I'm dreadfully sorry, I was too quick. safety plug ist der Schukostecker an sich... aber nicht die steckdose...

Would a "Steckdose" not be a socket?

Im Archiv gibt's dazu auch schon was
related discussion

shockproof wäre ja stoßfest.
Schutzkontakt bedeutet jedoch dass ein Erdepotentialkontakt vorhanden ist.

This is what we always used for literature pertaining to generators. Anybody who works with electrical equipment will understand this, since it's a very specific outlet type.

"Schuko" is a short form of the German term Schutzkontakt (literally: protective contact), which simply indicates that plug and socket are equipped with protective-earth contacts (in the form of clips rather than pins). Schuko connectors are normally used on circuits with 230 V, 50 Hz, for currents up to 16 A.

When inserted into the socket, the Schuko plug covers the socket cavity and establishes protective-earth connection through the earth clips before the live and neutral pins establish contact, thereby preventing users from touching connected pins. (Hence the Schuko system does not require partially insulated pins as used in the europlug and the British and Australian plugs.) A pair of non-conductive guiding notches on the left and right side provides extra stability, enabling the safe use of large and heavy plugs (e.g. with built-in transformers or timers).

Wikipedia!

So the most appropriate translation for Schutzkontaktsteckdose is probably something like appropriately earthed socket.

Why not simply call it safety socket?

I know that earthed is used at times but generally it is called a grounded socket.

Bei conrad UK einfach eine Schuko Steckdose suchen. Im Conrad Kattalog muss die Bezeichnung stimmen, da es sich um einen Fachhändler handelt.
http://www1.conrad-uk.com/