Bench multimeter calls for ground (which I do not have)

[xlzslayer]

I'm probably missing something? That IEC you show has earth connection. Two prongs and that metallic strip. The jack should have two holes and a couple of metalic contacts. This is where earth connection is made. Of course, it could be that the electrical installation in your building is defective or anything.

Yes, the plug is meant to be used on grounded outlets, we don't use them on grounded outlets. They fit, so it's what people use, that's really all there is to it, that's the standard here, pretty advanced right?


What I said above still applies as the standard in the country, but looking back at it, my home setup is quite a bit unique. It's been rigged where some outlets of a different color can be supported by a main UPS during power outages (The UPS is not currently present/in use), It's been rigged to support a generator powering everything in the apartment, and it's been rigged to support a first party and a third party power provider for when one goes out. The first party power provider is the government, which has been very inconsistent in the last few years. You also made me look again at my outlets since they're not the standard here, my father did the electrical installation around 10 years ago. The outlets do indeed have ground metal contacts, European style, but I always thought they were just dummies, not actually grounded.

I took some measurements. I do want to note that I'm currently on third party power. Live and Neautral measured ~231VAC, Live and Ground anywhere between ~75-85VAC measured at a few minutes apart, Neutral and Ground ~55VAC. So the ground is connected to something, but it's not earthed properly?

[bdunham7]

I took some measurements. I do want to note that I'm currently on third party power. Live and Neautral measured ~231VAC, Live and Ground anywhere between ~75-85VAC measured at a few minutes apart, Neutral and Ground ~55VAC. So the ground is connected to something, but it's not earthed properly?

You'll get odd results using a handheld DMM with 10M input impedance because you're measuring small amounts of leakage current.  This is why the LowZ function was introduced.  If you don't have LowZ on your meter, then try putting a 100K 1W resistor in parallel with the meter (very carefully, make something safe to connect all that) and see what your voltage looks like then.  Your measured voltages are entirely consistent with the possibility that the grounds are not connected to anything.  OTOH, it is also possilble that your third party power supply is not ground referenced.

[Xena E]

Be very careful xlz slayer.

I have experienced domestic instalations where outlets have had ground connections that were connected together but not to ground!

What you may be measuring is some artifact caused by something plugged into another outlet.

X

[xlzslayer]

You'll get odd results using a handheld DMM with 10M input impedance because you're measuring small amounts of leakage current.  This is why the LowZ function was introduced.  If you don't have LowZ on your meter, then try putting a 100K 1W resistor in parallel with the meter (very carefully, make something safe to connect all that) and see what your voltage looks like then.  Your measured voltages are entirely consistent with the possibility that the grounds are not connected to anything.  OTOH, it is also possilble that your third party power supply is not ground referenced.

Oh I see, yeah my handheld meters don't have that feature, however I just received the Fluke meter! I assume it should show better results since it has lower input impedance:
Live and Neutral measured 226VAC, Live and Ground 22VAC, Neutral and Ground 8VAC

Since the values are lower, I assume they're closer to the reality that the ground isn't connected to anything?

[bdunham7]

Since the values are lower, I assume they're closer to the reality that the ground isn't connected to anything?

Yes, that does seem to indicate that your "ground" is floating free, perhaps along with some leakage from other things around the house as Xena E suggested.

[tatel]

You also made me look again at my outlets since they're not the standard here, my father did the electrical installation around 10 years ago. The outlets do indeed have ground metal contacts, European style, but I always thought they were just dummies, not actually grounded.

Well to have these ground contacts connected all you need is to make another wire to pass trough the plastic tubes of the electrical installation. That way hopefully you can get to street level where a copper rod 20 mm diameter 2 meter long could be nailed into earth. Probably after drilling trough concrete. That's easily seen here on old buildings.

However we have here about 2000 mm rainfall/year so there is quite a bit of moisture in the soil. On a dry climate that earth connection could have too much resistance. Perhaps, if the building has the structure made of concrete, could you make the earth connection to the rebar inside the concrete?

AFAIK, to use a water pipe for earth connection is forbiden here.

I think any local electrician will know about the climate and all those exotic power sources you are compelled to use, therefore could give you the best advice abouth this matter.

[themadhippy]

That way hopefully you can get to street level where a copper rod 20 mm diameter 2 meter long could be nailed into earth

which will do nothing if the  electrical network isn't connected to mother earth,even an rcd/gfi is about as much use as a chocolate fireguard in such cases

[bdunham7]

which will do nothing if the  electrical network isn't connected to mother earth,even an rcd/gfi is about as much use as a chocolate fireguard in such cases

If the line and neutral are actually completely isolated then there's no (single touch) shock hazard in any case.  In reality, there will always be leakage from various devices.  A real ground will prevent the things attached to it from floating up from ground, the remaining hazard is if your location (where your feet, etc are) are not at the same ground potential. 

[Xena E]

*Beyond the issue of the multimeter*

Without a designated neutral tied to ground from whatever source of power that is being used, (inexpertly installed emergency generation is notorious for this), then installing an unconnected random earth could just be making the situation more dangerous.

It's sketchy.

If you have no control over it, be very wary.

X