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New industry Technology regarding to Bussmann fuse, ABB breakers, Amphenol connectors, HPS transformers, etc. 

What is Class T Fuse?

Time:2023-12-15   Author:As Beam   Browse:

What is Class T Fuse?

The Class T fuse stands out as a rapid-response current limiting fuse designed to handle a minimum of 200,000 amps, ensuring robust interruption capabilities. Available in both 300 volt AC and 600 volt AC variations, these fuses cover a wide spectrum of electrical applications. Ranging from 1 to 800 amps, their ampere ratings offer versatility across different power needs.


One of the remarkable features of the Class T Fuse is its compact size, occupying only about one-third of the space required by a comparable Class R fuse. This space efficiency doesn’t compromise its performance, though. Classified under UL 248-15, Class T, and certified by CSA, these fuses uphold stringent safety standards.


Several reputable brands offer the Class T fuse, each with its unique attributes. Bussmann’s T-Tron line, for instance, showcases current-limiting and fast-acting fuses renowned for their superior 10X current limitation, crucial in preventing equipment damage resulting from short-circuit events. Their 200 kA interrupting rating adheres to NEC Section 110.9, catering to the demands of modern high-capacity systems.


Bussmann further diversifies its Class T fuse offerings with the JJS series (300VAC, 1-1200A, Fast Acting Fuse) and the JJN series (600VAC, 1-800A, Fast Acting Fuse), both embodying the defining traits of current-limiting fuses.

Bussmann Class T Fuse.jpg


Littelfuse presents its Class T fuses under the POWR-T brand, showcasing models like the JLLS and JLLN fuses, contributing their own technological advancements and safety features.

 Littelfuse Class T Fuse.jpg


Mersen, known for its Amp-Trap brand, contributes to the Class T fuse range with models A3T and A6T, incorporating their expertise and precision engineering into these fuses.

Mersen  Class T Fuse.jpg


These Class T fuses, whether from Bussmann, Littelfuse, or Mersen, signify a commitment to innovation and safety, ensuring a high degree of current limitation during short-circuit scenarios to safeguard critical electrical components.


What are class T fuses used for?

Class T fuses serve as fast-acting semiconductor fuses primarily employed in DC applications. Their core purpose revolves around safeguarding sensitive equipment, notably inverters, against electrical faults. With sizes available up to 1200 Amps and an exceptionally high interrupt rating, these fuses are well-suited to serve as primary circuit protection for substantial battery banks.


Their rapid response and high interrupting capabilities make them a reliable choice for protecting sophisticated and delicate electronic devices. The Class T fuse's design and specifications align with the critical need to prevent damage to inverters and other vulnerable components in the event of electrical faults or short circuits within DC systems.




Class T Fuse Cross Reference (Bussmann, Littelfuse, Mersen)

300V Class T Fuse Cross Reference


Rated VoltageRated CurrentMersenBussmannLittelfuse
300V 1A3T1JJN-1 JLLS001
300V 3A3T3JJN-3 JLLS003
300V 6A3T6JJN-6 JLLS006
300V 10A3T10JJN-10 JLLS010
300V 15A3T15JJN-15 JLLS015
300V 20A3T20JJN-20 JLLS020
300V 25A3T25JJN-25 JLLS025
300V 30A3T30JJN-30 JLLS030
300V 35A3T35JJN-35 JLLS035
300V 40A3T40JJN-40 JLLS040
300V 45A3T45JJN-45 JLLS045
300V 50A3T50JJN-50 JLLS050
300V 60A3T60JJN-60 JLLS060
300V 70A3T70JJN-70 JLLS070
300V 80A3T80JJN-80 JLLS080
300V 90A3T90JJN-90 JLLS090
300V 100A3T100JJN-100 JLLS100
300V 110A3T110JJN-110 JLLS110
300V 125A3T125JJN-125 JLLS125
300V 150A3T150JJN-150 JLLS150
300V 175A3T175JJN-175 JLLS175
300V 200A3T200JJN-200 JLLS200
300V 225A3T225JJN-225 JLLS225
300V 250A3T250JJN-250 JLLS250
300V 300A3T300JJN-300 JLLS300
300V 350A3T350JJN-350 JLLS350
300V 400A3T400JJN-400 JLLS400
300V 450A3T450JJN-450 JLLS450
300V 500A3T500JJN-500 JLLS500
300V 600A3T600JJN-600 JLLS600
300V 700A3T700JJN-700 JLLS700
300V 800A3T800JJN-800 JLLS800
300V 1000A3T1000JJN-1000 JLLS1000
300V 1200A3T1200JJN-1200 JLLS1200

600V Class T Fuse Cross Reference

Rated VoltageRated CurrentMersenBussmannLittelfuse
600V1A6T1JJS-1 JLLS001
600V3A6T3JJS-3 JLLS003
600V6A6T6JJS-6 JLLS006
600V10A6T10JJS-10 JLLS010
600V15A6T15JJS-15 JLLS015
600V20A6T20JJS-20 JLLS020
600V25A6T25JJS-25 JLLS025
600V30A6T30JJS-30 JLLS030
600V35A6T35JJS-35 JLLS035
600V40A6T40JJS-40 JLLS040
600V45A6T45JJS-45 JLLS045
600V50A6T50JJS-50 JLLS050
600V60A6T60JJS-60 JLLS060
600V70A6T70JJS-70 JLLS070
600V80A6T80JJS-80 JLLS080
600V90A6T90JJS-90 JLLS090
600V100A6T100JJS-100 JLLS100
600V110A6T110JJS-110 JLLS110
600V125A6T125JJS-125 JLLS125
600V150A6T150JJS-150 JLLS150
600V175A6T175JJS-175 JLLS175
600V200A6T200JJS-200 JLLS200
600V225A6T225JJS-225 JLLS225
600V250A6T250JJS-250 JLLS250
600V300A6T300JJS-300 JLLS300
600V350A6T350JJS-350 JLLS350
600V400A6T400JJS-400 JLLS400
600V450A6T450JJS-450 JLLS450
600V500A6T500JJS-500 JLLS500
600V600A6T600JJS-600 JLLS600
600V700A6T700JJS-700 JLLS700
600V800A6T800JJS-800 JLLS800

New industry Technology regarding to Bussmann fuse, ABB breakers, Amphenol connectors, HPS transformers, etc. 

TAG:   Class T Fuse Mersen Cross Reference