Why Choose the Mersen A4BQ400 Class L Time-Delay Fuse?
The Mersen A4BQ400 is a reliable Class L time-delay fuse designed to protect industrial and commercial electrical systems against damaging overloads and short-circuit currents. As part of the established Mersen Amp-Trap 2000® A4BQ series, it is suitable for service entrance equipment, switchgear, feeder circuits and other power distribution applications requiring dependable high-capacity circuit protection.
The A4BQ400 combines advanced current-limiting performance with a time-delay operating characteristic. This allows temporary inrush currents generated by motors, transformers and other inductive equipment to pass without unnecessary fuse operation while still providing rapid protection during serious fault conditions.
With a rated current of 400 A and voltage ratings of up to 600 V AC and 500 V DC, the A4BQ400 is engineered for demanding electrical installations. Its robust blade-style construction supports secure mounting in compatible Class L fuse holders and equipment.
Key Advantages
- Dependable Class L time-delay fuse for industrial power protection.
- 400 A current rating suitable for high-capacity circuits.
- 600 V AC and 500 V DC voltage ratings.
- Advanced Amp-Trap 2000® current-limiting technology.
- Time-delay characteristic accommodates temporary equipment inrush currents.
- High interrupting capacity provides effective protection during severe faults.
Key Features
- Mersen Amp-Trap 2000® A4BQ series.
- 400 A rated current.
- 600 V AC rated voltage.
- 500 V DC rated voltage.
- Class L time-delay fuse.
- Current-limiting design reduces damaging fault energy.
- 4-second minimum time delay at 500% of rated current.
- Blade terminals for secure installation.
- Suitable for service entrance and feeder circuit protection.
Reliable Protection for Electrical Distribution Systems
The Mersen A4BQ400 helps protect conductors, switchgear and connected equipment by limiting the current and energy that pass through a circuit during a short circuit. This current-limiting performance reduces thermal and mechanical stress on downstream components, helping improve electrical safety and system reliability.
Its time-delay characteristic makes the fuse particularly suitable for circuits containing motors, transformers and other loads that generate temporary start-up currents. The fuse tolerates normal inrush conditions while responding effectively to sustained overloads and dangerous fault currents.
Typical Applications
- Service entrance equipment.
- Industrial switchgear and switchboards.
- Electrical feeder circuits.
- Motor control centres.
- Transformer protection systems.
- Commercial power distribution panels.
- Manufacturing and processing equipment.
