What's a stolen neutral and how to fix it.

[AJBangkok]

A couple of years ago I had my condo renovated taking it back to bare concrete and doing a completely new fit out including completely new wiring. The electrical work alone was over B1 million not including all the lighting fixtures and sockets, plugs etc.

 

Recently I had a problem with a plug in the kitchen which just went dead. I called in an electrician and to cut a long story short the problem turned out that my wife had turned off the breaker for a water heater in the guest bathroom and by doing that it turned off that particular plug.

 

Now the kitchen is supposed to be on its own circuit and every other plug is to my knowledge. The guest bathroom is over 30 meters away ( I have a big condo ) so why a plug in the kitchen would be connected to a guest bathroom 30 meters away is anyone's guess.

 

The real problem is that when the electrician was inspecting the box he found that the 3 RCBO's I have for the bathroom water heaters were not connected. They all have curly wire that stretches coming from them that instead of being connected to the neutral???? ( I'm not sure about this) were left unconnected and just hidden behind other wires in the box. The fuses all still worked but the safety trip didn't .

 

The electrician connected them but within a few minutes they all tripped and continued to trip every time they were reset. The electrician said the company who wired the house had been lazy and had "stolen neutrals " and it would require major work to fix. He ended up unattaching the curly wires so the breakers wouldn't trip but I'm now concerned it's dangerous 

 

Could someone explain what all this means and what are my options. I am a bit scared to turn on the hot water heaters as  I don't want to risk electrocution 

 

thanks 

alex 

 

 

[Crossy]

A borrowed or stolen neutral is when two or more live feeds share a single neutral to return to the board.

 

Your RCBOs should have a neutral going in (the curly) and a neutral going out (to the water heater), I suspect neither are actually connected.

 

Fixing them could prove fun. The first thing to do is identify where the neutrals in your water heater actually go in the box. If you're lucky they just go to the neutral bar, if you're unlucky they get shared by outlets and the like.

 

As to hazard. Are the water heaters grounded? If so operating them with no earth-leakage protection isn't going to kill you but they really need sorting.

 

Since you have located a sparks who understands what a borrowed neutral is, could you get him back to at least fix the water heaters?

 

[AJBangkok]

Thanks Crossy, I think they are shared as he tried a few of the blue wires that were supposed to be coming from the water heaters connecting to the box and they did not work. My sparky is from the UK and he's not cheap but as this is a safety issue I will see what he can do. He did mention something about a " process of elimination " that could work but could be very time consuming but I guess that would be better than rewiring the entire condo or at least the 3 water heaters which would probably be a nightmare. 

 

The 2 upstairs bathrooms are also 30 plus meters apart and the labels on the switch box indicate the the 2 water heaters for upstairs are on the same RCBO even though the 2 bathrooms or at least their sockets are on different circuits.

 

 

[bankruatsteve]

The danger from a borrowed/shared neutral is the potential for over-current in the neutral and which is not detected by a MCB.  For example, if two water heaters on separate MCBs but sharing a neutral return are both operating and drawing say 25 amps each, both of the 32 amp MCB would not complain but that would put 50 amps on the neutral and most likely well over it's rated capacity.  If a lighting circuits borrow a neutral, it's not good but also not especially dangerous due to the low current draw.  Heaters and outlets that share a neutral can be very dangerous.

 

Finding such is really just a matter of knowing how to use an ohmmeter and the tedious process of elimination by checking every wire and connection in every suspect circuit.  Hopefully you won't need to break open ceilings or walls to find it (them),  but find it you must.  Good luck.

[wayned]

"Shared neutrals" can be very expensive!  My first divorce was caused by a "sharded neutral" and believe me to cost a lot to "fix"!

[RichCor]

12 hours ago, AJBangkok said:

The real problem is that when the electrician was inspecting the box he found that the 3 RCBO's I have for the bathroom water heaters were not connected. They all have curly wire that stretches coming from them that instead of being connected to the neutral???? ( I'm not sure about this) were left unconnected and just hidden behind other wires in the box. The fuses all still worked but the safety trip didn't .

 

The electrician connected them but within a few minutes they all tripped and continued to trip every time they were reset. The electrician said the company who wired the house had been lazy and had "stolen neutrals " and it would require major work to fix. He ended up unattaching the curly wires so the breakers wouldn't trip but I'm now concerned it's dangerous 

 

 

11 hours ago, Crossy said:

Your RCBOs should have a neutral going in (the curly) and a neutral going out (to the water heater), I suspect neither are actually connected.

