Voltage difference ground to neutral

[Crossy]

I'd be tempted to pull those two whites from the ground bar and see if anything stops working (coz it's getting a return path via the ground).

 

In our old condo ALL the aircon was connected with the neutral feeds on the ground bar, supply was TN-S so it worked just fine until I wanted to install an RCBO.

 

[Jack 0009]

8 minutes ago, Crossy said:

You absolutely need a KNOWN reference, you cannot rely on ANYTHING in the box for now. Bang that big driver into the lawn and water it if it's a bit dry.

 

 

I did notice two white wires on the ground bus.

I am not an Electrician but a Electo-mechanical repairman. So in 42 years of work when I measured incoming power to my machines if ir wasn't right I had the customer get their electrician to rectify the problem.  So my experience is not as an Electrician. different skill set 

[Jack 0009]

Just now, Jack 0009 said:

I did notice two white wires on the ground bus.

I am not an Electrician but a Electo-mechanical repairman. So in 42 years of work when I measured incoming power to my machines if ir wasn't right I had the customer get their electrician to rectify the problem.  So my experience is not as an Electrician. different skill set 

I agree with you must know reference

[Crossy]

2 minutes ago, Jack 0009 said:

I did notice two white wires on the ground bus.

I am not an Electrician but a Electo-mechanical repairman. So in 42 years of work when I measured incoming power to my machines if ir wasn't right I had the customer get their electrician to rectify the problem.  So my experience is not as an Electrician. different skill set 

 

Still likely better than a Thai domestic sparks ???? 

 

Thailand has many very good electricians, but most of them are earning $$$ on the mega-projects or O&G.

[Jack 0009]

15 minutes ago, Crossy said:

I'd be tempted to pull those two whites from the ground bar and see if anything stops working (coz it's getting a return path via the ground).

 

In our old condo ALL the aircon was connected with the neutral feeds on the ground bar, supply was TN-S so it worked just fine until I wanted to install an RCBO.

 

another thing I did was measure between E and N then turn the individual breakers off one at a time.  generally had around 75 VAC but on one of the breakers that voltage dropped to around 50 VAC 

[bankruatsteve]

@Jack 0009 Are you measuring L-N from the screws on the main breaker?  And only 156V?  Something not right if so. 

[bankruatsteve]

Suggest you do this next time there:

1.  Off the main. Measure L-N. If not between 215-240V, call PEA.

2.  On the main breaker. Off all the MCBs. 

3.  One at a time, turn on MCB and check voltage at main.  If there is significant V drop, notate and off the MCB.  Continue and let us know results. 

[lopburi3]

2 hours ago, Crossy said:

I'd be tempted to pull those two whites from the ground bar and see if anything stops working (coz it's getting a return path via the ground).

 

In our old condo ALL the aircon was connected with the neutral feeds on the ground bar, supply was TN-S so it worked just fine until I wanted to install an RCBO.

 

Indeed it appears someone attached neutral wires to the ground bus at some point (probably did not see the 1/2/3 open slots on the neutral bar as above the "N").  Not sure where the Safe-t-cut is in system but if before panel a trip of that or main breaker should make panel safe to work on (but check everything with multimeter to be sure).  If these white lines are indeed neutrals something will stop working when detached and they can be attached to the neutral bar where they should be. (power off again of course).

[Jack 0009]

2 hours ago, bankruatsteve said:

@Jack 0009 Are you measuring L-N from the screws on the main breaker?  And only 156V?  Something not right if so. 

L from the main breaker N from the bus

[bankruatsteve]

10 hours ago, Jack 0009 said:

L from the main breaker N from the bus

I would go from the screws on the main breaker for both.  That way you are getting mains voltage regardless of breaker state. 

[Crossy]

OK - Do this.

 

You are still going to need that big screwdriver - let's call that Ref.

 

Main breaker OFF.

Measure (expected result):-

Incoming L - Incoming N (220V)

Incoming L - Ref (220V)

Incoming N - Ref (OV ish)

Incoming L - E (220V)

Incoming N - E (OV ish)

 

Repeat with main breaker on but all other breakers OFF - should be the same.

 

If all is well, turn on one breaker which you can apply a decent load with, say the kitchen outlets and the oven/kettle/toaster.

