Replacing a Blue Sea Class T fuse requires more than reading its amperage. This family uses two different physical fuse lengths and holder styles. Identify the fuse part number, then match it to the holder's original MPN before selecting the electrical rating required by the circuit.
First identify the holder size
Use Blue Sea 5007100 insulated holder for the smaller Class T fuse family. The 110, 125, 150, 175 and 200A fuses listed below share this physical size.
Use Blue Sea 5502100 insulated holder for the larger Class T family. The 225, 250, 300 and 350A options in this catalog use that size.
A Class T fuse's labelled amperage and physical holder group are separate identification checks.
Smaller Class T fuse part numbers
The smaller group requires the 5007100 holder. Do not replace a blown fuse with a higher rating without checking the circuit's approved protection.
Larger Class T fuse part numbers
These larger fuses fit the 5502100 size holder, not the shorter 5007100.
What to check on an existing installation
Read the old fuse's rating, inspect the holder MPN and confirm the correct Class T format before replacing a part. Check for heat damage, loose terminals and cable sizing; investigate the cause of a blown fuse before re-energizing.
Always select the fuse rating for the actual protected circuit. Never increase a fuse rating merely to prevent nuisance trips or because a larger-rated holder is installed. Fuse blocks are sold without the separately selected fuse.
Class T and MRBF, ANL, MEGA/AMG and ATO/ATC are different fuse formats. Do not substitute between those families without a manufacturer-approved redesign.
Match a Class T part-number listing
Open the exact model for listing details and current availability.
Blue Sea 5112 110A Class T Fuse
A 110-amp Class T fuse. Confirm holder size and conductor-protection requirements before replacement.
Check listing details and availability
Blue Sea 5113 125A Class T Fuse
A 125-amp Class T fuse. Confirm holder size and conductor-protection requirements before replacement.
Check listing details and availability
Blue Sea 5114 150A Class T Fuse
A 150-amp Class T fuse. Confirm holder size and conductor-protection requirements before replacement.
Check listing details and availability
Blue Sea 5115 175A Class T Fuse
A 175-amp Class T fuse. Confirm holder size and conductor-protection requirements before replacement.
Check listing details and availability
Blue Sea 5116 200A Class T Fuse
A 200-amp Class T fuse. Confirm holder size and conductor-protection requirements before replacement.
Check listing details and availability
Blue Sea 5117 225A Class T Fuse
A 225-amp Class T fuse. Confirm holder size and conductor-protection requirements before replacement.
Check listing details and availability
Blue Sea 5118 250A Class T Fuse
A 250-amp Class T fuse. Confirm holder size and conductor-protection requirements before replacement.
Check listing details and availability
Blue Sea 5119 300A Class T Fuse
A 300-amp Class T fuse. Confirm holder size and conductor-protection requirements before replacement.
Check listing details and availability
Blue Sea 5120 350A Class T Fuse
A 350-amp Class T fuse. Confirm holder size and conductor-protection requirements before replacement.
Check listing details and availability
Blue Sea 5007100 Class T Holder
Holder size 110–200 A; verify the original mounting hardware and cover.
Check listing details and availability
Blue Sea 5502100 Class T Holder
Holder size 225–400 A; verify the original mounting hardware and cover.
Check listing details and availabilityOther fuse and battery reference pages
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