The electronic counter is a measuring instrument coupled with a circuit breaker that removes the current in case you exceed the maximum installed power.
This depends on the energy supply contract. When you open a new user, in fact you choose the maximum available power you have at the same time consuming energy.
Remember to carefully read the supply contracts for both new users and energy supplier exchanges. Often according to the installed power you pay accordingly, so choose with prudence.
To calculate and choose the power available to your counter you will need to consider in addition to the consumption of individual appliances and lamps also other factors.
You will need to evaluate how many of these work simultaneously.
Only this way can you determine the real need.
Most homes have power installed from 3kW to 6kW, although the sum of household appliances consumption is higher.