TBS Class-T Fuse 175 A / 125 V DC

The Class T fuse protects cables, batteries, and connected components in high-power DC systems against overcurrent and high short-circuit currents. Its fast-acting and current-limiting characteristics make it particularly suitable for lithium battery systems, inverters, and DC main distribution panels.

Typical applications include solar storage systems, off-grid systems, RVs, adventure vehicles, boats, and other mobile or stationary energy systems. Proper sizing of the fuse, the wiring, and the fuse holder used is essential.

Why Use a Class T Fuse?

Lithium batteries have low internal resistance and can deliver very high short-circuit currents in the event of a fault. Class T fuses respond quickly and limit the energy passed through. This reduces the thermal and magnetic stress on cables and downstream components.

The breaking capacity indicates the fault current a fuse can safely interrupt under the specified conditions. For the Littelfuse JLLN series, it is 20 kA for direct current. This value should not be confused with the higher AC breaking capacity.

Selecting the Right Fuse

The correct fuse rating depends on the maximum operating current as well as the rated currents of the cable, battery, and connected devices. In addition, the maximum system voltage, the required breaking capacity, and the fuse’s characteristics must be taken into account.

The component with the lowest permissible current or voltage limit is always the determining factor. Therefore, the fuse must not be selected based solely on the battery capacity or the inverter’s power rating.

Victron Lynx Class-T Power In and TBS DCM

The Victron Lynx Class-T Power In connects and protects up to two lithium battery strings. It features a positive and negative busbar as well as connections for two Class-T fuses and can be integrated into the modular Victron Lynx distribution system.

Not every Class-T fuse variant is automatically suitable for the Lynx Class-T Power In. Before making a selection, the permissible fuse rating, mechanical dimensions, and terminal size must be verified against the current Victron documentation.

Alternatively, various Class-T fuse holders are available in the modular TBS-DCM system. The fuse holder used must match the size, rated current, and terminal configuration of the selected fuse.

Technical Specifications

For solar, mobile, and marine systems

Class T fuses are suitable for DC systems with high available short-circuit currents. These include lithium battery banks for inverters, solar and off-grid systems, recreational vehicles, specialty vehicles, and properly installed onboard power systems on boats.

For mobile and marine installations, additional considerations include the installation environment, protection against accidental contact, mechanical mounting, and the suitability of the fuse holder. The fuse itself is not a substitute for proper system design.

Frequently Asked Questions About Class T Fuses

• Why are Class T fuses used for lithium batteries?

  
  

  Lithium batteries can deliver very high short-circuit currents. Class-T fuses combine a fast response with high breaking capacity and are therefore suitable for many high-power lithium battery systems.

• What does a DC breaking capacity of 20 kA mean?

  
  

  It refers to the maximum direct current that the fuse can safely interrupt under specified conditions. The required breaking capacity depends on the potential short-circuit current of the battery bank.

• Is every Class-T fuse compatible with the Victron Lynx Class-T Power In?

  
  

  No. The fuse rating, dimensions, and connector size must comply with Victron’s specifications. Compatibility must be verified using the latest product documentation before purchase.

• Which TBS fuse holder is required?

  
  

  The holder must match the fuse’s size, rated current, and terminal configuration. Additionally, the holder’s maximum system voltage must be taken into account.

• Can a tripped Class T fuse be reused?

  
  

  No. Class T fuses are fusible links and must be replaced after tripping. Before replacing them, the cause of the overcurrent or short circuit must be determined.