Thai Electrics

[sinbin]

I've been having problems with my electrics for years. I've lost count of electricians ( I use that word loosely) who have looked at the problem. None succeeding in finding a solution, but may be the last one did ? We wait and see.

Anyway, the wife always complained about getting a shock when doing the washing (laundry). I changed the earthing rod, fitted a new cable and still no change. Even had recommendation to have a complete house rewire.So eventually I bought a multimeter and investigated myself. I found that my neutral cable into the house was live and continually carried 2-4 volts. So we got the electric company to send someone out. The guy found that someone had connected my neutral wires to earth in my consumer unit. He disconnected that and fitted an then earth cable from my outside meter box into the ground. Still the problem remained that the negative line to my house carries voltage. The electrician said even though it does, my wife shouldn't receive a shock. On asking him why the negative carries a small voltage he just said 'the cables used in Thailand are of poor quality'.

So my question is, is he right that my wife won't get any more shocks ? Has anyone else checked their neutral and found the same problem ?

[Crossy]

A Neutral - Earth voltage of a few volts is normal and is nothing to worry about, 2-4 Volts will not cause a shock.

A Neutral to Earth link (MEN or PME connection) is also normal in many areas, most new installations are required to be wired in this way. Removing this link if it is intended to be fitted could cause a hazard (as could fitting one if not intended).

Is your washing machine correctly connected to the earth? (3 pin plug in the correct outlet). Are shocks received from the metalwork, or from the water itself?

Have you verified that the earth pin of the outlet is actually connected to your earth rod?

If you have a neon-screwdriver does it light when you touch the metalwork of the washer?

Do you have an RCD (ELCB, Safe-T-Cut, GFI) installed? If not install one now, whilst it won't stop the tingles it will make your installation much safer.

[InterestedObserver]

The short version is that your system is not properly grounded and/or connected. There should be no voltage (shock) on the metal frame of any appliance. The metal frame of major appliances should be connected to ground, either directly or via the 3-prong plug. Voltage on the neutral is a secondary concern, neutral is not normally connected to the frame. There are exceptions to the above, buy you should not get a shock from electrical appliances.

[sinbin]

A Neutral - Earth voltage of a few volts is normal and is nothing to worry about, 2-4 Volts will not cause a shock.

That's reassuring, but it did before the Elec' Board electrician turned up.

A Neutral to Earth link (MEN or PME connection) is also normal in many areas, most new installations are required to be wired in this way. Removing this link if it is intended to be fitted could cause a hazard (as could fitting one if not intended).

Obviously with Elec' Board man removing it then it wasn't requires !!

Is your washing machine correctly connected to the earth? (3 pin plug in the correct outlet). Are shocks received from the metalwork, or from the water itself?

Yes my machine is correctly connected to earth. Wife says shock from water, not appliance.

Have you verified that the earth pin of the outlet is actually connected to your earth rod?

According to the Elec' Board man, everything seems in order.

If you have a neon-screwdriver does it light when you touch the metalwork of the washer?

No it doesn't. Also checked it with a Multimeter, no voltage.

Do you have an RCD (ELCB, Safe-T-Cut, GFI) installed? If not install one now, whilst it won't stop the tingles it will make your installation much safer.

Yes, have RCBO on my consumer unit and ELCB's on the showers. Neither trip when receiving shock

Thank you for your reply Crossy. If Neutral does carry 2-4 volts, and that is normal, then my question has really been answered. The difficult bit now is to see if the missus will try and put herself in a position to deliberately get a shock to see if the Elec' Board man is correct in his remedy.

PS. To confirm Neutral wires do indeed carry voltage I checked my mother-in-laws house and she also has.

Edited November 26, 2011 by sinbin

[sinbin]

The short version is that your system is not properly grounded and/or connected. There should be no voltage (shock) on the metal frame of any appliance. The metal frame of major appliances should be connected to ground, either directly or via the 3-prong plug. Voltage on the neutral is a secondary concern, neutral is not normally connected to the frame. There are exceptions to the above, buy you should not get a shock from electrical appliances.

If a shower is an electrical appliance then we did get a shock off of those even though they are fitted with ELCB's. Anyway, at present, since the Elec' Board man attended, I've had showers and I haven't been shocked as before. As said before, the removal of the Neutral wire that bridged onto my earth may have finally solved my problems. Thanks for your input. Edited November 26, 2011 by sinbin

[Spoonman]

The difficult bit now is to see if the missus will try and put herself in a position to deliberately get a shock to see if the Elec' Board man is correct in his remedy.

Stand beside her and get ready to give her a good solid kick if the water bites and she cannot let go.

[electau]

With the TT system of earthing a voltage to earth is normal 2 to 4 volts.

The installation was connected as a MEN system, there is nothing wrong with this as long as it is compliant with PEA/MEA requirements.

You should check the earthing you will most probably have not compliant earthing system and the earthing system will remove any small voltages that may appear due to leakage.

You should also check to see if you have 30mA RCD protection on all final sub circuits.

The main earth electrode should be 13mm copper clad steel 1.2/1.8metres into the soil.

You seem to have poor earthing or no earthing.

[sinbin]

Electau I have replaced the Earth rod and cable, they are fine. Anyway, things are fine at the moment as the wife isn't complaining anymore. All the Elec' board guy did was remove the cable connecting Neutral to Earth in my consumer unit, and put an Earth cable from my outside meter box into the soil.

