transposed at the outlets ? The majority of items have 2 pin plugs fitted which can often be inserted either way around and hopefully have a double pole on/off switch. For earthed appliances sold in Thailand they are often sold fitted with a European plug, where the polarity would follow European conventions. If the socket outlet has been wired correctly for Thailand (live on the left) it would then become necessary to rewire the 3 pin European plug. Any idea why Thailand decided to be different and have live on the left side ?

EDIT : Assuming that the European 3-pin plugs fit Thai outlets ?

[emanphoto]

So what you're saying is this is one instance where "crossed wires" should be OK?

With most of the world (and so most imported electrical items) using live on the right side then it may not be such a problem that the live and neutral may have been transposed at the outlets ? The majority of items have 2 pin plugs fitted which can often be inserted either way around and hopefully have a double pole on/off switch. For earthed appliances sold in Thailand they are often sold fitted with a European plug, where the polarity would follow European conventions. If the socket outlet has been wired correctly for Thailand (live on the left) it would then become necessary to rewire the 3 pin European plug. Any idea why Thailand decided to be different and have live on the left side ?

[thomasteve]

So what you're saying is this is one instance where "crossed wires" should be OK?

With most of the world (and so most imported electrical items) using live on the right side then it may not be such a problem that the live and neutral may have been transposed at the outlets ? The majority of items have 2 pin plugs fitted which can often be inserted either way around and hopefully have a double pole on/off switch. For earthed appliances sold in Thailand they are often sold fitted with a European plug, where the polarity would follow European conventions. If the socket outlet has been wired correctly for Thailand (live on the left) it would then become necessary to rewire the 3 pin European plug. Any idea why Thailand decided to be different and have live on the left side ?

Well I would not condone doing the wiring incorrectly but it may not be as unsafe as it first seems.

Most appliances have 2 -pin plugs which can be inserted either way.

If the European (eg.Schuko) 3 -pin plugs do not fit your Thai socket outlets (due to the pin spacing) then it becomes necessary to replace them anyway so you can rewire according to the correct Thai configuration.

Many of the Thai multistrip and extension sockets have the L and N wired wrongly so beware if you need to use them.

[Crossy]

L & N transposed at the outlet isn't going to be immediately fatal or even present a significant hazard (unlike in the UK where our fused plugs could result in live equipment with an open fuse).

That said it isn't right, and we are in the business of doing things right (or at least as right as possible here).

However, an L - N swap at the incoming supply does present an immediate hazard, so it's important to:-

1. Know you have a swap
2. Know where the swap occurs

[thomasteve]

I would also first check that the tester unit itself has been wired up correctly to its attached plug - with the live pin on the left (do you have a photo of the 3 -pin plug or is moulded onto the back of the tester unit ?

It looks as if it has been modified for Thailand.

L & N transposed at the outlet isn't going to be immediately fatal or even present a significant hazard (unlike in the UK where our fused plugs could result in live equipment with an open fuse).

That said it isn't right, and we are in the business of doing things right (or at least as right as possible here).

However, an L - N swap at the incoming supply does present an immediate hazard, so it's important to:-

1. Know you have a swap
2. Know where the swap occurs

[wayned]

"I've found a few testers which have a lead which can have the plug replaced but the one in the OP is the first I've seen specifically aimed at Thailand."

An adapter can easily be made. Three pin plugs and sockets are available at most electric supply shops. Wire a short adapter with the L & N reversed. Am I missing something?

[Crossy]

"I've found a few testers which have a lead which can have the plug replaced but the one in the OP is the first I've seen specifically aimed at Thailand."

An adapter can easily be made. Three pin plugs and sockets are available at most electric supply shops. Wire a short adapter with the L & N reversed. Am I missing something?

Nope you're missing nothing, but the whole point of these simple testers is so that 'Average Joe' has a foolproof check of his outlets. Making up correctly wired adaptors isn't in his remit.

I've seen one of these MeaTech testers, nicely made and look the business. Cost 200 Baht apparently from 'the MEA shop on Petchaburi' if that's of any help (2nd hand info on the place it came from). From the brand name I suspect they were specially commissioned by MEA.

EDIT I was right, MEA website for the tester http://www.mea.or.th/minisite/home.php?site=meatech

[stephanienyc]

OK, you Europeans are thinking way too much about this. Let's look at a Thai outlet and think like an American (which is what these outlets are basically). It is quite easy to determine how it should be wired.

Ignore the round openings on the sides of the vertical slots, for now - our concern is the vertical slots themselves.

Looking closely at the face, you will see one vertical slot that's slightly bigger than the other.

The "wider" slot is supposed to always be the NEUTRAL (or white wire). Sometimes this terminal is silver-colored or has a W - for 'white' or an N (for Neutral) marked on it.

If we take our multimeter (the tech's best friend) and put it across the wide slot and the earth hole, thould be ZERO volts between this wide slot and the ground or earth connection (the round, or U-shaped hole).

The narrower slot is the LIVE. On some outlets I've seen this terminal colored brass. Using your multimeter, you should about 220 volts (or 110/120 here in USA) between either the earth (round hole) or the wider Neutral slot.

