The FNQ-R-4 is a LIMITRON Class CC current-limiting, time-delay fuse designed for advanced protection in electrical circuits. It is rated for 600Vac operation with a 4-ampere current rating and features a 200kA interrupting rating (RMS symmetrical) that complies with NEC Section 110.9 for large capacity systems. The fuse provides 10X better current limitation compared to standard fuses, helping prevent equipment damage caused by short-circuit events, and offers significantly more time-delay than the UL minimum value of 12 seconds at 200% for Class CC fuses. With dimensions of 1.5 inches (38.1mm) length and 0.41 inches (10.3mm) diameter, it is a rejection-type fuse that fits both standard and rejection-style holders. The FNQ-R-4 is ideal for critical industrial and commercial applications including branch circuits, line protection, small control transformers, and industrial control systems where specific current limitation requirements and equipment protection are essential.