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The NRS300 – Gould 300A 600V Class K5 One-Time Fuse offers exceptional protection for your electrical systems. Designed for high-performance applications, this fuse reliably interrupts overload currents to safeguard equipment from damage. Ideal for critical systems and heavy-duty use, it ensures safety and efficiency in your circuits when it’s needed most.
Class K5 and Class RK5 fuses share the same 300A/600V ratings, but Class RK5 fuses have a rejection feature (a notch or ring on the ferrule) that prevents them from being installed in non-rejection (Class H/K) holders. The Gould NRS300 is a non-rejection Class K5 fuse, so it fits standard Class H/K holders. If your holder is a rejection-type, you'll need a Class RK5 fuse instead. Contact us if you're unsure which class your holder accepts.
The Gould NRS series is considered a legacy/obsolete product line following Gould's acquisition by Ferraz Shawmut (now Mersen). Northern Breaker Group specialises in hard-to-find and obsolete electrical components and maintains stock of legacy fuses for maintenance and replacement applications. Contact our Calgary, Edmonton, or Vancouver counter for current availability and to request a quote.
One-time (non-renewable) fuses like the NRS300 do not have a visual indicator window. The most reliable way to confirm a blown fuse is to use a multimeter set to continuity or resistance mode — a blown fuse will show no continuity. Always de-energise and lock out/tag out (LOTO) the circuit before testing or replacing any fuse, in accordance with CSA Z462 electrical safety standards.
