The wattage of low voltage 300V is:
W_low = (300V-15V)*7.92mA
= 285V*7.92mA
= 2.2572 W
And to choose the Wattage values as 5 times of calculated values:
W = 2.2572 W * 5
= 11.286 W
If you don't want to use the W values that high then at least it should be choose as 3 times of calculated values.
You can calculate -- The wattage of low voltage 350V is:
