Help Please!

[thaibeachlovers]

As some on here know, I have been rewiring the MIL house. Everything works properly, BUT I wanted to test a new plug, so I used the only item of test equipment I have available ( I know I should have a multimeter, but it's a long story ), one of those small screwdrivers with a bulb in the handle, stuck it in the L hole and nothing. put it in the N hole and it lit.

Now, perhaps that is what is supposed to happen, but I would have thought that it would light in the L hole. Thought that that plug might have been wired wrong, but every plug in the house is the same.

Therefore, it is either supposed to light in N or the person that connected the wire to the outside line did so the wrong way around. I wired as advised in this forum, black is L ( hot ) and grey is N ( neutral ) .

I did try google, but only got advice for using meters, which doesn't help me.

Any help on this will be gratefully received. It will be no problem to reverse the mains wire if that will rectify the situation, but I'm not going to do that without checking first.

Thanks for any help.

[surayu]

Probably those wires for that particular power's point have been connected the other way round.

So, if i was in you, i would chase that particular wire to see where is the problem

[Artisi]

You need to establish which in L and which is N coming into the house / switch board - as well as checking that the power circiut is correctly connected at the board - it is possible the error is there.

Edited August 12, 2011 by Artisi

[thaibeachlovers]

Probably those wires for that particular power's point have been connected the other way round.

So, if i was in you, i would chase that particular wire to see where is the problem

No, every plug in the house is the same.

[InterestedObserver]

Unless it is a polarized plug/receptacle it does not matter. Line (L) should indeed light the neon bulb in the screwdriver. Neutral (N) normally should not light the neon bulb since it is referenced to ground/earth at some point.

Edited August 12, 2011 by InterestedObserver

[thaibeachlovers]

You need to establish which in L and which is N coming into the house / switch board - as well as checking that the power circiut is correctly connected at the board - it is possible the error is there.

I agree, but how do I establish that? Do I have to go and buy a multimeter, or does the screwdriver test prove that the wires from outside are reversed?

Thanks guys.

[Artisi]

You need to establish which in L and which is N coming into the house / switch board - as well as checking that the power circiut is correctly connected at the board - it is possible the error is there.

I agree, but how do I establish that? Do I have to go and buy a multimeter, or does the screwdriver test prove that the wires from outside are reversed?

Thanks guys.

Get the local power authority to come and check for you because the other problem you might have is that the active (L) is not being isolated (dangerous if you only have a single pole switch) if and when you turn off the main switch at the switch board.

[thaibeachlovers]

Unless it is a polarized plug/receptacle it does not matter. Line (L) should indeed light the neon bulb in the screwdriver. Neutral (N) normally should not light the neon bulb since it is referenced to ground/earth at some point.

Thanks for that. Now I know that some past person has reversed the wire leading to the house.

However, I merely replaced the wiring and plugs/ switches ( and added an RCBO and earths ) as they were already, so at no point is the neutral connected to earth. Does that make a difference?

[thaibeachlovers]

You need to establish which in L and which is N coming into the house / switch board - as well as checking that the power circiut is correctly connected at the board - it is possible the error is there.

I agree, but how do I establish that? Do I have to go and buy a multimeter, or does the screwdriver test prove that the wires from outside are reversed?

Thanks guys.

Get the local power authority to come and check for you because the other problem you might have is that the active (L) is not being isolated (dangerous if you only have a single pole switch) if and when you turn off the main switch at the switch board.

Thanks, but at least that is not a problem, as I have installed an RCBO, which I believe is a combined main switch and RCD, plus there is definitely a double pole switch ( 30 amp ) between the RCBO and before the breaker box.

[surayu]

Thanks for that. Now I know that some past person has reversed the wire leading to the house.

That's just what i was trying to tell you, but in your reply you dismissed that possibility as if you had already checked the whole wire lenght......anyway, it's good to know you are fine now

[thaibeachlovers]

Thanks for that. Now I know that some past person has reversed the wire leading to the house.

That's just what i was trying to tell you, but in your reply you dismissed that possibility as if you had already checked the whole wire lenght......anyway, it's good to know you are fine now

Sorry if it came across that way, but I had just installed the wire, and double checked that it was connected correctly.

