Quietly Adding A Ground Wire To A Single Socket

[dmullerd]

I'm a new teacher in Chiang Mai and part of my contract includes an apartment on campus. All the wall outlets (receptacles) are the two pronged variety and a quick inspection of the surface mounted wiring leads me to believe the there is no separate ground in the system.

The problem I have is that my audio equipment makes a buzzing sound and my computer (MacBook Pro) has a current running throw the case. My arms tingle when I type. Apparently, I'm not alone with the MacBook problem but grounding the outlet may help.

A study of this forum leads me to believe that a the neutral wire may also serve as a ground in Thai electrical systems and that an adapter that combines the third prong and neutral prongs on my plug will solve the problem.

IS THIS SO?

If not can I buy a copper ground bar drive it into the ground and run a wire from it to my wall outlet and install a three pronged receptacle?

[Crossy]

Start here:- http://www.crossy.co.uk/wiring/2pin.html

Grounding will certainly help with your tingle and your hum, you may also score by reversing the plug in the outlet. The tingle is caused by leakage through the mains filter in your PSU (it is not a fault), you don't need a particularly good ground to stop it although obviously, the better the ground, the better the solution.

Although you are correct in your assertion that Neutral and Ground are at the same potential and linked at the transformer the use of an adaptor to connect them could be lethal!! Should you insert the plug into the outlet the wrong way round (unlike the US the 2 pin outlets are not polarised) your adaptor will link Ground and Live resulting in something more than a tingle

EDIT Obviously this will only help if your PC has a 3 pin plug attached

Edited August 19, 2008 by Crossy

[dmullerd]

Any recommendations about where to get the adapter with the ground loop or a 1.5M ground spike in ChaingMai?

Thanks

[VocalNeal]

Any recommendations about where to get the adapter with the ground loop or a 1.5M ground spike in ChaingMai?

Thanks

Sorry I can't tell you where. BTInco is a large distributor but I can't find them in ChiangMai.

But they are common and will be available at ANY decent electrical supply store.

About 75 Baht including the clamp. You can't carry them on a motorbike or in a taxi!!!

If you have an electric drill you can "drill" them into the ground.

[dotcom]

Any large electrical supply store + Home Pro.

Excellent idea on the clamp.

Pound the rod into the ground with a hammer.

[dotcom]

Crossy. Allow me to add this to your collection.

This is a proper (USA) 3 to 2 plug adapter.

Just like you I am not suggesting anyone use it. Unless you know what you are doing.

You will clearly see that on the male side the 2 spades are different size. The thin one is meant to be live & the wide one is meant to be neutral. The problem (as you well know) is that most houses don't have the correct sockets.

Adapter

[dotcom]

Now that's all fine & dandy if you have the correct National Clipsal or equivilent sockets.

If you have this socket & it's wired up correctly - live to the narrow one & neutral to the wide one all will be well.

[lopburi3]

Crossy. Allow me to add this to your collection.

This is a proper (USA) 3 to 2 plug adapter.

Just like you I am not suggesting anyone use it. Unless you know what you are doing.

You will clearly see that on the male side the 2 spades are different size. The thin one is meant to be live & the wide one is meant to be neutral. The problem (as you well know) is that most houses don't have the correct sockets.

Adapter

But that adapter is only designed for grounded outlets in the US where the holding screw for front plate is at ground potential and is used to secure the adapter to the outlet. I have never seen such an outlet in Thailand.

[Crossy]

But that adapter is only designed for grounded outlets in the US where the holding screw for front plate is at ground potential and is used to secure the adapter to the outlet. I have never seen such an outlet in Thailand.

All the adaptors of this style that I have look like that complete with asymetric pins.

It had never occured to me that the intended use was as Lop describes (I've never seen a genuine US 2 pin outlet) but it does make sense. I always assumed that the tab was for a ground wire to be attached

[Tywais]

I always assumed that the tab was for a ground wire to be attached

Lop is correct in that it normally connects to the socket plate screw where the steel housing is usually grounded (US). However, as I posted once before, it works very well as a ground screw point as shown below. I installed it in my home computer room/office and plugged in a "real" 3 wire power strip.

