Do's and don'ts in home lab with no earth ground

[mag_therm]

Is that the old type E France plug?
More basically,initially,
I would get a 100 kOhm 1 ~ 5 Watt Resistor:
(220 ^2) /100000 =0.48 Watt

Connect across the pins of an old , spare plug.
Now you can check with a multimeter, which side is lowest voltage and which side is "hot" to ground.
That is assuming you know how to do it safely, and there is a ground like embedded water pipe, steam heater pipe etc.

With old Test Equipment, Radios , other appliances,
 the first thing is to check that the On/Off switch and appliance fuse (if fitted)  is on the "hot" side.
With newer equipment I presume somebody already connected the outdated plug? So you can open it and check tightness and no splayed strands. And how is the ground wire terminated.
 
The ground test will also tell if there is residual voltage on the side that is supposed to be at ground potential.

[BillyO]

here that is a requirement is all residential installations no matter how old

Interesting.  If this is the case, then there must be access to ground for them to work.  Since you and the OP are form the same country... it follows he does too.

@bottledwater, do you have access to the basement?  Back when I was a kid and lived in a basement apartment I also did not have access to the ground outside, however, it was easy enough to drill a hole through the concrete in the basement floor and pound a rod in there (with the landlady's permission in my case).

[JustMeHere]

If you're really worried, put a GFCI breaker in your panel.

and if the incoming supply is not referenced to ground?

This was how I had my.old house.  The panel was grounded.  The bathrooms and kitchen were grounded.  We didn't rewire anything else.  Just dropped in some GCFI breakers.    It passed.code.  it worked. 

It might have worked too well.  A close lightning strike would pop about half the panel.  If probably did save my house when it flooded though.

[themadhippy]

This was how I had my.old house.  The panel was grounded. 

so the installation had a reference to ground,if the supply has no connection,or  a high impedance path to ground then your rcd aint gonna work

[bdunham7]

Interesting.  If this is the case, then there must be access to ground for them to work.  Since you and the OP are form the same country... it follows he does too.

This was how I had my.old house.  The panel was grounded. 

so the installation had a reference to ground,if the supply has no connection,or  a high impedance path to ground then your rcd aint gonna work

An RCD/GFI does not require a ground to operate.  There may be some models that will not cooperate and others that are labelled to indicate that they are intended to be used only with ground connections, but there are many that don't and there's no reason that their basic principle of operation would require a ground.  Do service panel RCDs have a ground wire in the UK or Denmark?

[langwadt]

here that is a requirement is all residential installations no matter how old

Interesting.  If this is the case, then there must be access to ground for them to work.  Since you and the OP are form the same country... it follows he does too.

it doesn't need an earth (ground) it triggers on a difference in phase and neutral current

[bottledwater]

@bottledwater, do you have access to the basement?  Back when I was a kid and lived in a basement apartment I also did not have access to the ground outside, however, it was easy enough to drill a hole through the concrete in the basement floor and pound a rod in there (with the landlady's permission in my case).

This was my first idea, but there's a concern that we'll hit ground water and get water coming up into the basement. I think the risk is low but I can't really accept any risk in that direction.

An RCD/GFI does not require a ground to operate.  There may be some models that will not cooperate and others that are labelled to indicate that they are intended to be used only with ground connections, but there are many that don't and there's no reason that their basic principle of operation would require a ground.  Do service panel RCDs have a ground wire in the UK or Denmark?

It doesn't have/need a ground wire. It probably works the way @langwadt explains.

[bottledwater]

Hi again, thanks again. Have been ruminating over this for a long time, so it's very nice to get some other eyes on it.

I drew up the way I understand what you're saying so far. Please comment.

[paulca]

To answer your original question.  What would I do?

I'd move  house.

[themadhippy]

An RCD/GFI does not require a ground to operate

Its doesn't need a ground wire,but the supply feeding it needs to have a reference to ground.

it doesn't need an earth (ground) it triggers on a difference in phase and neutral current

and where's that difference  going to go to complete the circuit if there's no earth?
Why dont rcds work on isolation transformers? and whats the difference between an isolation transformer and an incoming supply that has no connection to earth?

[bottledwater]

An RCD/GFI does not require a ground to operate

Its doesn't need a ground wire,but the supply feeding it needs to have a reference to ground.

it doesn't need an earth (ground) it triggers on a difference in phase and neutral current

and where's that difference  going to go to complete the circuit if there's no earth?
Why dont rcds work on isolation transformers? and whats the difference between an isolation transformer and an incoming supply that has no connection to earth?

