Why Choose the Mersen AJT250 Class J Time-Delay Fuse?
The Mersen AJT250 is a high-capacity Class J time-delay fuse engineered to provide dependable overcurrent protection for demanding industrial and commercial electrical systems. Part of the proven Amp-Trap 2000® AJT series, it combines effective current limitation with a controlled time-delay response that accommodates normal motor-starting and transformer inrush currents.
Designed for mains, feeders and branch circuits, the AJT250 helps protect motors, transformers, switchgear, distribution panels and industrial machinery against damaging overloads and short circuits. Its compact Class J construction supports space-efficient panel layouts while delivering strong fault-interruption performance in high-current applications.
With a rated current of 250 A and voltage ratings of up to 600 V AC and 500 V DC, the AJT250 is suitable for motor control centres, switchboards, fused disconnects and power distribution equipment. Blade-style terminals provide secure installation in compatible Class J fuse holders and switches.
Key Advantages
- Heavy-duty Class J time-delay fuse for demanding industrial systems.
- 250 A current rating for high-capacity feeders and branch circuits.
- 600 V AC and 500 V DC voltage ratings.
- Time-delay characteristics accommodate temporary motor and transformer inrush currents.
- Current-limiting construction helps reduce damaging fault energy.
- Compact Class J format saves valuable switchboard and control-panel space.
Key Features
- Mersen Amp-Trap 2000® AJT series.
- 250 A current rating.
- 600 V AC / 500 V DC rated voltage.
- Class J time-delay construction.
- Blade-style terminal configuration.
- Advanced current-limiting performance.
- SmartSpot® visual open-fuse indication.
- Suitable for mains, feeders, motors, transformers and distribution circuits.
Reliable Protection for High-Current Electrical Systems
The AJT250 is designed to tolerate temporary current surges generated when motors start or transformers are energised. This controlled time-delay behaviour helps minimise unnecessary fuse operation while maintaining effective protection against sustained overloads.
During a severe short circuit, the fuse limits the peak current and energy passed to downstream equipment. This helps reduce thermal and mechanical stress on conductors, contactors, busbars, switchgear and connected machinery, supporting improved electrical safety and reduced equipment damage.
Typical Applications
- Industrial motor control centres.
- Main and feeder circuit protection.
- Large motor branch circuits.
- Transformer primary and secondary protection.
- Power distribution panels and switchboards.
- Fused disconnect switches.
- HVAC and refrigeration installations.
- OEM machinery and industrial automation systems.
