Branch circuit protection on a 20A rated power strip is not an National Electrical Code1 (NEC) requirement. Server Technology has both 20A Inlet rated CDU products with and without branch circuit protection. The presence of Bussmann SC-20 fuses on 20A units, even though not required, allows for selective coordination with short-circuit faults. Fuses react fast enough to halt a short-circuit fault nearest the fault while also reducing let-through to upstream and parallel branch gear.
1 "National Electrical Code" and "NEC" are registered trademarks of the NFPA. While the NEC is not itself a U.S. law, NEC use is commonly mandated by state or local law, as well as in many jurisdictions outside of the United States. The NEC codifies the requirements for safe electrical installations into a single, standardized source.