16A CEE would be enough in terms of overcurrent protection as long as the subsequent wiring is at least 1.5mm2 and the equipment itself is limiting the current. Basically: you can install a 5x1.5mm2 cord with 3ph plug and permanently wire 3 16A Belgian sockets on the cart, one of which is unused (or only use two phases). Or provide 2 10A IEC connectors and have the customer get two computer cords + regular extension cords.
