Fuses with Both 420V AC and DC Ratings in 5x20mm Package

Littelfuse, Inc. has introduced the 487 Series Fuse, the first fast-acting fuse from its 5x20mm fuse family with both 420Vac and 420Vdc ratings. In contrast with existing fuse solutions that cannot meet high-voltage and short-circuit test requirements, the 487 Series protects telecom power supply units and datacenter server power applications where a high-voltage dc interrupting rating is required. This compact ceramic body fuse is designed to ensure the best coordination between a power supply unit (PSU) and an electrical circuit breaker panel during short-circuit and over-current faults. The air circuit breaker trips before the fuse opens when the circuit is exposed to a short-circuit condition. When installed in a PSU, the 487 Series fuse opens faster than the circuit breaker in an electrical panel, removes the problematic PSU from the branch circuit, and keeps the branch circuit live without cutoff.

The 487 Series’ 420Vac characteristics make it well suited for high-energy applications like 3-phase power supplies, inverters, and ballasts. Its 420Vdc characteristics make it an optimal choice for a high-voltage dc power grid in datacenters, telecom, and intelligent commercial buildings.

“The new 487 Series Fuse offers an added reliability assurance for telecom power supplies because the fuse opens quickly and safely,” said Roger Huang, product manager for the 487 Series product line. “Its compact 5x20mm footprint saves space on the printed circuit board, which is especially important in high-power applications.”

The 487 Series Fuse offers these key benefits: Lower interrupting rating ( I2t) and faster tripping; this ensures the short-circuit and over-current fault in the PSU is protected because the 487 Series fuse in the electrical panel opens rather than the circuit breaker, which would cause an power outage in the entire branch circuit. Current ratings as high as 16A in a 5x20mm footprint, which saves space on the printed circuit board. The 487 Series Fuse is available in quantities of 1,000 (bulk packaging) in either cartridge or axial-leaded versions.