Using The Nuetral Line As The Earth/grounding

[Pilchard]

Got a third floor aparment that has been completly rewired with 3 pin power sockets.

Problem is the building has no earth/ ground conection.

I was thinking i would have to run a cable down to the ground floor and put in a grounding stake but a friend suggested connecting the earth to the nuetral spur !

Any comments on the safety of this idea ?

Thanks

[Pink Mist]

In an MEN system the neutral and ground are connected but only at the one point.

This is a really complicated question, I cant give you a safe answer, there are too many vaiables.

A point to consider is your plumbing system for a start.

[Crossy]

Elkangorito where are you???

Do you have an ELCB (Safe-T-Cut)? No - get one. Yes - a water pipe is better than nothing but.....

Do NOT use the neutral unless your system is actually DESIGNED to be a PEN (not MEN) system, which it certainly isn't.

Have look here http://www.crossy.co.uk/wiring/ click on 'help my rented house only has 2 pin outlets'

EDIT for information:-

MEN - Multiple Earthed Neutral, standard Thai system, neutral and earth are linked at each house, each house has a ground stake.

PEN - Protective Earth / Neutral. Used in parts of the UK, the neutral is used as the protective conductor, each house does NOT have a ground stake. An ELCB is vital in this arrangement.

[backflip]

In a word, "no". In several words, "no, it is not safe". "Ground" and "neutral" are two different things and, if you mix them up, you increase the probability of electrocution.

[Pilchard]

All the water system is plastic Thai pipe so no option there.

The place has been wired UK style, 30 amp ring main for sockets and 5 amp light ( i think), bathroom on seperate breaker.

Can some one explain PEN and MEN for me .Cancel that i see Crossy has explained already ,Cheers

Thanks for the quick responses gents

[Crossy]

I think you're stuck with running a ground wire

You may be able to conceal it in the cable chimney along with your incoming supply, water pipes etc

As an absolute minimum this wire will need to be 6mm² really should be 8 or 10mm² and you really MUST install an ELCB.

Elkangorito, our tame (and qualified) electrician will certainly have something to say on this, you there?? ..

[Pink Mist]

I think you're stuck with running a ground wire

You may be able to conceal it in the cable chimney along with your incoming supply, water pipes etc

As an absolute minimum this wire will need to be 6mm² really should be 8 or 10mm² and you really MUST install an ELCB.

Elkangorito, our tame (and qualified) electrician will certainly have something to say on this, you there?? ..

This is why I dont like to give advice Crossy, questions as basic as this, but how many variables are there.

We have a 2 day course in Oz for qualified sparkies to test installations for safety in regards to neutral earth connections and impedance

[Pilchard]

MEN - Multiple Earthed Neutral, standard Thai system, neutral and earth are linked at each house, each house has a ground stake.

If in the standard Thai sytem neutral and earth are linked at each house, would not me linking them at mine take advantage of next doors ground spike ( if he has one , haven't checked )

Where should the Safe T cut be place , after the meter and before the consumer box ?

[Crossy]

If in the standard Thai sytem neutral and earth are linked at each house, would not me linking them at mine take advantage of next doors ground spike ( if he has one , haven't checked )

Where should the Safe T cut be place , after the meter and before the consumer box ?

The problem is, if you don't actually KNOW how the system is wired, linking earth and neutral could prove lethal, PEN and MEN rely on solid, reliable grounding at the transformer

The Safe-T-Cut (ELCB, RCD, RCCB, GFI) goes immediately before your distribution board (after the meter) have a look at the 'consumer unit' page on the crossy website mentioned above

[Crossy]

This is why I dont like to give advice Crossy, questions as basic as this, but how many variables are there.

We have a 2 day course in Oz for qualified sparkies to test installations for safety in regards to neutral earth connections and impedance

Absolutely, that's why I never advocate anything other than installing an ELCB and running a ground stake.

Linking ground and neutral is only for qualified installers who know what they're doing and know how the existing system is wired.

[Pink Mist]

If in the standard Thai sytem neutral and earth are linked at each house, would not me linking them at mine take advantage of next doors ground spike ( if he has one , haven't checked )

Where should the Safe T cut be place , after the meter and before the consumer box ?

