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Earth leak on outside Aircon unit


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rizla

So last weekend I brushed against the wall support of my outside aircon unit, and received an electric shock, I was in bare feet.

Called out the installers, who came today, after several hours they decided to wire a ground wire to the internal unit nd the house ground, problem solved, except in my mind I cannot see this as a solution, when they measured the original ground point, on the external unit without a ground cable, it read over 100Vac. So by actually grounding the unit this means the 100vac is leaking to ground 24 hours a day 365 days a year. I cannot for life of me, understand how this is a good solution, surely they need to find where the leakage is occurring and fix that? Or am I missing something?

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Woolf

You are in Argao, so I guess that your electricity is supplied by one the Cebeco companies

you have 220/240 hot and a neutral

the is probably a  EMI filter in your unit

At the drawing below you will see 2 capacitors Cy

they are like a voltage divider so at the center point will be half the voltage so if center point is not grounded you will measure  half the line voltage (110/120) with a high impedance meter

the current is very very low will not even trigger a ground fault relay 

It will not kill you

It is normal

emi filter.png

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Woolf

Here is explanation in german, I have not been able to find good explanation in english

use google translate if you do not understand german

https://de.wikipedia.org/wiki/Netzfilter

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RogerDat

I do not walk IN my house barefooted much less outside barefooted, the germs here on the ground are a killer for diabetic people, and I do not touch any switch, electrical appliance unless I have my shoes on dry feet.

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rizla
2 hours ago, Woolf said:

Here is explanation in german, I have not been able to find good explanation in english

use google translate if you do not understand german

https://de.wikipedia.org/wiki/Netzfilter

Thanks for the info, interesting.

From the subdivision maintenance engineer, he told me live and neutral are both hot, which I understand, the point I was trying to make is that if there is a constant leak of around 110v, by earthing that it means that current will be leaking directly to earth 24 hours a day and I will pay for that.

 

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rizla

 

Update, this afternoon I switched on both my air cons and within 5 mins lost all power, some hours later I was told my meter had blown due to exceeding 100amps. The engineer said he will upgrade to 150 amps, but 

Two inverter aircons, a small fridge and two phone chargers drawing 100 amps is crazy.

I believe there is a fault with the aircon unit and that is causing a massive drain on the power, possibly due to the guys wiring an earth that was not required. But proving this is going to be fun!

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Woolf
26 minutes ago, rizla said:

Thanks for the info, interesting.

From the subdivision maintenance engineer, he told me live and neutral are both hot, which I understand, the point I was trying to make is that if there is a constant leak of around 110v, by earthing that it means that current will be leaking directly to earth 24 hours a day and I will pay for that.

 

you are in a cebeco supply area, you have 1 hot and one neutral that is grounded at the pole transformer

there is NOT 2 hots

Check drawings below

The very very low leakage current is normal, it is so low that I think it will not even turn the meter

you have it in usa also, but you may never have found out as most equipment there is grounded

with the 3 prong plug

pole trafo.jpg

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RogerDat

May I suggest that if the new meter has a amp meter like mine does, turn on only one item at a time, and see what the readings are. If everything is off, it should not be pulling any amps. AC units normally pull about 3 amps ( mine do), so I agree, something is wrong if it blows a meter, but does not trip a CB, or surge protector.

 

ALSO, normally the CASE is grounded, not the circuit as I understand you saying.

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Woolf

Found some description of emi/emc filters

https://product.tdk.com/en/products/emc/emc/power-line/technote/pdf/generaltec_power-line_en.pdf

Cy capacitors are typical 4700 pF, at 60 hertz impedance is aprox. 560 kohm, that is 0.000214 amp at 120 volt

or 0.05 watt or 0.00005 kWh

Quote

6) Leak current Leak current is the current leaking from power supply lines to cases (ground), when noise filters are inserted in power supply lines and a rated voltage is applied. This value is mainly dominated by electrostatic capacitance (C), power supply voltage (E), and power supply voltage frequency (f), and found in the expression below. Leak voltage = 2πfCE If this value is large and noise filters or ground terminals are ungrounded, electric shock can occur.

 

emc filters.png

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rizla
2 hours ago, RogerDat said:

May I suggest that if the new meter has a amp meter like mine does, turn on only one item at a time, and see what the readings are. If everything is off, it should not be pulling any amps. AC units normally pull about 3 amps ( mine do), so I agree, something is wrong if it blows a meter, but does not trip a CB, or surge protector.

 

ALSO, normally the CASE is grounded, not the circuit as I understand you saying.

I doubt a new meter will be installed before I leave for China, fly Friday!, but I will ask my housekeeper to take daily readings with and without the aircons on, I have asked to the newer digital meters as they have many useful readings I believe.

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RogerDat

I mean you should turn off all items, and as you turn on each equipment, see what it reads, then turn it off, and go to the next item until you find the drain.

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