A characteristic of all Fuse Links is that the speed at which they operate is directly linked to the level of the fault current. Example: a 100 Amp Fuse Link might take 10 minutes to operate at 200 Amps but would operate in one tenth of a second at 1000 Amps. A graph plotting the operating time of a Fuse Link against fault current is called a Time - Current graph. Time - Current curves are produced according to BS or IEC Standards, which are termed average curves. This average allows for manufacturing tolerances on a given type of Fuse Link. Time - Current curves according to North American Standards are plotted differently with each Fuse Link design having two curves. These represent the fastest time that the Fuse Link would operate for given values of current. The second plots the slowest time that the same Fuse Link would operate at the same currents.