 

I'm a little concerned your 'electrician' doesn't really understand how these RCBOs work if, as Crossy surmised, he just connected the Neutral pigtails and didn't bother moving the paired neutral wires for each circuit over as well  ...so of coarse they tripped the RCD as it detected an unbalanced load that was supposed to be connected to the RCBO LIVE and NEUTRAL screws.

 

As most electricians run 2 or 3 cores from the DB to every plug and appliance, it's very rare to find actual 'borrowed' neutrals except when someone installs a 3-way (dual-location) light switch and get's stupidly lazy.

[maprao]

Can you find the sparky tgat did the job for 1M and get him to fix it.???

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[AJBangkok]

Thanks for the replies guys. 

 

As as far as finding the original electrician. It would be possible but frankly this is a serious safety issue and if they didn't know how to do it right the first time I don't want put my family at risk a second time by using inept people to try to fix the issue.

[Forkinhades]

Your heaters should have ELCB installed already. If not, just install an ELCB local to your heaters, whislt your finding your borrowed neutrals.

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[shaemus]

Your "Stolen" or borrowed neutral can be explained quite easily and is easy to rectify for a competent sparkie.

 

The Rcd or RCBO will trip if a current imbalance occurs, e.g. you touch the live on a piece of equipment and some of that current passes through you , the device will trip as it senses the current passing through it has gone out of balance. Similarly if you borrow the neutral lets say for a lighting circuit , again a current imbalance will trip the device.

 

It should be very easy to find the transposed neutrals in your switchboard, i am going to assume that they aren't labeled or numbered. Confirm that you are certain of the piece of equipment you are going to isolate is correct by verification and testing, when de energised and confirmed connect the neutral and earth together. then go back to the switchboard and test the suspected earth and neutrals with continuity meter when continuity is found then disconnect the joint at the water heater then go back to the switchboard test again to confirm the result is different (no continuity) and there you go. label the conductors correctly. and then reconnect and energize. if you still have a  trip occuring after this then you either have a different fault or someone has borrowed a neutral. 

 

(edit) i have just re read your comments, do you have a photo of your DB with the escutcheon plate removed?

 

I can only assume that your Sparkie has connected the fly leads the common neutral link in the DB, you need to identify the three circuits as i explained above and then connect the fly leads to the corresponding neutral for the circuit. not to the common neutral, of you can take a close up to the rcbo model that would be helpful too.

Edited August 28, 2017 by shaemus
more info

[Crossy]

54 minutes ago, shaemus said:

you need to identify the three circuits

The problem is that Thai sparkies have an annoying habit of just tying in to any old neutral in a box. So there could be two circuits sharing a common neutral back to the board from some location up in the attic space. Very difficult to find 

[Formaleins]

These bodges are a real PITA, I discovered that the sparks that did our wiring had borrowed a neutral when they wired a two way switch for lighting connecting a downstairs and upstairs light - Luckily I had a decent safety box as I had switched off what I thought was the live side of the circuit at its breaker, only to find it was still live when I went to cut the cable!

[Elkski]

Are wires in Thailand usually a 2or 3  bundle w/ ground?

Assuming this is true plenty of neutrals should be in the main box. Tell me if this sounds like a game plan.  Remove all neutrals from the neutral bar. Test for continuity between each neutral.  Yes that means.  So put red lead on the left most neutral , then black lead to touch and test to all the others.  Then move red down one and test all the remaining  to the right hopefully all are separate. Then for be out which ones go to the Heater's and hook up to RCBO correctly.  Test.   May not be so hard.  

Edited August 28, 2017 by Elkski

[catman20]

On 8/27/2017 at 8:57 AM, AJBangkok said:

Thanks for the replies guys. 

 

As as far as finding the original electrician. It would be possible but frankly this is a serious safety issue and if they didn't know how to do it right the first time I don't want put my family at risk a second time by using inept people to try to fix the issue.

its really a pain in the ass you spend all that money thinking your getting a job done right and in short they just bodge it up, everything ive had dont in my house has been done a least 2 or 3 time before its been done to a satisfactory standard. its very annoying and very expensive. as for getting the original man back thats a joke ive never had any luck getting any thai back to fix or redo something, they just turn there phones off when you try to get them back, as a friend of mine say they like to hit and run.  good luck

[catman20]

On 8/27/2017 at 8:57 AM, AJBangkok said:

Thanks for the replies guys. 

