What is the live and neutral wire from a "1" and "2"?

Hmm. I know that in the United States (don't know where you're from) on a receptacle there is a shorter slot and a longer one, (so plugs are inserted correctly).

The short slot is on the right and is 'hot'

The longer one is on the left and is 'neutral'

This also means that the prongs are different sizes. You might be able to tell that way using a continuity meter.

From the looks of the socket, though, my guess would be the center connection would be 'hot' and the outer connection 'neutral'. But that's just a guess.

 

As far as I know there is no polarity on the two power leads. The middle one is PE (yellow/green)(Protective Earth)
The reason for nonpolarity is that these connectors(IEC C13/C14) are normally used together with a Schuko plugg, that is nonpolarized in most countries.

 

Hmm. Interesting. I thought it was polarized because of the plug shape in picture 1.

It looks like it was made to fit in only one way. I might be wrong about this, just an observation.

 

An easy way to find out is to measure resistance (or continuity) between the earth wire and each of the other 2. In order for it to work the other end of the lead has to be plugged into the device. The earth should be connected to the neutral via the case (this method ensures that if the case becomes 'live' then it forms a short which will blow the fuse, while also making sure that the case is at the same ground potential as everything else).

 

Hopefully this is not the case, if you are outside UK there's a 50% chance to get it 'wrong' if the mains plugg is not polarized.

 

Dam - how do you all protect yourselves then?