It's very trendy to mock "Health and Safety Gone mad." Ignore all that, protect yourself and others... there's nothing big or clever about a work or DIY related injury and as the zombie apocalypse hasn't happened at the time of writing these gizmos are still a shrewd move.
Older gear uses something called an Earth Leakage Trip (ELT) or Device (ELD).
Newer gear uses a better system called a Residual Current Device (RCD), residual-current circuit breaker (RCCB), or ground-fault circuit interrupter (GFCI).
