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Weird electrical problem!

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  • bankruatsteve
    bankruatsteve

    Critters getting into an outside box can put a fault between L and E.  Sometimes large enough to energize the ground system.  After frying, the fault can go away.  In my case, I had geckos in the box

  • Is your system MEN (N-E link in the box)? If not sure post a photo of the box with the lid off (care please).   An open neutral between you and the transformer could lead to this kind of iss

  • Not linked. I know it should be, but fear the potential (55) consequences of attempting to do it myself.   No way is any local Chan getting anywhere near it!

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  • Author
22 minutes ago, xtrnuno41 said:

I measured the voltage between myself and the sink, at 200volts! I

 

You put one lead of the meter on the sink and the other you hold in your hand?

you were on bare foots then? Amazing measuring.

You switched off power (live?) and still measure it in same way. Even on a return valve in plastic pipe water supply.

My best guess then would be, the water is conducting electricity. Maybe even built up static electricity in the water system.

Water in Thailand is not Ph 7. More like Ph 4 (acid) or so and then it can conduct electricity.

As you grounded all, as you said, it should flow away but doesnt. Ground properly working then? 

The electricity can then come from another device in another group and has a fault in it. The group protection in it doesnt work, you have differential circuit breaker's in your box? But has to be a device connected with the water, your shower? 

Next day you go back and all gone, so fault erased, maybe for a short or longer time.

Yes, one meter probe in my fingers, other on the sink, dry rubber shoes on a dry tiled floor. Meter has 9k ohm/v impedance,  50uA fsd so perfectly safe.

 

Water conducting electricity...yes I agree, but from where when power is off? Not any of the water heaters.

 

Static? Unlikely to maintain a steady voltage, grounding it should leak the charge away.

 

I think @Crossy has it, a PEA fault which they have found and corrected. I cannot conceive how I would explain the problem to them or seek to know the answer, my Thai is not up to it and no Thai I know would begin to understand! 

  • Author
14 minutes ago, Crossy said:

I don't see an RCD / RCBO ???? 

 

Legrand breaker on the right is a 30mA RCD. None in the main box.

IMG_20210915_165648.thumb.jpg.f0776e5aefdba72281258ded6e1dc988.jpg

  • Author
3 hours ago, Rookiescot said:

Just wondering if the earth spikes could be the source of the voltage?

With heavy rain and a raised water table those "earths" might be conducting between each other.

I had similar thoughts, but can't get my head round it. And I have only one spike, and I would agree a few volts possible, even likely, but 200? Free power folks, just connect across two spikes and you can run your EV free, forever!

On 9/14/2021 at 12:04 PM, Grusa said:

Does anyone have any idea how this could happen?

Had the same thing get 30v on any metalwork in the house when the streetlights  turn on  out in the road every evening, a  quick chat with Crossy determined the streetlights were at  fault, still waiting for it to be rectified by the leccy comanpy

15 minutes ago, Grusa said:

I had similar thoughts, but can't get my head round it. And I have only one spike, and I would agree a few volts possible, even likely, but 200? Free power folks, just connect across two spikes and you can run your EV free, forever!

Does it  only  happen at certain times? mine was a s soon as the streteliughts  switched on by photocells  out in the road, check neutral to earth 30v, as soon as they flick off  in the morning, nothing 0v

1 hour ago, Grusa said:

Yes, one meter probe in my fingers, other on the sink, dry rubber shoes on a dry tiled floor. Meter has 9k ohm/v impedance,  50uA fsd so perfectly safe.

I'm just wondering how you could get 200V between your finger and sink while you were standing on your dry rubber shoes !!!!!!! 

 

4 hours ago, Rookiescot said:

If the supply is underground and the insultation was broken then with heavy rain you could find the earth spikes are picking up a voltage?

That's a possibility. Especially where there is no multiple earth rods and earth is not linked to N. But voltage can't be gone next day if that's the case. 
 

 

  • Author
54 minutes ago, The Theory said:

I'm just wondering how you could get 200V between your finger and sink while you were standing on your dry rubber shoes !!!!!!! 

 

Capacitive load.

1 hour ago, The Theory said:

That's a possibility. Especially where there is no multiple earth rods and earth is not linked to N. But voltage can't be gone next day if that's the case. 
 

 

It could if the water table drops. I guess. Honestly I am trying to think out of the box as to how this could be happening.

Would really like to get it resolved because I worry a child could be the next to get a belt ????

30 minutes ago, Rookiescot said:

It could if the water table drops.

Right, I never trust under ground power cables anyway ????. There was a case in Redondo Beach, CA near power plant. People could even feel it while taking shower (but in that area copper pipes used) I guess the best is multiple ground rods if possible and linked to supply N (professionally installed, using salt and coal). 


 

7 hours ago, The Theory said:

I guess the best is multiple ground rods

There are  two types of  rods  available here, the normal  maybe 10mm size  rod  copper  coated but  also a CROSS  shaped  one which are WAY  bigger  thicker and used by PEA, I have the second type  in some places

------I have an outside utility area, fully covered and wired by myself---------

 

Are you a qualified Electrician 

On 9/14/2021 at 12:04 PM, Grusa said:

so I deferred the job until this morning.

