CMU702080

Eaton's CMU medium-voltage power fuses, part of the Cooper Power series, are expulsion-style, boric acid fuses engineered for protective switching on systems up to 38 kV. Available in three voltage classes-17 kV, 27 kV, and 38 kV-the CMU fuse line covers current ratings from 3 A to 200 A and includes three speed types: Standard ("E"), Fast ("K"), and Slow ("SE") curves for application flexibility. Designed as a one-piece, non-refillable solution, the CMU fuse delivers high interrupting performance (up to 14,000 A symmetrical) with lower arc energy and reduced exhaust gas compared to conventional cutout-style fuse tubes. The construction includes a boric acid liner, calibrated silver element, and an arcing rod mechanism that provides a controlled interruption and mild exhaust during fault conditions.

These fuses are suitable for a broad range of utility and industrial distribution systems and are commonly deployed in the protection of transformers, capacitor banks, switchgear, and feeder circuits. The CMU's high-speed operating characteristics ensure isolation of faulted circuits to minimize the extent of service interruptions. Their coordination capabilities and gradual time-current slope make them ideal for use as upstream protective devices. CMU units can be installed in both indoor and outdoor configurations using compatible end fittings, and they are engineered to meet multiple IEEE standards, assuring performance under demanding electrical fault conditions.

The operation of the CMU fuse is based on the deionizing action of boric acid, which vaporizes into water and boric anhydride to extinguish arcs at current zero. In the event of a fault, the arcing rod is propelled into the boric acid chamber, triggering arc elongation and extinction. Outdoor versions feature a dropout mechanism for visual fault indication, while indoor units are designed to minimize noise and exhaust contamination via a muffler attachment. End fittings are reusable if undamaged, and fuse replacement is easily managed with a hotstick tool. The CMU fuse design prioritizes dielectric integrity, transient recovery voltage resistance, and easy integration with existing mountings, making it a preferred solution for medium-voltage overcurrent protection.

The CMU702080 is a 80A, Class Rating K fuse. You can find the CMU702080 at Electrical.com, your reliable partner for Eaton and Cooper Bussman fuses. Our dedicated sales team is ready to assist with technical questions, product selection, and support.