Why Choose the Mersen A4BQ900 Class L Time-Delay Fuse?
The Mersen A4BQ900 is a premium Class L time-delay fuse designed to provide outstanding overcurrent and short-circuit protection for industrial and commercial power distribution systems. As part of the renowned Mersen Amp-Trap 2000® A4BQ series, it is engineered for service entrance equipment, switchgear, feeder circuits and other high-capacity applications where dependable circuit protection is essential.
Amp-Trap 2000® A4BQ fuses deliver up to 20% greater current limitation than conventional Class L fuses, reducing short-circuit let-through current and energy to better protect downstream equipment. Their integrated 4-second time-delay characteristic at 500% of rated current allows harmless inrush currents from motors, transformers and other inductive loads to pass without nuisance operation.
With a rated current of 900 A, voltage ratings of 600 V AC and 500 V DC, and exceptional interrupting capability, the A4BQ900 provides reliable protection for demanding industrial electrical systems while helping minimise equipment damage during fault conditions.
Key Advantages
- Premium Class L time-delay fuse for industrial power distribution.
- 900 A current rating for high-capacity electrical systems.
- 600 V AC / 500 V DC voltage ratings.
- Amp-Trap 2000® technology provides up to 20% greater current limitation.
- 4-second time delay prevents nuisance operation during motor and transformer start-up.
- 300 kA AC self-certified interrupting capability with UL-witnessed testing.
Key Features
- Mersen Amp-Trap 2000® A4BQ series.
- 900 A ampere rating.
- 600 V AC / 500 V DC rated voltage.
- Class L current-limiting time-delay fuse.
- 4-second minimum time delay at 500% rated current.
- 200 kA AC interrupting rating.
- 100 kA DC interrupting rating.
- 300 kA AC self-certified performance with UL-witnessed testing.
- Pure silver fuse links for low let-through current.
- Fibreglass body for dimensional stability.
- High-grade silica filler for rapid arc quenching.
- Rejection-style Class L design prevents incorrect replacement.
- RoHS compliant.
Advanced Protection for Industrial Power Distribution
The Mersen A4BQ900 is engineered to minimise the effects of severe overloads and short-circuit faults by limiting the current and energy reaching downstream electrical equipment. This helps reduce thermal and mechanical stress on switchgear, busbars, conductors and other critical system components.
Its integrated time-delay characteristic allows temporary motor and transformer inrush currents to pass without nuisance operation while maintaining dependable protection against sustained overloads and fault currents. This combination of current limitation and time-delay performance makes the A4BQ900 ideal for demanding industrial environments.
Typical Applications
- Service entrance equipment.
- Industrial switchgear and switchboards.
- Main electrical distribution systems.
- High-current feeder circuits.
- Large motor protection.
- Transformer protection.
- Circuit breaker back-up protection.
- UPS DC links and battery disconnect systems.
- Heavy industrial and commercial facilities.