Found the data on the model I have, if you're interested: https://support.industry.siemens.com/cs/pd/472574?pdti=pi&dl=en&lc=en-DK

[Doctorandus_P]

There is no absolute "earth". It is just a convenient convention.

Current always flows in loops, and Voltages are always differential measurements between two points.

As a result, if you have no "real earth" you can just simply create your own.
Just feed all your electronic equipment from the same extension cord, and use an extension cord which does have "earthed" sockets, even if the earth on the other side of the extension cord is not connected to anything.

Then also connect your ESD mat to the "earth" connection of your extension cord.
If you want to go real fancy, you can scrape the wallpaper off your walls put aluminium foil on it (also connected to your self created earth) and then put the wallpaper back. Now you have created a local faraday cage and anything outside it is then pretty much irrelevant.
If you then also connect the metal doorknob to your ESD mat, you will (dis) charge yourself to the same level as your "local earth" when you enter the room.

You can also have a look at how a RF measurement test setup is created with a LISN. (Line Impedance Stabilisation Network) It's mainly a fancy mains filter, combined with big steel plate that represents the local "earth" for RF measurement purposes. A "real" LISN is pretty expensive. Reason is probably that it is a relatively rare piece of test equipment and that its used for certification purposes, which demands close tolerances. Diy-ing a "usable" device is a lot easier, but you don't even have to do that. Just read a bit about the theory behind it and how it's supposed to be used.

[Terry Bites]

Have your landlord sued for reckless endangerment and for failing to comply with HD 60364?
So are neither side of your incomming mains supply earth referenced?

[langwadt]

Have your landlord sued for reckless endangerment and for failing to comply with HD 60364?
So are neither side of your incomming mains supply earth referenced?

The supply is earthed somewhere, but afaik houses build before 1975 do not require an earth connection and
outlets from before 1994 do not require earth, but a GFI is required in all installations

[paulca]

If you have no earth you have no G for a F to be I'ed

Yes, I know it will detect other leakage, but without an Earth there be no leakage.  Our friend will be the full current path and no GFI or he wont.

[langwadt]

If you have no earth you have no G for a F to be I'ed

Yes, I know it will detect other leakage, but without an Earth there be no leakage.  Our friend will be the full current path and no GFI or he wont.

the supply is earthed at the transformer/powerstation, the house doesn't need an earth for a GFI to work.

and if the supply isn't earthed somewhere a GFI will not work no matter what because the only current path is like a normal load that won't trigger a GFI

[bottledwater]

So are neither side of your incomming mains supply earth referenced?

I believe Neutral is earth referenced at the power distribution center. Old houses are not required to have a local earth but if you renovate you're required to make one. I'm just in a situation where it appears impossible to make a local earth.

If you have no earth you have no G for a F to be I'ed

Yes, I know it will detect other leakage, but without an Earth there be no leakage.  Our friend will be the full current path and no GFI or he wont.

the supply is earthed at the transformer/powerstation, the house doesn't need an earth for a GFI to work.

I think both statements are true: The RCD works without a ground because it detects if what goes in comes back out. If there's a difference, there's a leakage current going through me to earth instead of straight to earth.

This is the explanation on wiki [https://en.wikipedia.org/wiki/Residual-current_device]:

RCDs operate by measuring the current balance between two conductors using a differential current transformer. This measures the difference between current flowing through the live conductor and that returning through the neutral conductor. If these do not sum to zero, there is a leakage of current to somewhere else (to earth/ground or to another circuit), and the device will open its contacts. Operation does not require a fault current to return through the earth wire in the installation; the trip will operate just as well if the return path is through plumbing, contact with the ground or any other current path. Automatic disconnection and a measure of shock protection is therefore still provided even if the earth wiring of the installation is damaged or incomplete.

[BillyO]

An RCD/GFI does not require a ground to operate.  There may be some models that will not cooperate and others that are labelled to indicate that they are intended to be used only with ground connections, but there are many that don't and there's no reason that their basic principle of operation would require a ground.  Do service panel RCDs have a ground wire in the UK or Denmark?

Well, I do know how they are activated.  What I mean is, if there is no ground/earth for current to flow into, thus causing the current difference between the two power lines, then they would never trip.  In essence, they need a ground to work (or other connection where current can flow out of the circuit).  There would be no point in installing them if there was no ground anywhere in sight.  So, likely there is a ground coming into the building.  Possibly terminated at the entry panel?

