Description
Overview
The Eaton Bussmann 500FMM is a 500 A high speed semiconductor protection fuse from the Bussmann FMM series, rated 690 V AC and 450 V DC with a breaking capacity of 200 kA. Built to the Double Barrel BS88 format and conforming to BS88 Part 4 and IEC 60269-4, this Class aR fuse is engineered to protect sensitive power semiconductor devices — including thyristors, IGBTs, diodes, and SCRs — from damaging fault currents before the device can be harmed. Its combination of high interrupt rating, fast clearing speed, and broad application compatibility makes it a preferred choice for panel builders and OEMs across India working on industrial drives and power conversion equipment.
Key Features
- High Speed Current Limiting Action — Clears fault currents faster than semiconductor device withstand times, preventing costly device damage
- 200 kA Breaking Capacity — Suitable for high fault-level industrial installations including main distribution and converter feeds
- 690 V AC / 450 V DC Dual Voltage Rating — Covers both AC supply and DC bus protection in a single fuse type
- Class aR Rating — Purpose-designed for semiconductor protection, not general-purpose use, ensuring selectivity in the protection scheme
- Double Barrel BS88 Form Factor — Compact, robust construction compatible with standard BS88 fuse holders and switch-disconnectors
- IEC 60269-4 Compliant — Tested and rated to the international standard governing semiconductor protection fuses
- IEC Rated and UL Recognized — Accepted across global and Indian projects with dual certification coverage
- CE Marked and RoHS Compliant — Meets European directives; suitable for export equipment and environmentally sensitive installations
- Bussmann FMM Series — Proven platform with broad current range and holder ecosystem for panel design flexibility
Technical Specifications
| Specification | Value |
|---|---|
| Catalog Number | 500FMM |
| Series | Bussmann FMM |
| Amperage Rating | 500 A |
| Rated Voltage AC | 690 V |
| Rated Voltage DC | 450 V |
| Breaking Capacity | 200 kA |
| Fuse Class | Class aR |
| Fuse Type | High Speed British Standard Double Barrel |
| Standard | BS88 Part 4, IEC 60269-4 |
| Certifications | IEC Rated, UL Recognized |
| Compliances | CE Marked, RoHS Compliant |
| Application | Semiconductor protection, DC drives, VFDs, power converters, rectifiers, soft starters, thyristor stacks, DC common bus |
Applications & Selection Guide
The 500FMM is the go-to fuse for protecting power semiconductors in high-current industrial applications. It is commonly installed on the AC supply side or DC bus of variable frequency drives (VFDs), soft starters, thyristor rectifiers, and IGBT-based power converters where standard gG or gR fuses are too slow to protect the switching devices. The Class aR designation means this fuse operates only in the high fault current region — it must always be used in combination with a correctly rated upstream general-purpose fuse or circuit breaker for overload protection.
In the Indian industrial context, the 500FMM sees widespread use in steel rolling mills, paper and pulp plants, chemical process drives, traction equipment, UPS and battery charger systems, and renewable energy inverter assemblies. Panel builders in Coimbatore and across Tamil Nadu frequently specify this fuse in MCC panels, drive panels, and rectifier cubicles where reliable semiconductor protection is a design requirement rather than an option.
When selecting this fuse, verify that the rated voltage matches or exceeds the system voltage on both AC and DC sides, and that the 200 kA breaking capacity is adequate for the prospective short circuit current at the point of installation. Consult the Eaton Bussmann FMM fuse holder and BS88 carrier range for compatible mounting hardware. For application-specific sizing assistance, contact Shansen Enterprises — our technical team supports panel builders and project engineers across India.
Why Buy from Shansen Enterprises?
- Authorized Eaton Channel Partner in Coimbatore — 100% genuine products with full manufacturer backing
- 100% genuine Eaton Bussmann products supplied with warranty and traceability documentation
- Pan-India delivery — dispatching to Chennai, Mumbai, Pune, Hyderabad, Bengaluru, Delhi, and all major industrial hubs
- WhatsApp technical support — get application guidance, cross-reference help, and order status updates instantly
- Bulk pricing and priority availability for panel builders, OEMs, and EPC contractors
Compatible Products & Accessories
- Eaton Bussmann FMM Series Fuse Holders and BS88 Carriers (matching 500 A frame)
- Eaton Bussmann FMM Series fuses in other current ratings (lower ampere steps for system design)
- Eaton BS88 Switch-Disconnectors compatible with Double Barrel fuse links
- Upstream general-purpose BS88 gG fuses for overload backup protection
- Eaton Bussmann Semiconductor Fuse Blocks and DIN Rail Adapters
- Eaton Motor Protection and Drive Control products for complete drive panel solutions
Frequently Asked Questions
What does Class aR mean for the 500FMM fuse?
Class aR (accompanying Range) designates a fuse that is rated to protect semiconductors only within a specific high-current range — it does not provide overload protection at low overcurrent levels. The 500FMM must always be paired with an upstream general-purpose fuse (Class gG or equivalent) or a circuit breaker that handles overload and low-level fault currents. This selectivity ensures the aR fuse clears only during faults severe enough to damage semiconductor devices, while the upstream device handles routine overcurrents.
Can the 500FMM be used on both AC and DC circuits?
Yes. The Eaton Bussmann 500FMM carries a dual voltage rating — 690 V AC and 450 V DC — making it suitable for AC supply-side protection as well as DC bus protection in drive and converter systems. Always verify the actual system voltage does not exceed the rated voltage for the applicable circuit type. For DC common bus applications above 450 V DC, a different fuse rating or type would be required.
Is the 500FMM suitable for protecting VFDs and soft starters in Indian industrial installations?
Yes. The 500FMM is widely used in India for protecting VFDs, soft starters, DC drives, and rectifier bridges in industrial facilities including textile mills, cement plants, steel works, chemical plants, and water treatment stations. Its 690 V AC rating covers standard Indian HT and LT distribution voltages for drive applications, and its 200 kA breaking capacity meets the fault level requirements of most industrial distribution systems. Always verify the drive manufacturer’s fuse recommendation for the specific drive rating.
What is the breaking capacity of the 500FMM and why does it matter?
The 500FMM has a breaking capacity of 200 kA, which represents the maximum fault current the fuse can safely interrupt without rupturing or causing an arc flash hazard. In high-power industrial installations — particularly those close to transformer secondaries or with large transformer ratings — prospective short circuit currents can reach tens of kiloamperes. A 200 kA rated fuse ensures safe operation even in the most fault-current-intensive environments found in Indian industrial plants.
Which fuse holders and carriers are compatible with the Eaton Bussmann 500FMM?
The 500FMM uses a Double Barrel BS88 form factor and is compatible with Eaton Bussmann FMM series fuse holders and standard BS88 Part 4 carriers rated for 500 A. When selecting a holder, confirm that the holder’s current rating, voltage rating, and mechanical dimensions match the 500FMM fuse link. Contact Shansen Enterprises for holder cross-reference assistance — our team can help identify the correct carrier and mounting hardware for your panel design.
How do I order the Eaton Bussmann 500FMM from Shansen Enterprises?
You can request a quote for the Eaton Bussmann 500FMM directly from Shansen Enterprises via WhatsApp or email using the contact buttons on this page. Share your required quantity, delivery location, and any project-specific requirements. As an authorized Eaton Channel Partner based in Coimbatore, we supply genuine 500FMM fuses with full warranty and can arrange pan-India delivery to your site or warehouse. Bulk orders and repeat supply contracts are welcome — ask about our pricing for panel builders and OEMs.
