Overview
The Bussmann NO.663 fuse reducer is an industrial electrical accessory designed to enable the installation of lower-amperage Class R fuses into larger-capacity fuse blocks. Rated for 600V service, this reducer bridges the gap between 30A fuses and 60A fuse block openings, making it essential for electrical panel downsizing and code-compliant protective device installation. The product is supplied as a pair and features robust construction to maintain reliable electrical and mechanical contact under industrial conditions.
Key Features
- Allows 30A Class R fuses to fit securely in 60A fuse block openings
- 600V rated for industrial and commercial electrical systems
- Non-indicating design suitable for most panel types including dead-front enclosures
- Maintains strong mechanical and electrical contact through precision engineering
- Supplied as a pair (two reducers per box) for dual-circuit protection
Technical Specifications
- Amperage Range: 60A to 30A
- Voltage Rating: 600V AC
- Fuse Class: Class R
- Quantity Per Box: 2 reducers
- Dimensions (Each Unit): 2.7 in L × 1.5 in W × 1.9 in H
- Indicator Type: Non-Indicating
- Manufacturer: Bussmann (Eaton)
- Compatible Panel Types: Standard, switches, dead-front enclosures
Typical Applications
- Industrial control panel downsizing and load redistribution
- Machine tool and automation equipment electrical protection
- Commercial HVAC and refrigeration fuse block adaptation
- Code-compliant protective device installation where fuse block openings exceed load requirements
- Retrofit applications in existing electrical systems
Compatibility & Replacements
Compatible With
- 60A fuse block openings in electrical panels and switches
- Class R fuses rated 1–30A (FRN-R, LPN-R, FRS-R, LPS-R, KTN-R, KTS-R)
- Standard panel designs and dead-front enclosures
- 600V AC electrical systems
Replaces / Drop-In Replacement For
- Eaton Bussmann NO.663-R
- Littelfuse LRU 663R
- Ferraz/Mersen R636
Works With
- 600V AC industrial electrical distribution systems
- Class R fuse family across all amperage ratings up to 30A
- Standard NEC electrical installation practices and requirements
- Both single and multi-phase power configurations
