I bought one of those non-contact voltage testers. It is made in China, of course.
It works well and made me laugh reading the instruction:
- Voltage test Display: if the tested voltage doesn't reach 70% of higher voltage, it will display lower voltage
- Can be used to clip glasses, business cards, tickets, etc
- Breakpoint test: Keep the tip of tester 1-5 cm from the tested electric line, if an induction marking is found on the LCD, the tested line is firewire.