1. The ratings on this switch illustrate the significant differences between ac and dc voltage ratings, for the same current rating. While there’s an enormous variety of switches available ...

Even at a low DC voltage, the arc across the switch contacts was dramatic, particularly upon break. With the voltage cranked up to the full 240-volts of the UK mains, [John]’s switch was ...

Yet, this is not the case with a DC circuit, where the voltage and current are constant. Once the power is switched off, it can take longer for the voltage arc inside the switch to extinguish itself.