[InterestedObserver]

Unless it is a polarized plug/receptacle it does not matter. Line (L) should indeed light the neon bulb in the screwdriver. Neutral (N) normally should not light the neon bulb since it is referenced to ground/earth at some point.

Thanks for that. Now I know that some past person has reversed the wire leading to the house.

However, I merely replaced the wiring and plugs/ switches ( and added an RCBO and earths ) as they were already, so at no point is the neutral connected to earth. Does that make a difference?

The neutral (N) would be connected to earth at the supply transformer by PEA.

[thaibeachlovers]

Unless it is a polarized plug/receptacle it does not matter. Line (L) should indeed light the neon bulb in the screwdriver. Neutral (N) normally should not light the neon bulb since it is referenced to ground/earth at some point.

Thanks for that. Now I know that some past person has reversed the wire leading to the house.

However, I merely replaced the wiring and plugs/ switches ( and added an RCBO and earths ) as they were already, so at no point is the neutral connected to earth. Does that make a difference?

The neutral (N) would be connected to earth at the supply transformer by PEA.

Thanks for that information. I learned something new then.

So tomorrow I shall change the wires to the RCBO, unless someone tells me not to.

[InterestedObserver]

Unless it is a polarized plug/receptacle it does not matter. Line (L) should indeed light the neon bulb in the screwdriver. Neutral (N) normally should not light the neon bulb since it is referenced to ground/earth at some point.

Thanks for that. Now I know that some past person has reversed the wire leading to the house.

However, I merely replaced the wiring and plugs/ switches ( and added an RCBO and earths ) as they were already, so at no point is the neutral connected to earth. Does that make a difference?

The neutral (N) would be connected to earth at the supply transformer by PEA.

I should have added, unless it is an unearthed (IT) system.

[Crossy]

In your consumer unit check that the neon lights when one of the MCB buss connections (assuming they're all single pole).

If it does then your fault is elsewhere. If it does not light chances are that you have L & N reversed on the incomer.

[thaibeachlovers]

In your consumer unit check that the neon lights when one of the MCB buss connections (assuming they're all single pole).

If it does then your fault is elsewhere. If it does not light chances are that you have L & N reversed on the incomer.

Yes indeed, it was the incoming wires reversed. I realised in the night, that I had not checked the obvious thing, the incoming wires, and yes, lit on grey, nothing on black. So now the wires are reversed to the RCBO, I've written next to the wrong coloured wires what they in fact are, and the test light works in all the L holes.

Now, I'm getting my wife to check how much it is for the power people to come and install a knife breaker where the mains lines come to the house. It's a drag not being able to do a proper job.

AC is pretty amazing. Everything works just fine the wrong way around! Is there any problem in fact, other than for anyone playing with what they think is a neutral, and it is live?

Thanks everyone.

PS, great housbuilding thread, Crossy.

[Crossy]

The BIG issue with an L - N reversal on the incomer, is that all your breakers are in the neutral. This means that if you isolate a circuit using the breaker all the wires instead of being dead will make you dead, not a good situation.

[thaibeachlovers]

The BIG issue with an L - N reversal on the incomer, is that all your breakers are in the neutral. This means that if you isolate a circuit using the breaker all the wires instead of being dead will make you dead, not a good situation.

Yes, now that you put it that way!!!!!

Just as well then that I'm super cautious and always turn power off at the first available incoming switch, rather than the breaker, or I'd have been testing the RCBO for real ( assuming that that would work the wrong way around ). Guess it's not my time yet!

Thanks Crossy, great info as always.

[snarky66]

it is not clear to me if you have purchased & installed a breaker box yet. Any news? Any pictures?

My advice on the above. Remove the cover. Using tester screwdriver touch it to the N bus. If that's live your incoming wires are reversed. To fix that you can swap at the meter or at your load center. Makes no difference.

[maloyd1]

it is not clear to me if you have purchased & installed a breaker box yet. Any news? Any pictures?

My advice on the above. Remove the cover. Using tester screwdriver touch it to the N bus. If that's live your incoming wires are reversed. To fix that you can swap at the meter or at your load center. Makes no difference.

My advice is to start at the point where the supply enters the house and test to see if what should be the live is in fact live using your Screwdriver. I say this as you may have a sigle pole isolater switch that should be switching off the live and not the Neutral. Best to sort the issue from end to end.

