However, we have no heat generated from the fuse and the copper dummy fuse acts as a heatsink, extracting heat from the clip area much better than a fuse would do. Most heat comes from the contact resistance of the clips the current is turned up till a certain temperature rise occurs, and this current value is considered to be the rated current of the fuse holder. In this case the fuse resistance is negligible. UL measures the temperature rise of a fuse holder using a solid copper dummy fuse. ![]() This means that only fuses of this type with a rated current of 1 A maximum can be used in combination with the fuse holder under consideration. 1 A show a maximum power dissipation of 2.5 W or less. Fuse links of this type with rated currents of max. High breaking capacity fuses specified in IEC 127, part 2 standard sheet I, however, show power dissipations up to 4 W at highest ratings (see table 4.3). For these fuse types the fuse holder under consideration is able to accept all fuse ratings up till 6.3 A of this type of fuse links. Quick-acting fuse links specified in IEC 127 part 2, standard sheet II, have power dissipations which do not exceed 2.5 W (see table 4.3). As an example, let us assume that the rated accepted power of a fuse holder is 2.5 W. Basically, this means that the rated current is not a fixed value. This rated accepted power determines the rated current. For example, it means that at a power dissipation of 4 W (by a fuse link placed in the fuse holder) temperatures of the fuse holder should not exceed certain limit values as specified in the standard. ![]() The rated accepted power is, according to IEC 257, "A stated value of power dissipation (of a fuse link) which a fuse-base or fuse holder can accept under prescribed conditions of use and behavior." Rated values of accepted power are 1.6 W, 2.5 W or 4 W. According to IEC 257, the rated current is determined by the rated accepted power of a fuse holder. Considerable differences exist between the IEC and the UL standards regarding the rated current of a fuse holder. In the following, some of the most important differences between the two standards will be indicated.įrom an application point of view, a fuse holder is characterized by the features discussed in the previous section by its rated values for voltage, current, and accepted power. In the case of fuse links, compliance with the UL-standard does not usually mean that the fuse holder under consideration meets IEC-requirements and vice versa. 2 to this publication dated January 1989.īoth standards show considerable differences. IEC-publication 257 (1968) and Amendment no.The most important standards for fuse holders, which specify requirements, characteristics and testing methods are: How much is available to spend on safety and reliability?.Should the fuse only be accessible from outside the appliance?.Should the end customer of the appliance have access to change the fuse?.How often will the fuse need to be replaced?.Will the fuse need to accessible for replacement?.The first step is to answer the following questions: Available in-line bodies and stackable panel-mount bodies made of heat-resistant thermoplastic, plus configurations with DFK-2 leaf spring terminals, DFK-2 contact coils, or 90° bent, solderable tin-plated copper alloy contacts make it simple to build the fuse holder required for your application.ĭesigned for 32V ATO® fuses up to 20 amps or 30 amps depending on the configuration, this fuse holder series is also compatible with FKS fuses at 80V DC.Selection of the Fuse and Holder Solution Get the ATO® in-line or stackable panel-mount blade-style fuse holder you need with the ATO® FKH Series 32V Blade Fuse Holder. The sale and use of Littelfuse products is subject to Littelfuse Terms and Conditions of Sale, unless otherwise agreed by Littelfuse. "Littelfuse" includes Littelfuse, Inc., and all of its affiliate entities. Littelfuse shall not be liable for any claims or damages arising out of products used in applications not expressly intended by Littelfuse as set forth in applicable Littelfuse documentation. Warranties granted by Littelfuse shall be deemed void for products used for any purpose not expressly set forth in applicable Littelfuse documentation. ![]() Littelfuse products are not designed for, and shall not be used for, any purpose (including, without limitation, automotive, military, aerospace, medical, life-saving, life-sustaining or nuclear facility applications, devices intended for surgical implant into the body, or any other application in which the failure or lack of desired operation of the product may result in personal injury, death, or property damage) other than those expressly set forth in applicable Littelfuse product documentation.
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