Blue Sea Systems Class T Fuse Block with Insulating Cover, 160V DC

Overview

The Blue Sea Systems Class T Fuse Block with Insulating Cover is a high-current fuse holder range for Class T fuses on DC marine electrical systems up to 160V DC. It is made for fast-acting overcurrent protection in demanding circuits such as inverter feeds, large battery banks, chargers, and other high-load electronics where a short circuit needs to be interrupted quickly.

Across the range, the block accepts cable up to 4/0 AWG and uses tin-plated copper fuse mounting blocks to carry high current with low resistance. The insulating cover helps protect exposed conductors and satisfies ABYC and USCG insulation requirements, while cover breakouts let the installer route heavy cable from different directions without forcing an awkward bend.

This is a practical choice for boats where high-current wiring needs to stay serviceable after installation. The open stud layout gives room around large lugs, and the covered design suits battery compartments, inverter locations, and protected machinery spaces where vibration, heat, and accidental contact are real concerns.

Key features

• Supports Class T fuses for fast-acting circuit protection on high-current DC loads such as inverters and other onboard electronics.
• Rated for DC systems up to 160V, with variant fuse ranges covering 110 to 200A and 225 to 400A applications.
• Accepts cable up to 4/0 AWG, which helps with large battery and inverter cable runs common on cruising and power management systems.
• Insulating cover satisfies ABYC and USCG insulation requirements and helps reduce the risk of accidental contact with live terminals.
• Cover breakouts allow wire access from multiple directions, making the block easier to fit in tight electrical spaces.
• Tin-plated copper fuse mounting blocks help carry high current and resist corrosion in marine electrical environments.
• Four-stud layout gives installers room to land large cable lugs without crowding the fuse connection.

Variants

This product is offered in multiple Class T fuse block configurations for different fuse ranges, ignition protection requirements, and terminal stud sizes.

The main differences are the supported Class T fuse range, whether the block is ignition protected, and the terminal stud size used for the main cable connections. All listed configurations are for systems up to 160V DC and use an insulating cover.

• 5007100: Class T fuse range 110 to 200A, ignition protected, with 1/4"-20 terminal studs. This version suits lower high-current Class T fuse installations where ignition protection is required and the cable lugs match the smaller stud size.
• 5502100: Class T fuse range 225 to 400A, ignition protected, with 5/16"-18 terminal studs. This configuration is used for higher-current protected circuits that still require an ignition-protected fuse block.
• 5502: Class T fuse range 225 to 400A, not ignition protected, with 3/8"-16 terminal studs. This version fits high-current installations where ignition protection is not required and larger 3/8" ring terminals are being used.

Installation and fit

Match the selected block to the fuse amperage, terminal stud size, cable lug hole size, and the location where it will be mounted. For inverter and battery circuits, the fuse block should be installed as close to the power source as the system layout and applicable marine electrical practices allow.

Use properly crimped ring terminals that match the cable size and stud size. The cover should be fitted after connections are tightened so the terminals remain protected while still allowing service access when the fuse needs inspection or replacement.

Compatibility and system use

These blocks are for Class T fuses and should not be mixed with other fuse formats. They are well suited to high-current DC circuits on cruising boats, fishing boats, and larger power systems where inverter loads or large battery banks require fast short-circuit protection.

The ignition-protected variants are the correct style to consider for spaces where ignition protection is required by the installation. The non-ignition-protected 5502 is better matched to protected electrical areas where that rating is not needed.