Are you sure it was not just all a dream ?:unsure:

5 hours ago, Rampant Rabbit said:

There are  two types of  rods  available here, the normal  maybe 10mm size  rod  copper  coated but  also a CROSS  shaped  one which are WAY  bigger  thicker and used by PEA, I have the second type  in some places

This is what I would do:

If you want near 0 resistance, need to dig the ground like a cylinder (at least 20cm dia.) about 2 meters (or deeper) then hammer a 3m (or longer) rod in the hole. Then fill the 2m cylinder by mixture of crushed coal and salt. Do the wire and then cap the hole. Every once in a while you may need to top off (add more salt on the top) and check the clamp and cable for best connection. Be careful while you checking the clamp. I recommend non-conductive gloves. Especially if there is only a single rod or no RCB. If you can make at least a few of this around your property. I would make a drip system to keep the coal/salt all seasons wet. 
 

13 hours ago, The Theory said:

Right, I never trust under ground power cables anyway

Stuxck  mine underground a  metre deep, NYY  cable 16mm and then also inside hdpe piping 32mm

On 9/14/2021 at 12:04 PM, Grusa said:

I touched the stainless steel sink, and I got a shock

Is the metalwork of the sink earthed?

 

On 9/14/2021 at 12:04 PM, Grusa said:

Even the brass non-return valve in the blue plastic water supply line showed 200v.

Your electrical problem is probably due to an electrical fault where the live is in contact with the water supply. Is the water from the utility or from your own well?

If from your own well then you have some faulty equipment. If water is from the utility supply then it is probably someone in another house nearby who is without a ground.

  • Author
3 hours ago, Muhendis said:

Is the metalwork of the sink earthed?

 

Your electrical problem is probably due to an electrical fault where the live is in contact with the water supply. Is the water from the utility or from your own well?

If from your own well then you have some faulty equipment. If water is from the utility supply then it is probably someone in another house nearby who is without a ground.

Sink earthed, yes.

 

Water is from Mubaan borehole and high level storage tank. Its about 250 metres away.

 

Because of Covid we have no very near neighbours.

No one has mentioned that adding a single ground rod in an old unearthed moobahn makes you the only ground (earth) for a large area and who knows how many properties?

 

On the other hand, there certainly is an earth connection somewhere, maybe you haven’t noticed it. Even my little village in Issan (under PEA) added ground rods on the supply poles many (5?) years ago.

 

Good luck. Be careful!

23 minutes ago, Kwarium said:

No one has mentioned that adding a single ground rod in an old unearthed moobahn makes you the only ground (earth) for a large area and who knows how many properties?

No body has mentioned it because it is not true.
 

If the supply is TT (that is your unearthed moobahn) you earth your property only. You do not link your earth to the incoming neutral.

 

So your house is earthed completely independent of others.

23 minutes ago, Kwarium said:

On the other hand, there certainly is an earth connection somewhere, maybe you haven’t noticed it. Even my little village in Issan (under PEA) added ground rods on the supply poles many (5?) years ago.

You have a TNCS supply so every house should have a MEN link.

 

 

30 minutes ago, sometimewoodworker said:

No body has mentioned it because it is not true.
 

If the supply is TT (that is your unearthed moobahn) you earth your property only. You do not link your earth to the incoming neutral.

 

So your house is earthed completely independent of others.

You have a TNCS supply so every house should have a MEN link.

 

 

I don't think that's right.

If you were to use Kirchoff's Law and draw up all the potential current loops for the current to get back to the transformer of an O/C neutral, if the only ground rod in the moo baan has a path of least resistance, then there would be a high current flow.

The current has to try and get back to the transformer somehow, any way. Me thinks.

39 minutes ago, carlyai said:

I don't think that's right.

If you were to use Kirchoff's Law and draw up all the potential current loops for the current to get back to the transformer of an O/C neutral, if the only ground rod in the moo baan has a path of least resistance, then there would be a high current flow.

The current has to try and get back to the transformer somehow, any way. Me thinks.

I have no idea what you mean by “O/C neutral” however in a correctly designed independently earthed TT system that will have an RCBO (I said correctly designed and RCBOs are required for that here) any imbalance L/N will be cut by the RCBO so virtually no current flow. 
 

Of course we can only discuss correctly configured systems, as the ways to wrongly configure are many and various. It seems that even more stupid and dangerous ways are being discovered by talented idiots all the time.

 

Correct earthing is often not simple and the idea that multiple earth rods randomly banged in without knowing what should be done can kill. Just study a competent electricians information on charging points for EVs and you will find out that doing it wrong can give you a car that is live at 220v~250v. Trying to open the car door could be a terminally exciting experience, but on the benifit side it would reduce your lifetime green footprint, wouldn’t it? ????

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