falexandru:
Are you sure it is not about 3 KW?I would simply run away as far as possible from a 3kV power supply.
I would also like to stress that Arduino is a learning platform. So, perhaps starting by measuring smaller electromagnetic fields (like the ones from the house power supply) may be a fun (and reasonably safe) way to learn.
Good point. 3kV is not for the beginner...though, I suspect it would be safer than the house power supply! I'm guessing that 3kV supply, as dangerous as it sounds, is far less capable of producing lethal currents as is the mains supply!
But, in fact, NEITHER should be toyed with!
And BTW: It's current that kills you, not voltage. If it were mere voltage that was lethal, then people would be dropping dead from a static electricity zap!