Specifications

9
Overcurrent Protection Devices
Because current flow in a conductor always generates heat,
the greater the current flow, the hotter the conductor. Excess
heat is damaging to electrical conductors. For that reason,
conductors have a rated continuous current carrying capacity or
ampacity. Current beyond the rated capability of a conductor is
referred to as overcurrent. Overcurrent can result from a short
circuit, an overload, or a ground fault.
Normal Current Flow
Excessive Current Flow
A short circuit occurs when two bare conductors touch
causing the resistance between the conductors to drop
significantly. This reduction in resistance causes an immediate
and destructive increase in current. An overload is a typically
a much lower current than a short circuit. An overload occurs
when too many devices are connected to a circuit or when
electrical equipment is made to work beyond its rated
capabilities. Finally, a ground fault occurs when current takes
an undesired path to ground. The level of ground fault current
depends on the resistance of the path and the amount of
voltage applied.