Blue Sea 225 to 400A Class T Fuse Block Holder w/ Insulating Cover

High-current Class T fuse protection for inverters, battery banks and DC systems

When you’re running high-demand equipment such as inverters, DC-DC chargers or large battery banks, the protection device needs to handle serious fault current without becoming the weak link. The Blue Sea Class T Fuse Block Holder is built for 225–400A Class T (JJN) fuses and is commonly used in marine, caravan, 4WD and off-grid power systems where reliable, fast-acting overcurrent protection matters.

Class T fuses are valued for their high interrupt capacity and rapid response to short circuits—particularly important in lithium battery and high-power inverter installs where fault currents can rise extremely quickly. This fuse block helps you implement that protection in a clean, serviceable way, with robust electrical contacts and a layout designed for heavy cabling.

Safer installs with a clear insulating cover

The included clear insulating cover reduces the risk of accidental contact with live terminals while still allowing quick visual checks during inspection and maintenance. It’s also designed to help meet ABYC/USCG expectations for covered battery and DC distribution connections—useful for marine compliance and for anyone building a professional-grade installation.

Built to handle heat, vibration and real-world loads

High-current connections generate heat when they’re not engineered properly. This holder uses tin-plated copper mounting blocks to support efficient conductivity and corrosion resistance, helping reduce contact losses that can lead to hot terminals. The hardware and stud format are well suited to secure cable lugs, making it a solid option for demanding environments such as engine bays, battery compartments and power cabinets.

Designed for modern DC power systems (up to 160V DC)

With suitability up to 160V DC, this fuse holder supports more than just 12V setups. It can be used in 24V and 48V systems commonly found in marine and off-grid installations, and is a practical choice when you want consistent protection architecture across different battery voltages. Selecting the correct fuse rating remains important—this holder is compatible with the fuse range, while system design should consider expected continuous current, surge loads and installation conditions.

Key features

• Accepts Class T (JJN) fuses from 225A to 400A (fuse sold separately)
• Clear insulating cover helps prevent accidental contact and supports compliant installs
• Tin-plated copper blocks for conductivity and corrosion resistance
• 3/8"-16 stud terminals suit heavy-duty lugs (up to 4/0 AWG)
• 160V DC capable for 12V, 24V and 48V DC system architectures

Where this fuse block fits best

This Blue Sea fuse holder is often selected as a main battery fuse close to the positive terminal, or as dedicated protection for a high-current inverter. It’s also ideal when upgrading from smaller fuse styles where interrupt ratings and physical robustness may be limiting factors.

Note: This is the holder only; the Class T fuse is purchased separately so you can choose the amperage appropriate for your cable size, load profile and manufacturer recommendations.

Build a safer, cleaner high-current DC system

If you’re wiring a serious inverter or battery bank and want a professional fuse mount with an insulating cover and high-current terminals, add this Blue Sea Class T fuse block to your build and pair it with the correct Class T fuse for your system.