The problem is, if you don't actually KNOW how the system is wired, linking earth and neutral could prove lethal, PEN and MEN rely on solid, reliable grounding at the transformer

The Safe-T-Cut (ELCB, RCD, RCCB, GFI) goes immediately before your distribution board (after the meter) have a look at the 'consumer unit' page on the crossy website mentioned above

This subject is so basic, but is so filled with a capacity to injure someone if not carried out by someone competent.

So many things can go wrong, if you use a riser for consumer mains, ever thought of earthing the roof, these are the sorts of things we are trained in.

[Pilchard]

Just to make it more interesting, just got a phone call to say I have voltage on the nuetral Line !! Gotta love this place,eh

Got the boys to shut the lot off and check at the meter, they say the voltage is on the incoming nuetral.

I'll have to go and check it out myself tomorrow. Thanks for the info, will check out your site properly tomorrow Crossy,ta

I'm off down the pub, cheers

[Crossy]

Just to make it more interesting, just got a phone call to say I have voltage on the nuetral Line !! Gotta love this place,eh

Got the boys to shut the lot off and check at the meter, they say the voltage is on the incoming nuetral.

I'll have to go and check it out myself tomorrow. Thanks for the info, will check out your site properly tomorrow Crossy,ta

I'm off down the pub, cheers

The plot thickens.

PLEASE get a competent electrician to sort your system, do nothing yourself!!!!!

PM elkangorito if you're in Pattaya (that's where he was last time we spoke).

[Pink Mist]

Just to make it more interesting, just got a phone call to say I have voltage on the nuetral Line !! Gotta love this place,eh

Got the boys to shut the lot off and check at the meter, they say the voltage is on the incoming nuetral.

I'll have to go and check it out myself tomorrow. Thanks for the info, will check out your site properly tomorrow Crossy,ta

I'm off down the pub, cheers

The plot thickens.

PLEASE get a competent electrician to sort your system, do nothing yourself!!!!!

PM elkangorito if you're in Pattaya (that's where he was last time we spoke).

Sorry Crossy remember when we spoke I said its difficult to give advice

[Rinrada]

Carrying out selective measurement,soil restivity and earth ground loop resistance testing i have found in most "new"countries is treated almost as a joke...

Apart from in EU-US/Canada ,Auz-NZ and Japan.....seems its regarded as some sort of black magic but must always be taken as "deadly " serious especially...for You ..ho...

Simple way of getting round in in developing countries is of course only using 2 wires.....why spend money on a third.....seems crazy...mak mak......but....

In the old days it didnt seem to matter too much....couple of lights,a switch, power supply for maybe a radio/fridge/TV ....that was about it... until now.........

So to keep things simple ...an electric shower...get it installed properly but suggest a half decent spark because the at the end of the day its you who could end up extra well done......

Bit Of Info .......

When I move (one day ) to Chiangers I will be bringing over a load of various testing gear including my Flukes ....(bit of info follows )and maybe even set up a little testing company ...wife wants to be a bricklayer... and maybe keep busy.......but please find as follows some information on Testing procedures...but as said should get a spark involved ....its logical and staright forward ...but ...

so ...methods.....I use this on my training programmes.. ...could save yer life.....

Testing Methods 3- and 4-Pole Fall of Potential – standard earth ground testing using two ground stakes

4-Pole Soil Resistivity testing – determine soil resistivity using four ground stakes

Selective testing – without disconnecting ground rods, a technician can measure ground resistance using a combination of stakes and a clamp.

Stakeless testing – innovative solution using only clamps, instead of ground stakes, to measure earth ground loop resistance

Click on VIRTUAL DEMO.....and proceed.....

http://www.fluke.co.uk/comx/show_product.a...amp;locale=uken

[wpcoe]

I'm planning to upgrade my current condo in an older (15 year old?) building in Jomtien which has no earth/ground wiring, and buy in a new(er) building.

Do most reputable new constructions, like View Talay in Jomtien or North Shore in Pattaya, generally offer a truly grounded electric source for the condo units? I see they all have three-prong outlets on the walls, but do they actually have the supporting properly-grounded copper stake in terra firma? Or, is it like buying a pig in a poke even with higher-end new condo projects?

Or is my question too wide open to be non-laughable?

[elkangorito]

Got a third floor aparment that has been completly rewired with 3 pin power sockets.

Problem is the building has no earth/ ground conection.

I was thinking i would have to run a cable down to the ground floor and put in a grounding stake but a friend suggested connecting the earth to the nuetral spur !

Any comments on the safety of this idea ?

