The 5UB1938 is the aluminum metallic DELTA i-system socket with center protective contact — a Type E (CEE 7/5) socket, not a German Schuko. It is the silver-toned counterpart to the carbon metallic 5UB1928, built for installations in France, Belgium, Poland, the Czech Republic, Slovakia, and parts of North Africa where Type E is the national wiring standard.

Is this a standard German Schuko socket?

No. German Schuko (Type F, CEE 7/3) uses two side-mounted spring clips for earthing. The 5UB1938 is a Type E (CEE 7/5) socket: earthing is provided by a protruding metal pin in the center of the socket face that mates with a recessed contact on the plug. Physically inserting a pure CEE 7/4 Schuko plug (no center hole) into a Type E socket is impossible — the center earth pin blocks it. CEE 7/7 hybrid plugs — the universal European plug found on most modern appliances — have both the side earth contacts and a center hole, so they work in both Type E and Type F sockets. If your installation uses French-standard plugs (CEE 7/6, with a center earth recess), you must use a Type E socket — a German Schuko will not provide an earth path for those plugs.

What is the safety advantage of the center earth pin?

The protruding earth pin on a Type E socket is longer than the live and neutral contacts. When a plug is inserted, the earth pin mates first; when the plug is withdrawn, the earth pin disconnects last. This first-make-last-break behavior ensures the appliance chassis is grounded before the live circuit is completed and remains grounded until the live circuit is fully broken. On a Schuko socket, the side earth clips and the live pins engage roughly simultaneously — there is no guaranteed earth-first sequence. For fault scenarios where the plug is pulled while the appliance has an insulation failure, the Type E design provides a measurable safety margin.

How does the 5UB1938 differ from the 5UB1928?

The two are functionally identical — both are Type E CEE 7/5 sockets with increased touch protection, screwless terminals, 10/16A 250V rating, and IP20 protection. The only difference is the finish: 5UB1938 is aluminum metallic (~RAL 9006, 88g), while 5UB1928 is carbon metallic (~RAL 7016, 85g — though Batch 9 data did not record a weight for 5UB1928, the carbon-aluminum weight difference is typical). Choose the finish that matches your DELTA i-system frame installation.