Earth continuity ?

[Martin Page]

How does one detect that an earth wire in a plug is in fact earthed.

The Bedroom plugs in my casa are all two pin, no earth, I have run an earth round the circuit but can not get back to the distribution box. to pick up a known Earth (That I have retro fitted)

I have a 3.5mmm brown wire that I think is part of the original Earth. It doesnt help when all the wires are black brown and grey. In the main the Grey is line and the Brown Neutral ( The black 1.5mm is for the live on the lights) but I have come across brown line and gery neutral just to keep me on my toes!

The 3.5mmm brown is not positive or negative since it wont make a circuit but how can I test it for continuity to earth.

Or .. is it safer to retro fit a second known earth pole (only some 10 mt from the distribution Box )

[gerryh]

How does one detect that an earth wire in a plug is in fact earthed.

The Bedroom plugs in my casa are all two pin, no earth,


The 3.5mmm brown is not positive or negative since it wont make a circuit but how can I test it for continuity to earth.

I assume you mean bedroom sockets?
To test for continuity you need a continuity tester, the resistance setting on a multimeter.
Connect one end to the brown wire and the other end to a known good earth. If there isn't any resistance measured then the brown wire is connected to earth.
Advice doing this with the mains switched off in case the brown wire is connected to something else.
Cheers
Gerry

[Conehead]

Quote
If there isn't any resistance measured then the brown wire is connected to earth.

Unquote

I think you mean:-
If there isn't any resistance measured then the brown wire is NOT connected to earth.

In theory there should also be a low resistance been ground and neutral, but this is Spain!

[knowal]

Quote
I think you mean:-
If there isn't any resistance measured then the brown wire is NOT connected to earth.

In theory there should also be a low resistance been ground and neutral, but this is Spain!

I think he means:
If there isn't any resistance measured then the brown wire IS connected to earth.
i.e. 0 Ohms

Conehead, it's best not to post about electricity unless you know something about it. Someone could get hurt following poor advice.

[gerryh]

Quote
If there isn't any resistance measured then the brown wire is connected to earth.

Unquote

I think you mean:-
If there isn't any resistance measured then the brown wire is NOT connected to earth.

In theory there should also be a low resistance been ground and neutral, but this is Spain!

No, if there isn't any resistance, i.e zero resistance then it is connected to earth.
If it has a high or infinitive resistance then it isn't connected to earth.
Don't forget i said to measure the resistance between the cable and a known good earth point.
Cheers
Gerry

[Conehead]

White Horse
Quote
Conehead, it's best not to post about electricity unless you know something about it. Someone could get hurt following poor advice.
Unquote

I have been involved with "electricity" probably before you were a twinkle in your father eye and I am now over retirement age and still commissioning in various overseas countries. I designed digital control systems for what was then the largest elctrical company in the UK so I think I know a bit about electricity and how things are in some countries. The origianl poster had a problem, a good response wasa made but, to me, the wording of the reply was ambigious.

When I read "there is not any restance measured" I thought, obviously wrongly, that the reading was open circuit. A reading of zero resistance is still a resistance.

As I have now left Spain for good I will make no further commects about this or any other subject.

[frank]

I have been involved with "electricity" probably before you were a twinkle in your father eye and I am now over retirement age and still commissioning in various overseas countries. I designed digital control systems for what was then the largest elctrical company in the UK so I think I know a bit about electricity and how things are in some countries.

Touché, José! Good answer!

[julian]

maybe if this question had been posted in an electrical problems forum instead of a forum about andalucia there would be less confusion.

[knowal]

White Horse
Quote
Conehead, it's best not to post about electricity unless you know something about it. Someone could get hurt following poor advice.
Unquote

I have been involved with "electricity" probably before you were a twinkle in your father eye and I am now over retirement age and still commissioning in various overseas countries. I designed digital control systems for what was then the largest elctrical company in the UK so I think I know a bit about electricity and how things are in some countries. The origianl poster had a problem, a good response wasa made but, to me, the wording of the reply was ambigious.

When I read "there is not any restance measured" I thought, obviously wrongly, that the reading was open circuit. A reading of zero resistance is still a resistance.

As I have now left Spain for good I will make no further commects about this or any other subject.

OK, fine, as long as you realise that you were wrong.
Whether you ever post here again is of no matter to me, as I have no problem with you personally. However if you post dangerous rubbish about electricity, do expect to be challenged.
Have a nice day, and don't take it so personally. It's only a forum.

[Martin Page]

Well .. that was usefull ...

If Check the unknown 3.5mm Brown to MY known earth there is no continuity. however That doesnt preclude that it may be earthed to the Original earth.

If I take a DC voltage reading from a computer case screw head to the grout between the tiles I get a 0.25- 0.5v when the plugs are connected to a temporary new earth.
When the plug earths are conected to the 3.5mm brown the voltage is unreadable varing from 0.7-1.95v

If I disconect the earth from the plugs, there is enough voltage in the computer case to feel it on my wrist when im not insulated. .. the reason to connnect the earth

Have I read some where that you must not have earth rods too close to each other fo some reason and is 10m too close

[knowal]

If I were you, I would trace the wire back to the junction box and see if it is connected inside the junction box.
When I did some work on my kitchen last year I found 2 brown wires with an earth in the wall. They were running back to the junction box, but were not connected in. I used these to feed a new kitchen socket.
Report back soon!

Just as an aside, the lack of respect for colour standards in house wiring in Spain, even in new houses is really irresponsible. Another problem is the habit of putting the light switch in the neutral line, leaving the lamp holder (or wires) live when the light is switched off.

[gerryh]

Martin
Why are you measuring DC voltages?
I assume your house supply is AC.
How are you checking for continuity?
Cheers
Gerry

[Martin Page]

Would that I could trace it back any further than where I am now ... there is no other apparent conection to it .... hence the question ?

[Martin Page]

Gerry - continuty is measured by resistance in Ohms - 0= Ohms cotinuity -Blank= Open circuit else other actual resistance.

...and yes - 240v single phase mains supply

Because the computer electrics at 12 v or 3.5v DC .. I get a steady reading on the 2v DC scale