Krzysztof_Bo wrote: 1. Lack of selectivity at the meter, you need to change the overcurrent switch to, for example: STV with a D01 / 02 insert.
I would have refrained from this "must" and with topics, not knowing the IPZ. Additionally, the inserts may, in certain situations, reduce the functionality of the installation and increase the costs of its operation.
zdzisiek1979 wrote: There is probably something like self-cleaning of contacts.
This applies to both contactors and disconnectors.
And if this process did not exist, the producers would not produce such a large range of currents. It's a good idea to produce a 16A or 40 switch disconnector if you can do one or two for 80A or 100A.
It's practically only about the price and dimensions, because larger currents need more "meat" (especially when it comes to contactors).
The contacts, being turned on, do not get dirty because they do not have how (unless they are badly hurt, but this is a camera defect). It is only when disconnecting loads (especially capacitive or inductive) that an arc arises, which can burn out these contacts if there is no appropriate extinguishing, which may result in quick wear of the apparatus, and even sticking of the contacts.
Additionally, even having a circuit in which 100A can flow and a 100A switch, no one checks the value of the current flowing in the circuit during disconnection, and usually even before using the switch, as much of the load as possible is turned off so as not to load it too much.
