Dimensions and weight of cables

A comprehensive guide to understanding fuse classification according to IEC 60269-1. "The abbreviation is made up of two letters: the first, lowercase, identifies the current interruption field (g or a); the second, uppercase, indicates the category of use." — According to IEC 60269-1 What Are Fuse Application Categories? Fuse application categories define: The type of circuit the fuse protects Its performance under fault conditions Whether it can interrupt short-circuit currents Compatibility with circuit breakers and other protective devices These categories ensure safe operation and coordination in power distribution systems. Standard Classification System (IEC 60269-1) Two-Letter Code Format First letter (lowercase): Current interruption capability Second letter (uppercase): Application category First Letter: Interruption Field Letter Meaning `g` General purpose – capable of interrupting all fault currents up to its rated breaking capacity. `a` Limited application – designed for overload protection only, not full short-circuit interruption. Second Letter: Category of Use Letter Application `G` General-purpose fuse – suitable for protecting conductors and cables against overcurrents and short circuits. `M` Motor protection – designed for motors, provides thermal overload protection and limited short-circuit protection. `L` Lighting circuits – used in lighting installations, often with lower breaking capacity. `T` Time-delayed (slow-blow) fuses – for equipment with high inrush currents (e.g., transformers, heaters). `R` Restricted use – specific applications requiring special characteristics. Common Fuse Types & Their Uses Code Full Name Typical Applications `gG` General-purpose fuse Main circuits, distribution boards, branch circuits `gM` Motor protection fuse Motors, pumps, compressors `aM` Limited motor protection Small motors where full short-circuit interruption is not required `gL` Lighting fuse Lighting circuits, domestic installations `gT` Time-delay fuse Transformers, heaters, starters `aR` Restricted use fuse Specialized industrial equipment Why This Matters Using the wrong fuse category can lead to: Failure to clear faults → fire risk Unnecessary tripping → downtime Incompatibility with circuit breakers Violation of safety standards (IEC, NEC) Always select the correct fuse based on: Circuit type (motor, lighting, general) Load characteristics (inrush current) Required breaking capacity Coordination with upstream protection

The standard resistor values are organised into a set of series of values known as the E-series .The different values are spaced such that the top of the tolerance band of one value and the bottom of the tolerance band of the next one do not overlap.

The characteristics and certification of the fuses are usually defined on the fuse label. UL and CSA are the most common fuse certifications used in North America.

Appliance classes (also known as protection classes) specify measures to prevent dangerous contact voltages on unenergized parts, such as the metallic casing, of an electronic device. In the electrical appliance manufacturing industry, the following appliance classes are defined in IEC 61140 and used to differentiate between the protective-earth connection requirements of devices.