I got hold of a large Merlin Gerin Masterpact M16N1 circuit breaker, from 1997, from a low voltage distribution drawout system. In the video you get a inspection of the various parts of the breaker and I have some fun making it work and test it!
Some product series data and the full article with teardown and all pictures is found here:
The Masterpact M series circuit breaker is used to protect and control low voltage distribution systems. It can be installed in main LV switchboards (incoming units, main and secondary outgoers).
Nominal current: 800 to 6300A AC
Breaking capacity from 40 to 150 kA rms
Voltage rating: up to 690 V
Versions: 3 and 4-pole. Fixed or drawout.