Of course, they could just be requiring installation of them everywhere regardless whether or not they will ever offer any protection.  You know, like a screen door on a submarine.  It sounds like the sort of thing a government would ask for.

[TimFox]

An RCD/GFI does not require a ground to operate.  There may be some models that will not cooperate and others that are labelled to indicate that they are intended to be used only with ground connections, but there are many that don't and there's no reason that their basic principle of operation would require a ground.  Do service panel RCDs have a ground wire in the UK or Denmark?

Well, I d know how they are activated.  What I mean is, if there is no ground/earth for current to flow into, thus causing the current difference between the two power lines, then they would never trip.  In essence, they need a ground to work (or other connection where current can flow out of the circuit).  There would be no point in installing them if there was no ground anywhere in sight.  So, likely there is a ground coming into the building.  Possibly terminated at the entry panel?

Of course, they could just be requiring installation of them everywhere regardless whether or not they will ever offer any protection.  You know, like a screen door on a submarine.  It sounds like the sort of thing a government would ask for.

If there is no local ground connection in the building, but if you take an electrical appliance and drop it into a bathtub with water in it, some current will flow from the line through the water back to the ground connection at the substation, thus giving an imbalance that will trip the RCD.

[bottledwater]

Just feed all your electronic equipment from the same extension cord, and use an extension cord which does have "earthed" sockets, even if the earth on the other side of the extension cord is not connected to anything.

Then also connect your ESD mat to the "earth" connection of your extension cord.

This is exactly my plan so far. My remaining questions are:

1) What are the risks to me and my gear if I connect myself and its (chassis) ground connections through an ESD mat?
As far as I understand, this may bring me to half the line voltage due to the caps in the power supplies, so if I touch anything that's actually earthed, I could be in trouble. There was also a comment that the fuses on my gear won't protect it if there's no real earth connected.

2) Should I create an unconventional earth connection by connecting to a metal pipe?
Here, the suggestion is to at least put a current-limiting resistor in between. But I could also be charging pipes going elsewhere in the building.

If you want to go real fancy, you can scrape the wallpaper off your walls put aluminium foil on it (also connected to your self created earth) and then put the wallpaper back. Now you have created a local faraday cage and anything outside it is then pretty much irrelevant.

I love the idea of living inside a Faraday cage. This should alleviate any spiritual grounding issues 

[BillyO]

If there is no local ground connection in the building, but if you take an electrical appliance and drop it into a bathtub with water in it, some current will flow from the line through the water back to the ground connection at the substation, thus giving an imbalance that will trip the RCD.

If he has metal drain plumbing, as would be the case here, then he has a really good earth ground.  He could use that.

My bathtubs are plumbed with plastic on both the supply and drain.  If you drop a toaster into it, you better hope you are not in there.  RCD/GFI or not.   

[BillyO]

2) Should I create an unconventional earth connection by connecting to a metal pipe?

If you have metal drain pipes, they will make pretty good earth grounds.  Copper supply pipes can be good, but if you don't have access to a real earth it may not be possible to test them properly.

[TimFox]

If there is no local ground connection in the building, but if you take an electrical appliance and drop it into a bathtub with water in it, some current will flow from the line through the water back to the ground connection at the substation, thus giving an imbalance that will trip the RCD.

If he has metal drain plumbing, as would be the case here, then he has a really good earth ground.  He could use that.

My bathtubs are plumbed with plastic on both the supply and drain.  If you drop a toaster into it, you better hope you are not in there.  RCD/GFI or not.   

My point was to what trips an RCD, which are quite sensitive to the imbalance in currents between L and N (low mA).
Unless your plumbing uses de-ionized water, there is a substantial conductivity through it, even in plastic pipes.
I would not trust plastic plumbing as a grounding method, however.
In the US, appliances such as hair dryers must contain a GFI to deal with archaic houses that lack GFI outlets in the bathroom.

[BillyO]

Unless your plumbing uses de-ionized water..

Not here.  I'm on a well.  The water is chuck full of mineral and metal ions.

I would not trust plastic plumbing as a grounding method, however.

No, for sure don't do that.

[themadhippy]

but if you take an electrical appliance and drop it into a bathtub with water in it, some current will flow from the line through the water back to the ground connection at the substation,

But will that current be enough to operate an rcd? If the bath is on a wooden floor and all the pipe work is plastic can you be certain the loop impedance is low enough for 30ma to flow without the potential rising above 50v to earth (uk rules)