If you don't have voltage to earth from either terminal then you have an Open Ground.

Now, as far as the orientation of the Earth terminal, this doesn't matter. The US Electric Code does not specify which direction it goes.

Usually it's the electrician's preference or local convention -- for instance here in my area North Carolina, we install usually outlets with the earth terminal up. In New York City, outlets are usually mounted horizontally or with the ground opening pointing down.

Use what works best for you.

See how easy that was?

Hope that helps somewhat.

[TheMysteriousMrTesla]

Sorry Stephanie, but your biased, US-Centric, patronising posts are about as welcome as a fart in a spacesuit (and as helpful).

EDIT. Would 'no voltage between either pin and ground' not also indicate no live? Or am I missing something?

[Crossy]

@Stephanienyc

Whilst Mr Tesla's comment may be a little over the top I'm not sure how using one of the 3-light testers could be considered 'thinking way too much', after all it's significantly easier and safer than poking around a live outlet with a multimeter.

It's important to realise that these testers have literally just become available in Thailand which is excellent news for everyone with even a passing interest in electrical safety.

By the way, I've examined half a dozen different outlets that I have 'in stock', none have coloured terminals, none have markings other than L, N and E (or the Ground symbol), the better quality ones do have the wide neutral slot.

[bankruatsteve]

Sorry Stephanie, but your biased, US-Centric, patronising posts are about as welcome as a fart in a spacesuit (and as helpful).

EDIT. Would 'no voltage between either pin and ground' not also indicate no live? Or am I missing something?

No voltage between ground and either other pin would mean: 1) open ground or 2) No live or 3) Both

[stephanienyc]

@Stephanienyc

Whilst Mr Tesla's comment may be a little over the top I'm not sure how using one of the 3-light testers could be considered 'thinking way too much', after all it's significantly easier and safer than poking around a live outlet with a multimeter.

It's important to realise that these testers have literally just become available in Thailand which is excellent news for everyone with even a passing interest in electrical safety.

By the way, I've examined half a dozen different outlets that I have 'in stock', none have coloured terminals, none have markings other than L, N and E (or the Ground symbol), the better quality ones do have the wide neutral slot.

Wasn't talking about the testers. Just the ensuing conversation about them. While I agree those testers are handy (and I own a couple), before use, I would first verify the wiring of one of these things on a known good socket that has been checked first with a multimeter.

As far as US-centric, we're talking about a system that uses American-style outlets (albeit slightly modified) as its user interface. You gotta think US.

If it were a British ring system with the big chunky plugs and their peculiarities, you'd have to think in a UK-centric way. I mean, who else has a fuse inside their plug as a requirement! (at the end of the day, it's the best system, I believe, though)

As far as markings, it all depends. The ones with the "colored" terminals (one screw just being chrome plated, basically) usually have standard terminal screws you wrap the wires around. The ones that you have probably use grub-screw type lugs, I would imagine the L,N and E markings are all they come with.

To add to the soup, the versions for 110 (American style) and 220 (Schuko) sold in South Korea, use pressure-lock (wire-stab) terminals with quick-release for Live and Neutral. They just have engraved L and N markings on the plastic housing. The earth terminal, oddly enough, is a conventional screw that has been colored green. Go figure.

[Crossy]

Actually, we have to think Thailand, that's where we are.

This PEA document is worth a look (it's in Thai but plenty of pictures) http://www.crossy.co.uk/Handy%20Files/groundwire.pdf

You will indeed notice many similarities to the way the NEC does things.

[emanphoto]

Here is the requested shot of the outlets.

[Crossy]

Ah the dreaded 'universal' outlets.

If I were you I'd get rid and replace with pukka Thai outlets unless you regularly use kit that has UK or Aus plugs.

The issues;

1. Many of these don't have shutters
2. Do you wire live left or right? Thailand leads the world with 220V live on the left, everywhere else is live on the right.
3. The contact area can be very small, don't trust with loads over a few hundred Watts.
4. Once a UK plug has been used the contacts can be permanently deformed, poor contact with other types.

EDIT Those don't look like standard Thai size backplates, could be brewing issues when you need to replace the outlets.

EDIT 2 Since this is a new install does the distribution board have an RCD/RCBO (it will have a 'Test' button)? No? Reject as not to local code!

[stephanienyc]

Agreed. My experience is that the universal outlets are best suited to UK type and roun-pin plugs. Not so much the flat pin types like Aussie and American - contact seems to be very gamey - I've had to jiggle American-type plugs a little sometimes to get them to make contact. Not something I'd trust to plug a vacuum cleaner or other heavy-current appliance at ALL!!!

And yeah, in the position they are innstalled with earth-up, the should be wired with live to the left - since if you plug a device with an American-type three-pin plug (invariably polarized), it should mesh with the neutral on right, live on left and earth up; provided the plug has been correctly wired.

The problem then is that UK plugs and (I believe) Aussie plugs will be reverse-polarized in relation to the American earthed types. It's basically our fault - our plugs are backwards in relation to those from two other major standard countries, so we end up throwing everyone off.