The power supply has a thermistor inside designed to limit inrush current. After the power supply starts up successfully, the thermistor will automatically lower its resistance to improve working efficiency. The amount of resistance is closely related to internal power supply temperature so once the power supply heats up, the resistance will decrease dramatically.
When the power supply is turned off, the thermistor will still detect high temperature and therefore provide less resistance to inrush current compared to cold boot. Since ST1500 has very higher capacity, its inrush current difference between cold and hot boot is much greater than most power supplies.
The only solution to this limitation is to consult a local electrician and install a new breaker with higher and suitable inrush current tolerance for the ST1500.