[longball53098]

I always assumed that the tab was for a ground wire to be attached

Lop is correct in that it normally connects to the socket plate screw where the steel housing is usually grounded (US). However, as I posted once before, it works very well as a ground screw point as shown below. I installed it in my home computer room/office and plugged in a "real" 3 wire power strip.

That seems to work but why not take it one step more and change the socket to a 3 pin socket, connect your green earth wire to the actual socket earth pin and bring it out under the plastic coverplate, get rid of that adapter and you have a good earthed socket at that point.

[dotcom]

But that adapter is only designed for grounded outlets in the US where the holding screw for front plate is at ground potential and is used to secure the adapter to the outlet. I have never seen such an outlet in Thailand.

But they are available.

Hi fi stores in Fortune town & E square mall sell Eagle Electric sockets & cover plates. Just as Tywais has shown. So does my specialist elec supply store on Sukhumvit Road at the traffic light at Soi 62. I also know a place on Suk 71 PD that keeps them.

Crossy. The USA cover plates attach via one single screw dead center of the cover. Yes you would undo this & run the screw through the 3 to 2 adapter & hence the cover plate.

But that assumes the you are using a metal wall box & that is earthed.

I'll get some pictures. My Hi-Fi is wired up this way.

Hi-Fi male plug.

Edited August 28, 2008 by dotcom

[lopburi3]

We are talking about ungrounded outlets. Buying an American metal outlet box is not going to change anything - it is still ungrounded unless you run new ground wire - and if you are going to do that you can replace with normal outlet box/grounded outlet used here and then there is no need for the three pin to two pin adapter.

[petercsea]

We are talking about ungrounded outlets. Buying an American metal outlet box is not going to change anything - it is still ungrounded unless you run new ground wire - and if you are going to do that you can replace with normal outlet box/grounded outlet used here and then there is no need for the three pin to two pin adapter.

Agree with this Lop. The adaptor is a short-term fix waiting for tomorrow's solution. The adaptors aren't so stable and the quality control is low. Came across two units where inserting the plug pushed the earth tab back through the moulding.

I use one for plugging a three pin earthed solenoid into to a timer plug-in module. I tried many places to locate a three hole type timer but no luck. Should I be considering a different solution or has anyone seen one here? Really don't like the adaptor when I already have an earthed power point

[technocracy]

In terms of adding a ground 'quietly' why not buy an earth equipped extension lead - replace the 3 pin socket with a 2 pin socket then disconnect the earth lead inside and replace with a trailing length of cable which you can connect to the ground rod.

Not only will it give you an earth without touching the original sockets, you also get 3 or 4 ground sockets instead of one and it relatively portable.

Jobs a good'un!

[lopburi3]

I suspect you are talking about replacement of the plug (male) rather than socket (outlet) (female). Actually if you check closely you will find most extension cords with that appear to be grounded sold at Tesco are not grounded and have two pin plugs installed. Be careful.

[technocracy]

I suspect you are talking about replacement of the plug (male) rather than socket (outlet) (female). Actually if you check closely you will find most extension cords with that appear to be grounded sold at Tesco are not grounded and have two pin plugs installed. Be careful.

Yes I am and the for the reason you state about extension not having a ground is why I specified an 'earth equipped extension'.

[dotcom]

You mean like this?

Grounded extension "power strip" with reset breaker.

Yeah spend a few pennies more & sleep better. A must for computer systems. Brand: Toshino.

[dotcom]

If not can I buy a copper ground bar drive it into the ground and run a wire from it to my wall outlet and install a three pronged receptacle?

This is by far your best solution.

The problem a lot of people face is living on a higher floor it's impractical to run their own grounds. In the old days you could just use water pipes. Today that is no longer an option.

If you are able to then this beats the band-aid solution every time.

[dotcom]

Here ya go Crossy. Another one for your collection. USA grounded female socket, grounded & polarity (phase). You can see the way the cover attaches, that screw would go through the orange adapter. Though I can't envision any reason why a person would want to.