Thanks

Pilchard, is your apartment part of a condominium?

I think you're stuck with running a ground wire

You may be able to conceal it in the cable chimney along with your incoming supply, water pipes etc

As an absolute minimum this wire will need to be 6mm² really should be 8 or 10mm² and you really MUST install an ELCB.

Elkangorito, our tame (and qualified) electrician will certainly have something to say on this, you there?? ..

Sorry Crossy, with only 2 computers in the English staffroom, it's difficult to find a chance to get on site etc.

Anyway, I think this sounds like a "commercial" installation & therefore it falls outside the limits of a domestic installation. For example, I've noticed that some condo's have dual transformers supplying the establishment. I have not been able to ascertain whether the txers (transformers) are paralleled, whether they supply 2 separate branches within the establishment or if the "star point" is earthed. In any case, I agree with Bronco...this problem can only be solved by conducting a full inspection from the txers up & I certainly would NOT be doing anything to the existing wiring.

I'll go with Crossys' idea...get some ELCB's installed until alternative solutions can be varified.

Pilchard, DON'T TOUCH THE WIRING. DON'T EVEN LET THAI ELECTRICIANS ADD EARTH WIRES ETC. Get some ELCB protection & press the "press to test" button on a weekly basis & especially after an electrical storm. Make sure the ELCB is installed by a decent electrician. If you want some help, I live in Pattaya & am available to assist...just PM me should you require.

I'm planning to upgrade my current condo in an older (15 year old?) building in Jomtien which has no earth/ground wiring, and buy in a new(er) building.

Do most reputable new constructions, like View Talay in Jomtien or North Shore in Pattaya, generally offer a truly grounded electric source for the condo units? I see they all have three-prong outlets on the walls, but do they actually have the supporting properly-grounded copper stake in terra firma? Or, is it like buying a pig in a poke even with higher-end new condo projects?

Or is my question too wide open to be non-laughable?

Even though a voltage between the earth & the active pins may exist in an outlet (proof of an earth wire connected to the outlet), it doesn't necessarily mean that the earth is satisfactory. An "Earth Fault Loop Impedance test" must be carried out to ascertain if the earth system will be adequate. This test can be difficult to carry out in condo's or apartments but is easy with single domestic premises.

At the end of the day, seeing 3 pin electrical outlets in Thailand doesn't mean anything. Ensure you have Earth Leakage protection as a minimum standard in this case.

[Pilchard]

Just to make it more interesting, just got a phone call to say I have voltage on the nuetral Line !! Gotta love this place,eh

Got the boys to shut the lot off and check at the meter, they say the voltage is on the incoming nuetral.

I'll have to go and check it out myself tomorrow. Thanks for the info, will check out your site properly tomorrow Crossy,ta

I'm off down the pub, cheers

The plot thickens.

PLEASE get a competent electrician to sort your system, do nothing yourself!!!!!

PM elkangorito if you're in Pattaya (that's where he was last time we spoke).

Appreciate your concern mate , believe me ,I do have a healthy respect for electricity.

Going to run a cable to the ground floor and a stake today.

Went round the system with a sparky this morning, all is good on my side of the meter.

The problem of juice on the nuetral is the next problem, traced it back to the buildings main 3 phase meter, and then went to all the shop houses in the row ( 6 in all ).

Every single unit has voltage on the nuetral !! and no one seems to care !! I demonstrated the problem with a lecky screw driver and got told " it's always been like that "

I'm surprised the whole block hasn't burnt down yet .

The units have their own transformer out side and i guess the nuetral should be clean from there.

Anybody got any suggestions on tracing who has got their wires crossed. ?

[chownah]

Doesn't this show a lack of grounding of the neutral? I probably shouldn't comment on this since I'm a 3 phase idiot.

Chownah

[Crossy]

Doesn't this show a lack of grounding of the neutral? I probably shouldn't comment on this since I'm a 3 phase idiot.

Chownah

Could be an iffy neutral ground, or a heavy load imbalance or both. If he's lighting a neon driver that's over 70V or so on the neutral, BIG problem.

[elkangorito]

Neutral to Earth voltages can be caused by a number of things;

* Corroded electrical boxes or conduit.

* Wires, electrical boxes, or motors in wet or damp areas.

* Accumulation of dust on or around electrical equipment.

* Broken insulation, exposing wires.

* Insulated wires wrapped around metal pipes (induction).

* Unbalanced electric load.

