Also, be aware that the resistance of incandescent lamps are very low when cold. It can be as much as 1/10th of the hot resistance. Therefore can draw up to 10 times the current at start up, as it will draw when hot. If you are using "fast-blo" fuse and the lamp is switched on when the line voltage is at peak (230x1.4=322V) it will instantaneously draw much more than 2A. "Slo-blo" fuses are designed to allow for this brief current surge.
Attached are a couple of graphs, that someone made, to show the steady state relationship of voltage, current, resistance, and heat of a 120VAC 100W lamp.
Ken