The Victron Lynx Shunt M10 includes a bus bar for the position where some installers expect a fuse. Whether that position should use the bus bar or a fuse depends on how the complete system is protected.
Start with the entire protection plan
Overcurrent protection should be designed as a complete system. An available fuse position does not automatically mean another fuse is required. First determine whether the connected conductors and equipment are already protected at the correct locations.
Lithium batteries and Class T protection
Big Beard Battery typically uses Class T fuses for lithium battery-side protection because of their high interrupting capability. A Class T fuse does not fit in the Lynx Shunt M10 fuse position. Victron offers the Lynx Class-T Power In for systems that need Class T protection integrated into the Lynx layout.
When the bus bar is appropriate
If the lithium battery bank and the circuit on the other side of the shunt are already correctly fused, the supplied bus bar is often the appropriate choice. It avoids adding redundant fuse resistance and another connection point.
When a fuse may be appropriate
A fuse in the shunt position may be useful when the circuit is not otherwise protected appropriately or with a different system design or battery chemistry. It should not be treated as the primary lithium battery protection point without verifying its interrupt rating, the available fault current, and every conductor in the circuit.
Fuse type, rating, and location must be determined from the system fault-current requirements, conductor ampacity, and equipment manuals. Have a qualified designer review the protection plan if you are uncertain.
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