A reasonable reserve also provides scope for an extension of the lighting installation.
On the one hand, the power supplies fuse could be triggered by the of the lamps.
To receive this rating, a power supply must be at least 80 percent efficient, meaning that a maximum of 20 percent of power is lost as heat.
This necessitates efficiency and transient response tuning so the system receives the right amount of power at all times.
If your system is drawing 500 watts, your power supply will supply 500 watts, regardless of maximum capable output.
The calculated maximum wattage demand could differ from the true power consumption of your system.