ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades Trailing sockets or Extension cords for Belgium

Yes - they are simply industrial grade connectors. The system specifies a great number of variations for different voltages, frequencies and amperages. 63A and up even have a pilot contact to control a contactor switching off the load when the plug is pulled.

A few examples: purple is for low voltage (48V I think), yellow is 120V between conductors, blue is 230V, red 400V.