Hi Cazzo
greetings .. also from Australia
Hello
I'm in Australia, so my mains is 240VAC 15A. It has 3 holes for the plug (but some appliances only use two of them)
My question is, what are these leads? I know the top two are power and the bottom is earth, or ground but what does this mean?
Is the top 2 "negative and positive" obviously its AC so its changing but thats where there is power. And i hear people calling these wires "live", "hot" whats does this all mean. - What are all the wires called, and where do they go.
Rather than Negative and Positive, which is really used in DC circuits not AC circuits.
The more correct terms are Neutral and Phase The phase wire is the HOT/LIVE wire calling them the HOT or LIVE are just laymans terms.
In Australia and some other countries, the neutral lead is connected to the earth line at the house/building fuse/meter box. The earth wire connects to a real earth, usually a metal rod hammered into the ground, beside/under the house and relatively close to the house. The earth line then spreads out to each power point and then out to the appliances where it will connect to the metal chassis (casing) of the appliance. If for some reason the phase ( hot) wire becomes disconnected inside the appliance and it touches the metal casing it will cause a large current to flow and blow the fuse on that circuit and protect you from getting a possibly lethal electric shock.
You will find some appliances have only 2 pin plugs, neutral and phase, The applicance is designed in a way that it should be pretty much impossible for the phase wire to come into contact with the metal case. You can also google a term called "double insulated" often used in conjunction with power tools
- And this originally lead me to this curiosity, the earth lead. there is NO power in there right? it is only earthing the appliance used yea? Why does the appliance need to be grounded. and i saw a guy connect a wrist band into this ground plug on his wall outlet, my first reaction was WTF you idiot!!!! but im not sure how it works.
Very simple question, hope you can help bro
What you saw the guy doing was connecting an anti static strap and lead to the earth wire at the power point. in that case, usually there would be a also be an antistatic mat on his work bench.
They are used to static voltage that builds up on your body/clothing whilst walking across carpets etc. If he was to touch sensitive electronic circuit boards without discharging through the antistatic strap, he could zap the electronics...... surely at some time you have walked across carpet somewhere and grabbed a door knob and got a zap ?
cheers
Dave