Here's a 10 (right) and 30 KV (left) concrete Pole near Billerbeck, the glass suspensions insulators are brand Sediver an the right side are 2 pairs of old brown ceramic insulators holding the wires, this insulators are used often in the past but are often replaced by the Sediver insulators.

The power company RWE use 2 Sediver discs for ten and 3 discs for 30 KV.

The German rail company 'DB' use glass suspensions insulators also for its 15 KV overhead power supply; they use normally 3 discs (at some location 4 discs).