I'm sure we've all come across those laymen who ask a question along the lines of "What's the highest voltage you can touch and still be safe?" We all know that there's no easy answer to that one.
On the definition of extra-low voltage, let's not forget that limits have risen over the years.
If we go back to the 14th edition of the IEE Regs. we find that extra-low voltage is defined as:
Normally not exceeding 50 volts between conductors, and not exceeding 30 volts a.c. or 50 volts d.c. between any conductor and earth.
So some supplies now considered to be extra-low voltage would have been classed as low voltage prior to 1981.
