Irek.N. wrote:

> Z Twojego opisu odniosłem wrażenie, że nadrzędną cechą jest fakt
> niemożliwości połączenia styku NO i NC.

https://pl.mouser.com/datasheet/2/16/relacat-2307308
.pdf

Forced-Guided Contacts: Electro-mechanical relay
contacts that are mechanically linked together, so
that when the relay coil is energized or de-energized,
all of the linked contacts move together. If one set of
contacts in the relay becomes immobilized, no other
contact of the same relay will be able to move. An
open-contact gap > 0.5 mm ( 0.02 in.) is maintained
during life of the relay, even with malfunction, and at
1.6 x Nominal Voltage. Forced-Guided contacts are
also known as captive contacts, positive-guided
contacts, or locked contacts. They are used in
Safety Relays.

Pozdrawiam, Piotr