NRN50 – GOULD 50A 250V CLASS H ONE-TIME FUSE

Yes — Class RK1 and RK5 fuses (e.g., a 50A/250V LPN-RK-50SP) will fit most existing Class H holders, provided the holder does not have a Class R rejection feature blocking the reverse. Upgrading to Class R gives you a significantly higher 200kA interrupting rating, which is often preferred for modern Canadian electrical code compliance. We can help you select a compatible upgrade.

The Gould (now Ferraz Shawmut / Mersen) NRN50 is considered a legacy Class H fuse but remains available through specialty distributors like Northern Breaker Group. Direct equivalents include the Bussmann NON-50 and Ferraz Shawmut NRN50 — all are interchangeable Class H one-time fuses at 50A/250V. Contact us for current availability at our Calgary, Edmonton, or Vancouver counters.

A one-time (non-renewable) fuse like the NRN50 must be completely replaced after it operates — the fuse element cannot be refitted. A renewable Class H fuse uses a replaceable link inside a reusable fuse body. For most modern industrial and commercial applications, one-time fuses are preferred for reliability and consistency, and are widely accepted under the Canadian Electrical Code (CEC).