Why are all of my appliances becoming energized when ground wire is excluded?

Question

I live in Australia, with three-prong 240v power supply including ground prong. I own a simple plug adapter that does not include the ground connection. As far as I'm aware, using any appliance with this plug removes the safety of the ground protection, but should not have any further effects on the appliance. Instead, if I use this adapter with any of my appliances (washing machine, air compressor, etc) the chassis of the appliance becomes energised. By this I mean that I get a strong shock if I touch the chassis. Also, my proximity voltage detector and neon testing screwdriver light up when touching the chassis. My multimeter detects 0.3v running through the chassis (by the suggested method of touching one probe to the chassis and holding the other probe in my hand) Just touching both probes to chassis and trying all settings on multimeter gives infinite "1" result.

What is going on here? How serious is this problem?

Notes: 1. Yes, this is a follow-up to a previous question asked. 2. Yes, I have booked an electrician to come out, but it is always good to investigate yourself so that I can make sure that the electrician addresses the problem correctly. Also, I want to know if it's even safe for me to be in my house and use my appliances in the meantime.

Answer 1

It is unlikely that the chassis is getting "energized" for multiple reasons. First of all, if it was grounded the breaker would trip. Secondly, the power draw of a washing machine would be very dangerous if you touched it. Also, the design of such devices is done to make such accidents rare, otherwise the manufacturers would be facing hundreds of lawsuits. That you see the same thing in multiple appliances makes it improbable that it is current leak. (What is the probability that ALL your appliances have a dangerous current leak? Negligible.)

If you are convinced there is a current leak, it is easy to test. Just touch one end of a voltmeter to the "energized" chassis and the other to a ground. If it reads 240 volts, its energized. According to another post the OP apparently did this test and it turned out negative, confirming there is no hot chassis here, it is static electricity.

The shock is probably due to static electricity. Both washing machines and air compressors will build up very strong static electricity charges due to rotary motion. If this is not discharged by a ground, static electricity will accumulate and charge up any metal on the device. You also see this same effect on cheap, ungrounded shop vac-type vacuum cleaners.

Answer 2

I assume you have a 3-phase system? The Ground wire pins Neutral to Ground potential. In a 3-phase system, if you leave out the ground, the Neutral "floats" and can take on substantial voltage levels, compared to Ground, depending on the load on the 2 other phases.

That's what you feel when you touch it. 60V or more is not an unusual reading for a floating Neutral.

Answer 3

What may be happening is capacitive and inductive coupling between the ground wire in the plug and the other conductors.

An AC electrical system has the current flowing one direction then the other. You know what else works that way, radio transmission, and microwaves. They work by imparting alternating magnetic fields on antennas, and burritos causing current which is either picked up the radio's tuner, or converted into heat in the burrito.
The same thing happens between the conductors in your washing machine.
As long as that is the only reason you are getting shocked it isn't that serious of a problem yet unless you have a heart condition ( or you have a very long cord ).
( This is similar to how those non-contact voltage detectors pick up the alternating field. )

You should definitely make sure that anything that has a provision for connecting to a grounding system is connected, as that will protect you from getting electrocuted should a wire inside of the device shorts out on the case of said device.

---

You may still find out that you read a few volts even after everything is grounded, this is to be expected as the ground wire is connected to neutral which is connected to the neutral of the main distribution network, which means that any imbalance anywhere in the system can pull the neutral away from zero volts in respect to the Earth ( You are capacitively coupled to the Earth ). There are so many things that can cause such an imbalance that it is almost guaranteed that there is some imbalance.

This imbalance should be low enough that you can't feel it when touching something that is grounded properly. If you can feel it then it is a problem outside of your control, and you should contact your power provider. ( Only do so after making sure that your house is properly grounded, unless you like talking to a brick wall. )

Answer 4

My best guess is that your hot and neutral are swapped in your outlet and that your adaptor connects it's ground "output" to the "neutral".