USB charger causing death

[vaughan]

So how come my RCD tripped when I touched the damaged wire: the plane is double-insulated and has no earth?

 

[Doovalacky]

You were probably standing on ground? Somehow it has to find a way back via alternative path.
30mA is a very small amount so it does not take much even bare concrete can have enough moisture in it to provide a path.
If you are in a shed for example the entire steel frame is bonded to the earthing system to reduce the earth resistance.

Without getting too involved the current in a circuit is always the same in active and neutral. You can put an amp-meter in before or after a device and will get essentially the same reading. The appliance resistance connected governs how high/low it "flows".
If a difference occurs the RCD trips as it assumes its going to earth.

In general use earth leakage and RCD are just different names for the same device.

 

[Scott No Mates]

A rcd isn't go to protect you from getting in between active and neutral.

Only active and earth.

Isn't the earth generally tied to the neutral in Oz (except in 3 phase)?

Hence rcd will not work between earth and neutral not active and neutral.

 

[jameso]

Neutral runs through the rcd being able to measure current in active and neutral. I could draw a schematic but its late. So ill try to attach a pic