These are widely available & fit a standard wall box.

[lopburi3]

Prior to that outlet they were two pin only but the center screw was grounded as it attaches directly to the metal outlet frame and that in turn attaches to the metal outlet box and the box connects to the metal conduit which leads to ground. The next step (1950's I believe) was to install a ground wire to the outlet box (due to the often suspect connections of the conduit connections/corrosion.

[IraqRon]

Prior to that outlet they were two pin only but the center screw was grounded as it attaches directly to the metal outlet frame and that in turn attaches to the metal outlet box and the box connects to the metal conduit which leads to ground. The next step (1950's I believe) was to install a ground wire to the outlet box (due to the often suspect connections of the conduit connections/corrosion.

I had similar situation. Bought grounded outlets to change out and ran the ground thru the wall to grounding rod I put just outside. Bought good quality grounded power strip to plug in and now feel better about the thing. However, how do you determine neutral in a 240 system?

[Tywais]

However, how do you determine neutral in a 240 system?[/size]

Two ways one can do it. If you have an AC Voltmeter, connect one lead to earth ground and the other to one of the pins then the other. The pin that doesn't read 220 is the Neutral. 2nd way is with one of those screwdrivers with a neon bulb in it. Whichever outlet pin doesn't light the bulb is Neutral.

[sleepyjohn]

Hi

I've got to make a grounded supply for a UPS.

I will make my own ground with a copper rod.

My question is, as I have to get the polarity correct when I put a socket together, which of the pins on a Thai 3pin plug is the live? Better still, as these plugs are usually heat sealed, which colour wire from teh plug should be L or N or E?

ps: how long for the copper rod....I've seen some very short ones (as the actress said to the bishop).

thanks

[Crossy]

My question is, as I have to get the polarity correct when I put a socket together, which of the pins on a Thai 3pin plug is the live? Better still, as these plugs are usually heat sealed, which colour wire from teh plug should be L or N or E?

ps: how long for the copper rod....I've seen some very short ones (as the actress said to the bishop).

Looking into the outlet with the ground at the top Live is on the left

Your cord should follow one of the standards:-

black-live, white/grey-neutral, green-earth

or

brown-live, blue-neutral, green & yellow-earth

or (rare)

red-live, black-neutral, green-earth.

If you're only grounding one outlet, and you have an ELCB (GFI, RCD, Saf-T-Cut) then a 1m rod should be adequate provided your ground is not too dry.

Useful information here:- http://www.crossy.co.uk/wiring/2pin.html

Edited November 10, 2008 by Crossy

[dingdongrb]

You can't carry them on a motorbike or in a taxi!!!

Why is that?

As far as the screw holding the faceplate of a USA made electrical outlet box being grounded, this is not always true even in the USA these days. As everyone is trying to make things easier and using plastic junction boxes instead of metal these days that faceplate screw is probably not at ground potential. Also in USA home construction it is very very rare to use conduit to run electrical wires through. This is typically only done in commercial construction and then again not always the case due to the $$$$$$.

[kenk3z]

I believe the current typical USA-style house wiring uses three-conductor "romex" which is just a (relatively) heavy plastic insulation. You have two current carrying wires plus a ground wire. The socket box on the wall will be plastic, but the socket assembly itself has a means of accepting the ground wire - either a push in catch system or a screw. Since the socket is the current three-conductor style, the adapter shown higher up that uses the center screw for grounding is not required.

The adapters were for use in older houses that were wired with two conductor sockets. The presumption is that the box is metal and had a screw to hold the ground wire. However, you go back far enough in time then the house wiring is two conductor wire and not three - so the box is not grounded in such a case.

So the suggestion I would make for wiring in Thailand is to not trust that those two-to-three "grounded" adapters actually provide a ground.

kenk3z

[Crossy]

So the suggestion I would make for wiring in Thailand is to not trust that those two-to-three "grounded" adapters actually provide a ground.

Correct. What we recommend is to use the adaptor but to run a ground wire from the tab to a 'decent' ground