MIDI Fuse

MIDI fuse – bolt-down fuse by Littelfuse for medium current classes in vehicle electrical systems

The MIDI fuse by Littelfuse is a bolt-down fuse forming the transitional design between the classic standard blade plug-in fuse and the larger bolt-down protection elements of the family. It is used in truck and commercial vehicle electrical systems primarily for medium current classes – wherever plug-in contacts would be too small and main fuses would be oversized. At SULEJ Ladebordwand you will find the MIDI fuse as a balanced protection solution for secondary distribution points, higher-power control unit branches and medium-duty consumers with a screw connection.

Medium-format design of the MIDI series and connection principle

The MIDI fuse has a flat, screw-mounted design with two connection tabs whose hole spacing lies between a standard blade fuse and a large main fuse. The PPA thermoplastic housing protects a centrally placed fuse element with Slo-Blo® time-delayed tripping per ISO 8820. The series is rated for 32 V and 58 V electrical system voltages and covers a typical current range of approximately 30 to 200 A. The breaking capacity is 2000 A and the permitted operating temperature ranges from -40 °C to +125 °C. Thanks to its bolt-down mounting, the MIDI offers a far more vibration-resistant contact compared with standard plug-in fuses – without taking up the space of a large main fuse.

Use in secondary distribution and selecting the MIDI

The MIDI fuse is preferably used in secondary distribution points and branches in which individual sections of the vehicle electrical system sit above the typical standard blade fuse class but below the main current paths. Selection criteria are nominal current (typically 30–200 A), electrical system voltage (32 V or 58 V) and the hole spacing of the connection tabs, which must match the existing MIDI mounting. With every replacement, attention should be paid to a firm screw seat and clean contact surfaces, since at this current class contact resistance can already generate noticeable heat.

Benefits at a glance

• Transitional design between standard blade fuse and large main fuse
• Bolt-down connection for a vibration-resistant seat in secondary distribution
• Typical current range approx. 30–200 A, 32 V / 58 V electrical system voltages
• Slo-Blo® time-delayed tripping per ISO 8820
• PPA thermoplastic housing, breaking capacity 2000 A, -40 °C to +125 °C

A correctly sized MIDI fuse closes the current gap between small plug-in fuses and large bolt-down main fuses without unnecessary oversizing.