Edison current-limiting Class CC fuses interrupt overcurrents within their interrupt rating, limit peak let-through current, and limit the clearing time at rated voltage. Available in ratings up to 30A, the HCLR series is well-suited for resistive heating and lighting loads; HCTR series for power transformers or solenoids; and EDCC series for motor protection.
Class CC fuses are current limiting fuses with rejection tips on the bottoms to prevent them from being used in holders not rated similarly.
A Current-Limiting Fuse meets the following three conditions:
Select the "Technical Info" tab above (or see our catalog) to refer to the fuse selection guide, which includes a general summary of the specifications included for each fuse type.
This selection guide does not include the many variables that can exist for specific situations such as local codes, unusual temperature, or other operating conditions.
When selecting fuses, be sure to comply with any applicable PUBLIC SAFETY standards that apply to Overcurrent Protection Devices (OPD).
Best applied for resistive heating and lighting loads.
Ideal as primary protection for control power transformers (such as our CPT Series) or solenoids.
Specifically designed for motor protection, provides excellent current limiting capabilities. Use for protection of small horsepower motor circuits or other circuits requiring small dimension, time-delay fuses. Recognized for NEC branch circuit protection and Type 2 coordinated applications for IEC or NEMA motor starters/contactors. For control transformer applications, refer to HCTR series fuses.
I2t (Ampere Squared seconds): A measure of the thermal energy associated with current flow. I2t is equal to (IRMS)2 x t, where t is the duration of current flow in seconds.
Clearing I2t: The total I2t passed by a fuse as the fuse clears a fault, with t being equal to the time elapsed from the initiation of the fault to the instant the fault has been cleared.
Melting I2t: The minimum I2t required to melt the fuse element.
Ampere Rating: The continuous current carrying capability of a fuse under defined laboratory conditions. The ampere rating is marked on each fuse.
Available Fault Current: The maximum short-circuit current that can flow in an unprotected circuit.
Breaking Capacity / Interrupting Rating: A fuse must be able to open the circuit under a short circuit condition without endangering its surroundings. The breaking capacity or interrupting rating of a protective device is the maximum available current, at rated voltage, that the device can safely open without rupturing.
Current-Limiting Range: The available fault currents a fuse will clear in less than ½ cycle, thus limiting the actual magnitude of current flow.
Current Rating: The current rating of a fuse identifies its current-carrying capacity based on a controlled set of test conditions. Each fuse is marked with its current rating.
Element: A calibrated conductor inside a fuse that melts when subjected to excessive current. The element is enclosed by the fuse body and may be surrounded by an arc-quenching medium such as silica sand. The element is sometimes referred to as a link.
Fast-Acting Fuse: This is a fuse with no intentional time-delay designed into the overload range. It is sometimes referred to as a "single-element fuse" or "non-delay fuse."
Fault Current: Short-circuit current that flows partially or entirely outside the intended normal load current path of a circuit component. Values may be from hundreds to many thousands of amperes.
Ferrule: The cylindrical brass, bronze or copper mounting terminals of fuses with amp ratings up to 60 amperes. The cylindrical terminals at each end of a fuse fit into fuse clips.
Overcurrent: A condition which exists in an electrical circuit when the normal load current is exceeded. Overcurrents take on two separate characteristics-overloads and short circuits.
Time delay fuse: A fuse with a built-in time delay that allows temporary and harmless inrush currents to pass without operating, but is so designed to open on sustained overloads and short circuits.
Voltage rating: A maximum open circuit voltage in which a fuse can be used, yet safely interrupt an overcurrent. Exceeding the voltage rating of a fuse impairs its ability to clear an overload or short circuit safely.