Something in addition to this is the use of Thai extension sockets to convert Thai plugs to Multi way plugs (EU, USA, UK etc). I installed a new double socket with an earth as there was no earth present in my rented house and I wanted to earth down my PC stuff as I kept getting little shocks off the cases. As I had lots of equipment I needed two 6 way extension sockets. I made sure that on the first lead the live was in fact the correct way round. I then plugged in the secong lead (different make) and to my amazement the live and neutral were reversed. Traced the problem to the internal wiring of the second extension socket. Luckily I am an electronics technician so I had the gear to unsolder and revers the wires inside the socket. I know I could have chopped off the moulded Thai plug and replaced it but it was obvious looking at the wiring colour inside the socket that they had got them back to front. Also the internal current trip was on the neutrl line. My point is if you use Thai extension sockets or leads do check to see if the LIVE & NEUTRAL are the correct way round. Having them the wrong way round will not normaly stop any equipment working as it is A.C. current but it is good to know if the fuse blows in the plug (UK equipment) then it is the live that has been cut and not the neutral.

[electau]

AS Crossy states, you most probably have what is known as reversed polarity, the L and N supply cables have been reversed. It could be at the switchboard, the meter or at the connection at the connection of the service. You will have to get the PEA to check.

You should regard this as a potentially hazardous situation. All switching must be in the line (active) conductor.

It was caused by not carrying out a polarity test on connection to supply.

[Crossy]

Whilst we are on the subject a word of warning about neon screwdrivers.

Once upon a time every electrician had one of these in his toolbox, they are now frowned upon as a means of checking if a circuit is live. You can get what is generically called a VoltStick (it's actually a brand name http://www.voltstick.co.uk/ ), a battery powered device that does the same job but without actually having to make contact with the circuit being checked.

The problem with neon screwdrivers is that you form part of the circuit that causes the lamp to light. The current that flows is tiny (1mA or so) and non-lethal but I find I can feel it when I use mine with bare feet even on our wooden floor. There is a story of a young apprentice (no, it wasn't me) who dropped one in a bucket of water, not wanting to get in trouble he simply replaced it in the tool box with predictable results when his boss used it again.

I still think they are a useful tool in many ways better (and easier) than a meter, but care is required in their use, gingerly tap the metal cap the first time you use it just to be sure, check it's not damaged, and, of course, don't drop it in water.

One last warning, just because the lamp does not light does not mean the circuit is safe to touch (same goes for a Voltstick, the battery may be dead), if in doubt open the incoming (double pole) breaker and put a sign on it not to turn on.

[electau]

In reply to post #20.

It does not matter if the socket outlet has the line and neutral reversed as long as the switching is in the line (active conductor). As TIS standard sockets are unswitched unplugging the socket will break the line conductor.

Most socket outlets are marked L, N and E.

If you use 13A BS fused plugs with a TIS adapator the polarity should be changed in the 13A BS plug top not at the socket. As this may not be practicable due to their design you should replace the BS type with a compliant 3 pin TIS one.

[thaibeachlovers]

it is not clear to me if you have purchased & installed a breaker box yet. Any news? Any pictures?

My advice on the above. Remove the cover. Using tester screwdriver touch it to the N bus. If that's live your incoming wires are reversed. To fix that you can swap at the meter or at your load center. Makes no difference.

Yes, RCBO ( Safe T Cut ) installed, and wires now the correct way around to the in connections, though still wrong colour on the incoming 4mm cable, as some clever person by passed the knife breaker switch and attached the incoming cable ( wrong way around ) directly to the outside pole to house cables! Currently looking to get the power men to come and reroute the power to a new knife breaker switch.

Hope to have pictures at some time in the future.

[thaibeachlovers]

it is not clear to me if you have purchased & installed a breaker box yet. Any news? Any pictures?

My advice on the above. Remove the cover. Using tester screwdriver touch it to the N bus. If that's live your incoming wires are reversed. To fix that you can swap at the meter or at your load center. Makes no difference.

My advice is to start at the point where the supply enters the house and test to see if what should be the live is in fact live using your Screwdriver. I say this as you may have a sigle pole isolater switch that should be switching off the live and not the Neutral. Best to sort the issue from end to end.