 

As as far as finding the original electrician. It would be possible but frankly this is a serious safety issue and if they didn't know how to do it right the first time I don't want put my family at risk a second time by using inept people to try to fix the issue.

i suspect hes like all the others here, ull never get him back even if you wanted to. good luck.

[Crossy]

If you fancy giving this a go yourself here are some guidelines, all are power-off tests so you should be safe.

 

You will need;-

A simple continuity tester (multimeter or bulb and battery).

A long wire.

 

• Turn off the power and remove the lid from your distribution board.
• Count how many neutrals you have, is it the same as the number of outgoing lives (probably not)?
• Remove the neutrals from the neutral bar.
• Check that they are all separate (as Elkski describes above). If you find two linked mark them as such for fixing later.
• Connect your long wire to the neutral at the water heater.
• Check for continuity to the neutrals in the board.
• Connect the now identified neutral to the outgoing neutral terminal of the RCBO (and connect the RCBO pigtail to the neutral bar)

 

• Repeat for the next water heater.
• Put the other neutrals back in the neutral bar.

 

Whilst you have the lid off it's worth checking that none of the neutrals have continuity to the ground bar (our sparks linked N-E in an outlet for some reason, caused me all sorts of headaches).

 

• Turn the power back on.

 

• If an RCBO trips the neutral is likely borrowed by another circuit.
• Turn off all the breakers except the RCBO, hopefully it won't trip.
• Turn the breakers on one at a time until the RCBO trips.

 

An easy fix is to move the live from the breaker that causes the trip to the RCBO that trips, but watch the load. Or you can go a hunting (good luck with that in the spaghetti that's a Thai home).

 

[jacko45k]

Do the water heaters not have their own RCB fitted locally? Most shower type units do. If they have test them, and it should alleviate your concerns about them.

 

As to your wiring, same same. I turned off my main bedroom water heater breaker and the lights over my bar went off too!

[AJBangkok]

22 hours ago, shaemus said:

Your "Stolen" or borrowed neutral can be explained quite easily and is easy to rectify for a competent sparkie.

 

The Rcd or RCBO will trip if a current imbalance occurs, e.g. you touch the live on a piece of equipment and some of that current passes through you , the device will trip as it senses the current passing through it has gone out of balance. Similarly if you borrow the neutral lets say for a lighting circuit , again a current imbalance will trip the device.

 

It should be very easy to find the transposed neutrals in your switchboard, i am going to assume that they aren't labeled or numbered. Confirm that you are certain of the piece of equipment you are going to isolate is correct by verification and testing, when de energised and confirmed connect the neutral and earth together. then go back to the switchboard and test the suspected earth and neutrals with continuity meter when continuity is found then disconnect the joint at the water heater then go back to the switchboard test again to confirm the result is different (no continuity) and there you go. label the conductors correctly. and then reconnect and energize. if you still have a  trip occuring after this then you either have a different fault or someone has borrowed a neutral. 

 

(edit) i have just re read your comments, do you have a photo of your DB with the escutcheon plate removed?

 

I can only assume that your Sparkie has connected the fly leads the common neutral link in the DB, you need to identify the three circuits as i explained above and then connect the fly leads to the corresponding neutral for the circuit. not to the common neutral, of you can take a close up to the rcbo model that would be helpful too.

Thanks very much for the advice. I am traveling this week so I won't get a chance to remove the internal panel and take a pic but I will do so when I am back 

[AJBangkok]

2 hours ago, Crossy said:

If you fancy giving this a go yourself here are some guidelines, all are power-off tests so you should be safe.

 

You will need;-

A simple continuity tester (multimeter or bulb and battery).

A long wire.

 

• Turn off the power and remove the lid from your distribution board.
• Count how many neutrals you have, is it the same as the number of outgoing lives (probably not)?
• Remove the neutrals from the neutral bar.
• Check that they are all separate (as Elkski describes above). If you find two linked mark them as such for fixing later.
• Connect your long wire to the neutral at the water heater.
• Check for continuity to the neutrals in the board.
• Connect the now identified neutral to the outgoing neutral terminal of the RCBO (and connect the RCBO pigtail to the neutral bar)

 

• Repeat for the next water heater.
• Put the other neutrals back in the neutral bar.

 

Whilst you have the lid off it's worth checking that none of the neutrals have continuity to the ground bar (our sparks linked N-E in an outlet for some reason, caused me all sorts of headaches).

 

• Turn the power back on.