Make the same measurements, results should be roughly the same.

 

If they are NOT report back with the numbers. 

 

Continue turning on breakers until something different happens.

 

If you get significantly different measurements to Ref. with a load on, try similar checks at the meter (identify if it's a PEA or household problem).

 

[PMK]

I'm going to find someone else to hook up the ground and will post back when that is done. Thank you all very much.

[bankruatsteve]

With main breaker off, I would move those 2 (apparent neutral wires) from the ground bar to the neutral bar first.  That might be your issue.

[Crossy]

1 hour ago, bankruatsteve said:

With main breaker off, I would move those 2 (apparent neutral wires) from the ground bar to the neutral bar first.  That might be your issue.

 

Whilst it's not likely to introduce a hazard I'd really like to know what they are first. 

 

Disconnect them and see if anything stops working would be my first move.

 

[86Tiger]

36 minutes ago, Crossy said:

 

Whilst it's not likely to introduce a hazard I'd really like to know what they are first. 

 

Disconnect them and see if anything stops working would be my first move.

 

 

 

More importantly, check if the 75V between N - G goes away.

[Crossy]

9 minutes ago, 86Tiger said:

More importantly, check if the 75V between N - G goes away.

 

I've already set out in earlier posts what I would do to diagnose the issue based upon what our OP is reporting (tingles from earthed kit and an apparent 75V N-E). 

 

If our OP wishes to randomly add bits to his installation without actually diagnosing the issue it's entirely up to him.

 

Horses, water etc.

 

I still suspect a floating ground but ...

[KhaoYai]

On 3/28/2021 at 9:19 AM, Crossy said:

Is that ground actually connected to the ground at the box and then the rod? A LOT of extension leads hve 3-pin plugs and outlets with 2 core cable!

Yes and a lot of circuits have earths that go to the earth bar in the consumer unit and no further ????.

[daveAustin]

Likely unsound earth/awry neutral, though both of which would trigger rcd. As an aside, if you run a washing machine it'll induce emf on spin and bung it everywhere if no solid earth. Sorry, bruv, but your wiring sucks. ????

[elliss]

On 3/28/2021 at 3:21 PM, PMK said:

OK. I will do my own ground. I actually started to do that but backed off because of the other opinion.  I'm familiar with the ungrounded 3 pin extensions in Thailand. ????

 

 

 Do a PH , test on your soil . 

   Conductivity varies ,  on soils PH ..

    

[elliss]

On 4/2/2021 at 6:07 AM, daveAustin said:

Likely unsound earth/awry neutral, though both of which would trigger rcd. As an aside, if you run a washing machine it'll induce emf on spin and bung it everywhere if no solid earth. Sorry, bruv, but your wiring sucks. ????

 

 Electro Motive Force .

  Ah, those were the days ..555

   

[elliss]

On 3/31/2021 at 1:41 AM, KhaoYai said:

Yes and a lot of circuits have earths that go to the earth bar in the consumer unit and no further ????.

 

  RIP ..

[Jack 0009]

On 3/30/2021 at 5:04 PM, Crossy said:

 

I've already set out in earlier posts what I would do to diagnose the issue based upon what our OP is reporting (tingles from earthed kit and an apparent 75V N-E). 

 

If our OP wishes to randomly add bits to his installation without actually diagnosing the issue it's entirely up to him.

 

Horses, water etc.

 

I still suspect a floating ground but ...

You are correct sir it was a floating ground. I went over to his house today and he hooked up a temporary ground. the voltages measured at nominal voltages and no more getting shocked of his Guitar. 50Hz hum on his amp is gone as well

[Crossy]

Job's a good 'un ????

 

[xylophone]

On 4/3/2021 at 7:36 PM, elliss said:

 

 Electro Motive Force .

  Ah, those were the days ..555

   

Ah, takes me back to my Technical College days in the 60s in the UK. Haven't heard that term for ages.

[PMK]

Finally got a least a good temporary ground installed. No shocks, no weird noises from my guitar amp anymore. Less than 1 volt diff between earth and neutral now. I have an "electrician" - don't know yet if he deserves the title, coming up soon to run a proper new ground and give an opinion/explanation on those white wires going to the ground bus.  I'm not inclined to move them just to see what happens. ????