Okay, I'm not really into electric stuff - so bear with me.

Today I found out, why my electric fuel pump stopped working, the minus cable slipped out of the connection, so I put it back on a new eyelet and reconnected it (basically a screw in the sheet metal).
While doing this (mind you, the ignition and everything was off) I saw some sparks.
As far as I know, one should'nt see sparks coming out of a minus cable - right?

So I disconnected the minus cable from the battery, and measured between the minus pole and the loose cable.
Low and behold - I saw 12V on my multi meter.

Maybe I'm just dumb, but IMHO - with everything turned off - I shouldn't see any voltage there, or am I missing something?

Thanks Frank