* Harmonics.

* Bad wiring connections.

In THailand, I suspect bad connections & High Tension "creepage" could be major suspects whilst earth leakage (within motors etc) is another candidate. You are sharing your neutral with others so the problem(s) could be coming from anywhere.

Of course, the way to fix this problem is to find the cause but since there could be many causes, the best thing to do is earth the neutral.

Pilchard, you say that you are going to install an earth. BE VERY CAREFUL!!! Badly installed earths have killed many people in the past...usually near the earth stake (rod).

Really, there is only one solution...the whole block of apartments must be re-wired as an MEN system with only 1 earth. When people start doing their own thing with earths, that's when people get hurt.

I advise against what you are about to do UNLESS you can get the whole block re-wired to a safe & consistent standard. Preferrably, it will be re-wired as an MEN installation, which will virtually eliminate Earth to Neutral voltages.

[chownah]

I'm having a hard time thinking of how dust on or around an appliance could cause a neutral to earth voltage....can you give a scenerio?

Doesn't the term "neutral" indicate that at some place in the overall circuit (all the way back to the generator perhaps) the wire is earthed?

Chownah

[Pilchard]

Hi Gents

Let me try to give you a better picture of the building .

These are standard 4x12 meter , 3 storey shop houses. 6 shop houses in a row (terrace) , 3 rows , 18 shops in total.( all in a line along a main road)

At one end there is a power pole with a big transformer. 4 cables are slung along the front of all the shops with connections down to the individual meters.

After some snooping around I have now seen that each of the shops have an earth stake, must have been added as an after thought becuase the stakes are drilled at the front of each shop, with a wire passing through a hole in the wall and connected to the nearest power socket !

There is no direct line from the stake to the consumer box .

The appartment i have rented is on the top floor of one shop house. The shop has 3 phase and my app has a sub metered single phase running from a 60 amp breaker in the shop below , up to the consumer box in my place.

All of the wiring on the top floor is new and is completly seperate from the shop below.

Why would it not be safe to run a seperate earth spike for the upstairs consumer box ?

sorry if that was a bit long winded

PS

Nice website Crossy

[elkangorito]

I'm having a hard time thinking of how dust on or around an appliance could cause a neutral to earth voltage....can you give a scenerio?

Doesn't the term "neutral" indicate that at some place in the overall circuit (all the way back to the generator perhaps) the wire is earthed?

Chownah

The neutral in many countries is not always earthed. It all depends upon the system that is employed eg TT, TI, TN etc. I won't bore you with the details of the meanings of these but the word "neutral" indicates that it is not the active (supply) conductor.

Dust or moisture can track from the active parts of an appliance to the neutral & thereby create a small current to neutral (quite often in switches etc). Quite often, this current is so small that it may not trip a protective device (circuit breaker, fuse etc).

As Crossy suggested, the most common cause of a neutral to earth voltage is an "out of balance" current in the neutral. This is common in multi-phase systems. In a house (single phase), it is most probably caused by a shared neutral or "out of balance" feedback from a multi-phase system. If the neutral is broken, very high voltages can be expected along with equipment failure & personal injury. For this reason, the neutral must never be switched unless the active is switched with it.

Have you seen how the power cables on power poles are a complete mess (cables twisted around & over each other)? This situation can lead to voltages being "induced" into the affected conductors...another possible reason for a voltage from neutral to earth.

At the end of the day, earthing the neutral will mostly solve the problem...but of course, this must be done properly.

[Pilchard]

"Juice on the nuetral"

Some one has suggested that one of the shops may have a piece of three phase machinery or a motor wired wrongly !

Could that cuase this

These are the test readings from the 3 phase input to my building.

L1 to L2 =390v

L1 to L3 =390v

L2 to L3 =390v

L1 to N=225v

L2 to N=225v

L3 to N=225v

N= earth 255v

L1-earth 386v

L2- earth 375v

L3-earth 006v (six volts)

[elkangorito]

Hi Gents.

At one end there is a power pole with a big transformer. 4 cables are slung along the front of all the shops with connections down to the individual meters.

After some snooping around I have now seen that each of the shops have an earth stake...with a wire passing through a hole in the wall and connected to the nearest power socket! There is no direct line from the stake to the consumer box .

The appartment i have rented is on the top floor of one shop house. The shop has 3 phase and my app has a sub metered single phase running from a 60 amp breaker in the shop below , up to the consumer box in my place.

