OT Main MCB required or not

In all of our panels we have the supply go though the main 4 pole disconnect switch, to main MCB and from there to thermomagnetic circuit breakers which supply motor contactors and to single pole MCBs which supply power supplies, control transformers or any other single phase loads.

Is the main MCB really required in all cases or it's possible to feed thermomagnetic circuit breakers and single pole MCBs directly from the main disconnect switch without installing the main MCB?

I'm in the US and going by UL requirements, so take with a grain of salt. I'm not sure of the IEC rules.

If you have a single motor, you can use a single MCB for the motor only and drive the control circuit with a transformer / power supply with it's own separate fuse / MCB.

Any more than one motor, and you will want a main MCB to protect the overall system from overloading.

Personally, I always fuse the main disconnect, since adding a motor / removing a motor / changing a motor size can often be accomplished just buy changing out the fuses. With a circuit breaker, you will likely need to get a whole new one.

The MCB is not compulsory to EU standards to fit one as standard. I guess what you are manufacturing falls under 60204-1.

That said, there are situations where an MCCB, MCB, fuses etc.. need installing for a number of reasons. E.G conductor length from the main disconnect to the circuit protection, fault current limiting... etc.

The control panel will be rated for a certain short-circuit current for a certain time at the incoming supply.
Components in the control panel must be able to sustain this current for the rated time, unless there is something that reduces to current to a lower level.
edit: And the fuses and MCCBs must be able to break the rated short-circuit current.

Compnents that can reduce the short circuit current are:
Fuses.
MCCBs (that have a short circuit current limiting capability).
Transformers (it is one of the reasons for having a control voltage transformer).
Wiring/cables if they are long (just mentioned for completeness, inside control cabinets you normally do not consider the wiring/cables as current-limiting devices).

We almost never use "main" MCCBs for reducing the short circuit current.
Main-switch, power bus-bar, and the first bank of MCCBs (for motors and power-supply circuits) must all be rated for the incoming short-circuit current and time.

The rare exception has been when a customer has specified a very high short-circuit current. In that case we have had to place MCCBs with current limiting ability on front of some of the motor MCCBs that were not rated for the requited short circuit current.

Thanks guys.
Our panels are usually really small up to 32A and with 3-4 small motors.