Each fuse has a specific ampere rating, which is its continuous current-carrying capability. The ampere rating of the fuse chosen for a circuit usually should not exceed the current-carrying capacity of the circuit. For example, if a circuit’s conductors are rated for 10 amperes, the largest fuse that should be selected is 10 amperes.
However, there are circumstances where the ampere rating is permitted to be greater than the current-carrying capacity of the circuit. For example, motor and welder circuits’ fuse ratings can exceed conductor ampacity to allow for inrush currents and duty cycles within limits.
The voltage rating of a fuse must be at least equal to the circuit voltage. The voltage rating of a fuse can be higher than the circuit voltage, but never lower. A 600 volt fuse, for example, could be used in a 480 volt circuit, but a 250 volt fuse could not be used in a 480 volt circuit.
Fuses are also rated according to the level of fault current they can interrupt. This is referred to as ampere interrupting capacity (AIC). A fuse for a specific application should be selected so that it can sustain the largest potential short circuit current that could occur in the application. Otherwise, the fuse could rupture, causing extensive damage, if the fault current exceeded the interrupting ability of the fuse.
However, there are circumstances where the ampere rating is permitted to be greater than the current-carrying capacity of the circuit. For example, motor and welder circuits’ fuse ratings can exceed conductor ampacity to allow for inrush currents and duty cycles within limits.
The voltage rating of a fuse must be at least equal to the circuit voltage. The voltage rating of a fuse can be higher than the circuit voltage, but never lower. A 600 volt fuse, for example, could be used in a 480 volt circuit, but a 250 volt fuse could not be used in a 480 volt circuit.
Fuses are also rated according to the level of fault current they can interrupt. This is referred to as ampere interrupting capacity (AIC). A fuse for a specific application should be selected so that it can sustain the largest potential short circuit current that could occur in the application. Otherwise, the fuse could rupture, causing extensive damage, if the fault current exceeded the interrupting ability of the fuse.
No comments:
Post a Comment