In uk.d-i-y, Owain wrote:

I've never really understood what RCD actually means. I know what they do
and how to use them, but Earth Leakage Circuit Breaker does exactly what it
says on the BS EN IP-rated enclosure.

I guess inbetween Esther Rantzen on the one hand, and the nomenclature
police at IEE ("extraneous-exposed-conductive-part" - I ask you!) they
came up with this neutral no-name thang. "Differential" rather than
"residual" might've been a little clearer. "Current Balance Device"
would've been informative, *and* used shorter words. Ah well... no-one
asked me, right? ;-)

Stefek