The final protection points between an RPP or busway and the IT load have to fit into tight spaces without becoming the weak link in the short-circuit study. Eaton’s Bussmann series CUBEFuse and next-generation Compact Circuit Protector (CCP2) address that requirement by separating two functions: the CUBEFuse provides overcurrent protection, while the CCP2 provides a UL 98 branch-circuit disconnect and an enclosure for the fuse.

That distinction matters. A correctly selected combination can deliver high interrupting capability, current limitation, load isolation, and controlled flexibility without forcing a complete disconnect replacement every time a branch rating changes.

CUBEFuse: The Protective Element

The Bussmann series Low-Peak CUBEFuse is a UL Class CF current-limiting fuse with Class J time-delay performance. Current product data lists ratings from 1 A through 400 A, with up to a 300 kA interrupting rating at 600 Vac. The time-delay TCF design is available in indicating and non-indicating versions; the indicating version provides local open-fuse status to support faster troubleshooting.

Current limitation reduces peak current and let-through energy during many short circuits, which can help limit thermal and mechanical stress on downstream equipment. The fuse’s compact, blade-on-back form factor also supports finger-safe installations, although final finger-safe status depends on the complete installed assembly and the specified shrouds or accessories.

CCP2 and CCP2B: The Disconnect and Rejection System

The current CCP2 family supersedes the legacy CCP referenced in older data center literature. DIN-rail and panel-mounted CCP2 configurations are available for CUBEFuse applications, while the bolt-mounted CCP2B is used in the Quik-Spec Coordination Panelboard (QSCP). The disconnect is horsepower rated, available in one-, two-, and three-pole versions, and designed so an oversized fuse cannot be installed in a lower-rated switch.

A CCP2 accepts a CUBEFuse with an ampere rating equal to or below the disconnect rating within the product’s defined range. For example, a 60 A CCP2 can accept a 15 A, 35 A, or 60 A CUBEFuse. This does not make every change automatically acceptable—the conductor, cable whip, connector, load, equipment listing, and coordination study must all support the new rating—but it can eliminate an unnecessary switch replacement.

Why the Combination Fits Data Center Distribution

• High fault-duty margin: up to 300 kA fuse interrupting rating helps avoid a low-IR protective device at the end of a high-fault-current distribution path.

• Compact branch isolation: the disconnect and fuse can be placed close to the protected load without the footprint of many high-IR breaker solutions.

• Selective-coordination options: time-delay CUBEFuse coordinates readily with Bussmann Low-Peak fuses using published ratios, while mixed fuse families are checked against dedicated tables.

• Faster fault recovery: replacing an opened fuse installs a new factory-calibrated protective element; indicating versions and optional monitoring accessories can shorten fault location time.

• Controlled adaptability: the switch’s ampacity-rejection design prevents overfusing while allowing approved lower-rated fuses in the same disconnect.

Selection Checks Before Specification

• Confirm system voltage, AC/DC duty, number of poles, load characteristics, and whether time-delay or fast-acting protection is required.

• Verify the protective device interrupting rating and the SCCR of the complete assembly—not just the fuse rating—against available fault current.

• Check conductor ampacity, termination temperature ratings, cable-whip rating, connector rating, and the upstream equipment rating.

• Use current selective-coordination tables for every upstream and downstream protective-device pair.

• Specify approved accessories, open-fuse indication or remote monitoring, lockout/tagout provisions, spare-fuse strategy, and qualified-person work procedures.

Conclusion

CUBEFuse + CCP2 is strongest when it is specified as an engineered branch-protection system, not simply as a compact fuse holder. The combination brings high interrupting rating, current limitation, branch isolation, ampacity rejection, and practical reconfiguration into one platform. For data centers with dense racks and changing IT loads, that is a credible way to improve protection without sacrificing serviceability.

Models Mentioned

Sources

• Eaton Bussmann Series — Low-Peak Time-Delay CUBEFuse, Data Sheet No. 9000

• Eaton Bussmann Series — Fast-Acting CUBEFuse, Data Sheet No. 2147

• Eaton Bussmann Series — Compact Circuit Protector CCP2, Data Sheet No. 10801

• Eaton Bussmann Series — Compact Circuit Protector Base CCP2B, Data Sheet No. 1161