Battery Fuses & DC Disconnector 250A | Mersen NH00 Protection

This Mersen fuse and disconnector set gives overcurrent protection and isolation between the battery bank and inverter in off-grid and hybrid solar systems. The NH00 gL/gG fuses handle high continuous DC currents and suit lithium and lead-acid batteries in systems from 8kW upwards. The 250A disconnector allows the battery bank to be isolated safely during maintenance or in an emergency.

Key features for high current dc switch protection

• Fuses, 2x Mersen NH00 gL/gG DC fuses (200A or 250A, one for positive and one for negative battery pole)
• Disconnector, 1x 250A DC disconnector (isolator)
• Enclosure, fuse enclosure included
• Battery compatibility, suitable for lithium-ion and lead-acid battery banks
• Application range, suitable for inverters rated 8kW, 10kW, 11kW and above

Product overview

The cable between battery bank and inverter carries the highest continuous current in an off-grid or hybrid solar system. Correctly rated fuses on both positive and negative conductors protect the battery bank and cabling against short-circuit and overcurrent faults. The DC disconnector isolates the battery bank from the inverter without disconnecting individual battery terminals, which cuts the risk of arcing and shock during maintenance.

NH00 is a standard industrial fuse cartridge format used widely across European solar and energy storage installations. The enclosure and disconnector are built to work together as a single protection and isolation assembly, suitable for wall mounting in a plant room or electrical cabinet.

Applications

• Battery overcurrent protection in off-grid solar systems
• Hybrid inverter battery isolation and protection
• High current DC protection for inverters rated 8kW and above
• Lithium and lead-acid battery bank installations

Installation and safety notes

This assembly must be fitted by a qualified electrician. DC circuits in solar battery systems carry dangerous voltages and high fault currents, and fuse selection must match the cable rating and the maximum discharge current of the battery bank. Isolate all power sources before working on DC connections, and install to IET Wiring Regulations alongside the inverter and battery manufacturers' guidelines.

What's in the box

• 1x Fuse enclosure
• 2x Mersen NH00 gL/gG DC fuses (200A and 250A available, one for positive, one for negative)
• 1x 250A DC disconnector
• 1x Installation instructions