Just to clarify as to how all this started is/was due to a power surge. It took out my RCBO and a couple of house appliances, inc my computer. Since then I've fitted a whole house power surge protector. I recommend one, to everyone that doesn't have one.

Thank you for your input Electau.

[haveaniceday]

Just to clarify as to how all this started is/was due to a power surge. It took out my RCBO and a couple of house appliances, inc my computer. Since then I've fitted a whole house power surge protector. I recommend one, to everyone that doesn't have one.

Can anyone give any insight about one of these?

Where to get?

What it looks like?

Where in the circuit is it installed?

Can the avg Thai calling them selves an electrical guru install it?

Is it easy for me to install. (I highly doubt this, I try not to touch any thing street side of the RCCB)

Thanks.

[sinbin]

Just to clarify as to how all this started is/was due to a power surge. It took out my RCBO and a couple of house appliances, inc my computer. Since then I've fitted a whole house power surge protector. I recommend one, to everyone that doesn't have one.

Can anyone give any insight about one of these?

Where to get?

What it looks like?

Where in the circuit is it installed?

Can the avg Thai calling them selves an electrical guru install it?

Is it easy for me to install. (I highly doubt this, I try not to touch any thing street side of the RCCB)

Thanks.

My consumer unit is manufactured by Square D, so I bought their power surge protector. Cost 2,200-2,500 Baht, including a separate housing box. The model I fitted was a QO-SPD225. It is very easy to fit as it comes with 2 wires only. Before you buy, you can familiarise yourself with fitting one by googling. Get or order at any house electric suppliers. It's fitted right next to your consumer unit and has a neon light to indicate it's working.

http://www.un-electric.com/index.php?product_id=98&page=shop.product_details&category_id=7&flypage=flypage.tpl&option=com_virtuemart&Itemid=2

[PattayaParent]

The difficult bit now is to see if the missus will try and put herself in a position to deliberately get a shock to see if the Elec' Board man is correct in his remedy.

Stand beside her and get ready to give her a good solid kick if the water bites and she cannot let go.

WARNING - BEFORE you attempt this make sure that the insurance premiums are fully paid up and even top up the beneficiary amount if you can.

[haveaniceday]

Thanks sinbin in post #10.

ON a separate note, I remember years ago, being told by a guy in a computer shop, who as far as I know is totally un qualified to advise, that I should not use two surge protectors on my computer, eg, in the UPS and a little Belkan one on a board after the UPS.

Can anyone see any issues have a whole house surge protector and then having many small 1000w UPS spread around on electrics like computers ?

Presuming they are properly grounded etc.

[Crossy]

Absolutely zero problem ^^^. I can't imagine why someone would say that you can't use multiple surge arrestors, the more the merrier

I wonder if he actually meant that you don't NEED extra ones if you're using the UPS's built in arrestor?

As to having lots of small UPSs, no problem there either. My preference is for a whole house UPS (and genset) as it probably works out slightly cheaper for an equivalent run time but of course one UPS failure and the lot goes off

[Thighlander]

I had a little bit of a spark, when I plugged in my 230v a/c system. I re-twisted the wires at the junction box, and it went away.

[Crossy]

I had a little bit of a spark, when I plugged in my 230v a/c system. I re-twisted the wires at the junction box, and it went away.

I really hope you are winding us up here. Why would anyone go to the trouble of re-making a connection without actually doing it properly.

[Thighlander]

retwisted and capped....nothing wrong with that. simple solution to a complicated problem.

[Crossy]

retwisted and capped....nothing wrong with that. simple solution to a complicated problem.

Assuming you used a new wire nut and installed it correctly OK I'll go with that. Personally I don't like the things particularly on high current circuits and there's a reason they are not permitted in UK wiring.

By the way, the correct way to use a wire nut (according to the manufacturers) is that you DON'T twist the wires first (counter-intuitive I know), just poke the stripped ends into the correct size nut and wind it clockwise until tight.

[haveaniceday]

Reagarding the post above, what do you recommend using?

I see in a post, somewhere and I can not find it, you make mention of a ceramic joiner for high current, if my memory serves me right, (debatable I know !!!) some one on here made a comment that the plastic screw joiners are prone to melting under high current loads.?

Any comments?

[Crossy]

Avoiding joints is always the best way to go

Personally, on anything up to 6mm² I would use Wago connectors (see my thread on finding the beasts).

Or, use barrel crimps applied with a proper ratchet crimping tool and finished off with heatshrink, these are classed as maintenance-free by UK regs although putting them half way down a conduit run is frowned upon.

If you don't want to go there then the plastic choc-blocks are pretty good provided you get one big enough for the current rating of the circuit not just one that the wires will fit, I have some 5A blocks that will happily take a 2.5mm² cable. Back home they are actually marked with a rating, none of the ones I have in my box are As a rule of thumb (not infallible) if you can get two wires the size you are using into each end of the block then it should be adequate.

One personal foible I have when using these things to join two wires is to strip both wires long enough that the core goes under both screws (make sure it doesn't poke out the other end). The idea being to ensure the largest possible contact area between the wires and the connector, minimising the contact resistance and therefore the local heating effect.

No idea if it actually makes a significant difference, but the only one I've had melt was because it was hidden behind an oven and melted as a result of the oven heat rather than overload, a classic application for one of the ceramic ones.