Why would it not be safe to run a seperate earth spike for the upstairs consumer box ?

sorry if that was a bit long winded

PS

Nice website Crossy

Hi Pilchard. Comments as follows. BTW, I've edited your above comments to reduce post window size.

With 2 earth stakes in relative close proximity to each other, a potential can be created between them if there is current flowing in at least one earth conductor. Also, this can set up "circulating currents" within the earthing conductors & may be detrimental to the wiring & humans.

If the earth conductor from the existing earth stake is connected to an earth bar in the shop consumer board (as it should be because this board is the Main Consumer Board), maybe you could run an earth cable from your sub board to this Main Board?

What size is the earth cable that connects to the earth stake?

Years ago when Tesla was electrifying cities, he had enormous problems with people & horses getting electrocuted as they walked past a multi earthed installation. This was solved by only having one main earth per installation.

[Crossy]

L1 to L2 =390v

L1 to L3 =390v

L2 to L3 =390v

L1 to N=225v

L2 to N=225v

L3 to N=225v

N= earth 255v

L1-earth 386v

L2- earth 375v

L3-earth 006v (six volts)

Bl00dy He11 mate. Which phase is your apartment wired to?

Looks like L3 may be grounded (and the neutral isn't), I seriously suggest that your sparks contacts the supply company NOW.

EDIT Until you fix the interesting neutral configuration do NOT put any grounding in. If you're on anything other than L3 you're going to overstress the insulation in any grounded equipment.

[elkangorito]

"Juice on the nuetral"

N= earth 255v

L1-earth 386v

L2- earth 375v

L3-earth 006v (six volts)

Am I reading this correctly?

It certainly looks like L3 is broken somewhere...but where?

Or maybe someone has exchanged L3 for neutral somewhere...in the connections on a 3 phase motor perhaps? If L3 was connected to a neutral, it would immediately short out...unless the neutral is broken somewhere, in which case it would then be an active conductor ie N= earth 255v.

I love Thai wiring

I think you need more than an earth stake to fix your problems. And now that you have revealed the voltages, I ABSOLUTELY WOULD NOT BE PUTING AN EARTH STAKE IN ANYWHERE...until this problem is solved.

[Pilchard]

Thanks guys, I will for sure put the earth spike on hold until this is sorted.

With my panicky running around and waving of multi meters I have managed to get the landlord worried enough to get involved.

He has made some calls and tells me that some one will come tomorrow to check out all the units to try and find the fault.

My money is on the tyre shop, loads of 3 phase gear in there.

My place is hooked up to L1 .

If the earth conductor from the existing earth stake is connected to an earth bar in the shop consumer board (as it should be because this board is the Main Consumer Board), maybe you could run an earth cable from your sub board to this Main Board?

What size is the earth cable that connects to the earth stake?

The earth conductor is at the front of the shop and conected to a socket, the main board is at the back of the shop and has the a earthbar with earth leads going to it. No dircect connection to the stake.

Earth cable is 6mm from the stake to first socket and 5mm in the walls.

Will let you know how it turns out, cheers

[dhrobertson]

Protective Multiple Earthing is normal in Thailand. In this case, the star point of the transformer is bonded to ground and also forms the neutral. As you now have effectively a combined earth and neutral (the fourth cable in a 4 wire 3 phase system) this now called a PEN (protective earth and neutral). The PEN is bonded to ground and every thrd pole to reduce the dangerous situation of an open neutral. At your apartment, you need separate ground (earth) and neutral cables internally in the building.

You should get your electrician to do the following. Fit a ground electrode (10 feet long 5/8 inch diameter, copper clad) and attach to the NEUTRAL bus at the consumer unit or main distribution board using cable not less than half the diameter of the incoming feeders. Link the neutral bus to the ground bus(s) using the same size cable. This produces a TN-C-S system. The link between neutral (PEN) and ground should only be at one place in the system. If this is at the main distribution board (MDB), then you can just run a ground cable from the MDB ground bus to your ground bus at the consumer unit.

For the record, you should see about 380/400V between any two phases and about 220/230 between any phase and neutral (PEN). The nrutral (PEN) should be about 0V. I suspect you have an induced voltage in the neutral

I do not recommend a single RCCB (residual current circuit breaker) to protect the whole apartment. It is better to fit an RCBO or ELCB on each circuit supply a socket outlet or water heater.