Does a fuse/circuit breaker blow easier when there is high load on the grid? Short version: When there is a high load on the power grid in general, does it make it more likely that my fuse will blow?
Full version: I'm renting an apartment in Rome, where we are currently experiencing a heat wave. When running the air conditioning unit on max, the circuit breaker will regularly trip after an hour or so, taking out the power in the apartment. Since I have to go down to reset it, I know that my apartment is the only one affected, i.e. my power is lost, but no other apartments in the building are affected.
When asking my landlord if he can rectify the situation (e.g. by installing a circuit breaker that can handle a slightly higher current), he says that the power grid is overloaded by people using their AC in the warm weather, and there is nothing he can do. 
I intuitively find it hard to understand that an overloaded grid will lead to my circuit breaker tripping easier, but I don't have a super strong grasp on alternating currents and building/city level grids. Can anyone help me understand, or alternatively make my case?
 A: First of all, fuses blow when the current they receive is higher than what they are expected to handle. The main reason for that is either the fact that you have contracted a certain amount of power to the energy company and they are limiting the current you can receive because, otherwise, you would be getting more than paid or because, otherwise, the amount of current that would be going through the circuit could be dangerous to you.
That being said, if the flat circuit connections are well done, what the other neighbours do should not affect you -or, at least, should not affect just you- because the connections between flats -and also between rooms inside flats- are made in parallel so that one does not affect the others.
In other words, the amount of current that you receive in "your part of the flat's circuit" should be independent of the one the others receive.
A: The explanation could be partially true if


*

*The heavy city-wide load causes a drop in overall line voltage;

*Your air-conditioner, attempting to supply the right energy to the air-conditioner motor, responds to the low supply voltage by increasing the current drawn through your circuit-breaker.  See this article https://en.wikipedia.org/wiki/Brownout_(electricity) for details...

*Your circuit-breaker, being triggered on the low side of the stated value, triggers...


You may have other high loads in your apartment, or possibly creative wiring adding someone else's load on your breaker... 
