TR40R – GOULD 40A 250V CLASS RK5 TIME DELAY FUSE

Class RK5 and Class RK1 fuses share the same physical dimensions and fit the same Class R holders, but they differ in their current-limiting performance — Class RK1 has stricter let-through limits. The Gould TR40R is rated Class RK5, which provides reliable time-delay overcurrent protection suitable for motor circuits and general loads. If your application specifically requires Class RK1 performance, a different fuse will be needed. If you're unsure which class is specified for your equipment, check the nameplate or contact us and we'll help you confirm.

The Gould TR-series fuse line has transitioned through several brand changes (Gould → Ferraz Shawmut → Mersen), and some catalogue numbers may be harder to find through standard channels. Northern Breaker Group specializes in obsolete and hard-to-find electrical components — if the TR40R is no longer in active production, we can help source original stock or identify a direct, spec-matched replacement. Contact one of our Calgary, Edmonton, or Vancouver counters for availability.

Motors draw a significant inrush current at startup — often 6 to 8 times their full-load current — for a brief period. A fast-acting fuse would blow during this harmless inrush, causing nuisance trips. The TR40R's time-delay characteristic allows the motor to start normally while still providing fast, reliable protection against sustained overloads and short circuits. This makes it the correct choice for motor branch circuits and motor control applications per Canadian Electrical Code (CEC) requirements.