Something in addition to this is the use of Thai extension sockets to convert Thai plugs to Multi way plugs (EU, USA, UK etc). I installed a new double socket with an earth as there was no earth present in my rented house and I wanted to earth down my PC stuff as I kept getting little shocks off the cases. As I had lots of equipment I needed two 6 way extension sockets. I made sure that on the first lead the live was in fact the correct way round. I then plugged in the secong lead (different make) and to my amazement the live and neutral were reversed. Traced the problem to the internal wiring of the second extension socket. Luckily I am an electronics technician so I had the gear to unsolder and revers the wires inside the socket. I know I could have chopped off the moulded Thai plug and replaced it but it was obvious looking at the wiring colour inside the socket that they had got them back to front. Also the internal current trip was on the neutrl line. My point is if you use Thai extension sockets or leads do check to see if the LIVE & NEUTRAL are the correct way round. Having them the wrong way round will not normaly stop any equipment working as it is A.C. current but it is good to know if the fuse blows in the plug (UK equipment) then it is the live that has been cut and not the neutral.

Everything is "interesting" in LOS.

I purchased an extension lead and multi plug box from Home Pro, but the 3 pin plug would not fit in the 2 pin sockets in my rented room. I therefore cut off the plug to put a 2 pin one on, but to my surprise the earth wire was RED. I had to open the casing to check, but yes, it was wired up with a red earth wire. Does China use red to earth? That's possibly where it was made.

[thaibeachlovers]

Whilst we are on the subject a word of warning about neon screwdrivers.

Once upon a time every electrician had one of these in his toolbox, they are now frowned upon as a means of checking if a circuit is live. You can get what is generically called a VoltStick (it's actually a brand name http://www.voltstick.co.uk/ ), a battery powered device that does the same job but without actually having to make contact with the circuit being checked.

The problem with neon screwdrivers is that you form part of the circuit that causes the lamp to light. The current that flows is tiny (1mA or so) and non-lethal but I find I can feel it when I use mine with bare feet even on our wooden floor. There is a story of a young apprentice (no, it wasn't me) who dropped one in a bucket of water, not wanting to get in trouble he simply replaced it in the tool box with predictable results when his boss used it again.

I still think they are a useful tool in many ways better (and easier) than a meter, but care is required in their use, gingerly tap the metal cap the first time you use it just to be sure, check it's not damaged, and, of course, don't drop it in water.

One last warning, just because the lamp does not light does not mean the circuit is safe to touch (same goes for a Voltstick, the battery may be dead), if in doubt open the incoming (double pole) breaker and put a sign on it not to turn on.

Yes, every time I use the thing, I am thinking about what is on the other side of that little bulb!

In Pattaya I used an IT cafe that had unearthed sockets. I quickly learned which computers not to use due to the unpleasant tingling whenever my leg touched the casing!

[thaibeachlovers]

Thanks to everyone for the valuable information given.

[snarky66]

Sorry this is late. Finally got somes pix of a 4 slot Square D breaker box.

I have Safe-T-Cut but never thought of using it as my main breaker (for de-energizing my system) I have blade fuses & a 100 Amp Mitsubishi breaker main.

This would have been perfect for this gentlemans project.

[thaibeachlovers]

Well, after several weeks working on the rewire/ replug/ reswitch/ replace lights/ install RCBO/ install consumer unit project, and having just reached the point of screwing on the last junction box, we're moving!

Its been an interesting and at times frightening project. I never knew just how bad an electrical system could be and still function!

I even discovered a small dead bat and a dead gecko with eggs, in a couple of fan control boxes!

What is scary though, is that the sister in law didn't even see why what they had needed upgrading!

When starting the project, I only intended replacing the rotten wooden plug boxes with plastic ones and decent plugs/ switches, plus installing a 2.5mm cable to bypass the 1.5mm cable that was in use for everything. However, like many things later regretted, it seemed like a good idea to upgrade the whole system, and several thousand baht later, that is what happened. Been a learning experience though, plus I am now the proud owner of many tools that will probably never be used again ( though there is a shed back home that needs wiring at some time in the future ).

Thanks for the information given by all the tradesmen contributing to the forum. I learned a lot from you.

Now, it will be time to read some books, watch DVDs, do some cooking and cruise the internet in a new location.

I do need a shower heater there though, so maybe I'll try my new skills with that. I've even got a couple of spare earth rods to use for it!

Thanks to all who contributed.