 

• If an RCBO trips the neutral is likely borrowed by another circuit.
• Turn off all the breakers except the RCBO, hopefully it won't trip.
• Turn the breakers on one at a time until the RCBO trips.

 

An easy fix is to move the live from the breaker that causes the trip to the RCBO that trips, but watch the load. Or you can go a hunting (good luck with that in the spaghetti that's a Thai home).

 

 

Thanks very much Crossy. I think this may be a bit above my level of competence and it's safer to get my sparky to do it. I am going to be travelliing this week so I will try to get an appointment with him when I'm back and show him this post. 

[AJBangkok]

54 minutes ago, jacko45k said:

Do the water heaters not have their own RCB fitted locally? Most shower type units do. If they have test them, and it should alleviate your concerns about them.

 

As to your wiring, same same. I turned off my main bedroom water heater breaker and the lights over my bar went off too!

To be honest I'm not sure. 2 are Siemens and the 3rd is stiebel. They are top of the line units but none of them have a 'reset " button on the exterior and I have to open the units to see. 

[KittenKong]

2 hours ago, catman20 said:

its really a pain in the ass you spend all that money thinking your getting a job done right and in short they just bodge it up

 

Par for the course in Thailand. Bodging things and cutting corners seems to be common practice in every profession and trade here, and how much or how little you pay for the job doesn't seem to have much bearing on how good or bad it is.

 

So hard to find any sort of professional here who is actually professional and who really knows his job.

[Crossy]

23 hours ago, shaemus said:

I can only assume that your Sparkie has connected the fly leads the common neutral link in the DB, you need to identify the three circuits as i explained above and then connect the fly leads to the corresponding neutral for the circuit. not to the common neutral, of you can take a close up to the rcbo model that would be helpful too.

My Bold.

 

Whilst I see where you're coming from this is incorrect.

 

The RCBO will have two terminals on the outgoing end, L and N, these go to the load. The pigtail goes to the main neutral bar in the distribution board (to provide the neutral to the load via the RCBO).

 

EDIT Like this, note that this RCBO has a supplemental earth connection, not all do.

 

 

[jacko45k]

1 minute ago, AJBangkok said:

To be honest I'm not sure. 2 are Siemens and the 3rd is stiebel. They are top of the line units but none of them have a 'reset " button on the exterior and I have to open the units to see. 

Sounds like they do not as usually a test/ reset facility is accessible.

[Elkski]

Crosby explained a way on how to find  the correct neutral and hot wires for the heaters. I should have added this in to my instructions.  I still think it's a good idea to make sure all neutrals are not joined somewhere.   

I also should have said to turn off all  power.   Rather than running a long wire to the heaters if you know the heater load wires like I think you do you can do a continuity test to find the corresponding neutrals.  If heater is analog and temp selector is on the neutral and hot should be joined in heater and make a circuit you can test.  

[bankruatsteve]

32 minutes ago, Elkski said:

Crosby explained a way on how to find  the correct neutral ...

And Bob Hope will explain the search for live.

[Crossy]

4 minutes ago, bankruatsteve said:

And Bob Hope will explain the search for live.

 

 

 

[Elkski]

Bob must have been a gentleman! Unlike Crosby. 

[Crossy]

I have no bee.

[shaemus]

My apologies for my mistake, i tried to rectify the error but i could not edit the post again. 

 

Basically mate, you need a sparkie. A real one, i could write here for hrs on what what you should do, but its quite complicated. Fundamentally you need to ensure your installer hasn't messed up by mixing up the pairs+E (L&N+E) from your DB to the RCBO, it doesn't really matter about the earth conductor for this operation (you might not even have one, but that is a different argument) it could be a case hopefully of the neutral conductors for each hot water being mixed up. that is your best case. worst case. someone has borrowed a nuetral.

 

Confirm the neutrals are in the right terminal before you go any further. 

 

As a previous poster said: you could also install and RCBO next to your water heater, As for ELCB's they are not very common .

Edited August 29, 2017 by shaemus
spelling

[Crossy]

3 minutes ago, shaemus said:

As a previous poster said: you could also install and RCBO next to your water heater, As for ELCB's they are not very common .

To clarify, the term "ELCB" is usually reserved for the old Voltage Operated ELCB (VOELCB) which work in a different way to the RCD (differential) device.

 

However, the term ELCB gets used in the non-technical world to refer to an RCD and any "ELCB" you see in the domestic market will actually be an RCD.