checking for proper earth grounding of wall outlets

[jc_lim3]

Hello! do you have any ideas on how to know whether your wall plugs are properly earth grounded considering they are already three prong outlets?

[ante]

I don’t know where you live or what colors you have on your wires so it’s hard to guide you!

[jc_lim3]

My wall outlet is NEMA 5-15 / CS22.2 type or type B (american 3 pin). hope this helps!

[ante]

Well, this does not reveal the colors of your wires. Where I live we have earth (ground) wire green/yellow and neutral blue; these are connected in the service junction box (hot (phase) is black or brown). If I measure the voltage between the blue and the green/yellow wires it must be zero volts, if not there is a problem.

[Theatronics]

when it comes to line voltage in outlets I use a 'wiggy'
that’s a brand name, I am sure there are other names for it.

Electricians wouldn't be caught dead without one, In fact
Without one, they might just get caught--- dead.

A Multi Meter has a input resistance of about 20M ohms.

This is great for low voltage but for home wiring it can lie to you.

A WIGGY or similar device has a large AC electromagnet in it.
When you place the WIGGY on a circuit (Like a multi meter.)
the power from the mains causes the magnet to pull a little
marker down to the line voltage it is detecting.

(110,220,440 ect)

The resistance of a Wiggy is about 200ohms this means that
little stray voltages will not effect the reading.

When doing a test of your grounds, Use both a high Ohm device
like a multi meter and a low ohm device like a Wiggy to look for
problems.

If the Wiggy shows no voltage between 2 connections then
it is safe to say that to CURRENT exists there, but in sensitive
electronics that need a good 0V ground on a high impedance
circuit there may still be some VOLTAGE on the line due to resistance in the ground wire and a ground fault further up the circuit.



 

[ante]

Yes we have that kind too but,…. that’s cheating!  ;D
http://www.elfa.se/elfa-bin/dyndok.pl?lang=en&dok=2021555.htm?_76_458_64

[MP]

Hello! do you have any ideas on how to know whether your wall plugs are properly earth grounded considering they are already three prong outlets?

There will be no voltage between the third prong (Uninsulated or Green wire) and the return (White Wire). Also, you should have full potential between the Hot (Black Wire) to Return (White Wire) and also see full potential between the Hot (Black Wire) and the Ground (Green or uninsulated Wire). This should be the same potential. You should also see no potential difference between the wall plate screw and Return or Ground. This tells you that the receptacle box is also grounded. The Return and Ground follow separate paths in the wiring, but are connected at the power box where the ground will save you if you have an open in the Return. (Provided that the appliance is setup for this protection).
Hope that helps. To insure the ground is always working, you can install a GFCI type receptacle, which will open up the circuit in the event that the ground is not good.

MP