A terminal block designed for a rigid Class 1 conductor might not clamp down securely on a flexible Class 6 conductor unless the wire is "tinned" (coated in solder) or fitted with a ferrule (a metal sleeve). Conversely, trying to screw a thick solid wire into a terminal designed for flexible cords can damage the terminal or the wire. IEC 60228 allows connector manufacturers to specify exactly which "Class" of conductor their equipment accepts.
The standard divides conductors into four distinct classes based on their flexibility and construction: Typical Use Solid Fixed installations; rigid and single-wire. Class 2 Stranded
Before the widespread adoption of standards like IEC 60228, defining a wire was surprisingly ambiguous. A manufacturer might sell a "2.5 mm²" cable based on the overall diameter including insulation, while a customer expected that measurement to apply only to the copper conductor. iec 60228
The standard establishes unified global technical requirements for conductors used in fixed installations and flexible applications. It does apply to conductors for telecommunications purposes. Materials: Covers copper, aluminum, and aluminum alloy.
In the complex world of electrical engineering, the flashiest components often get the most attention—smart sensors, high-speed processors, and advanced power electronics. However, the reliability of any electrical system ultimately depends on its most fundamental component: the wire connecting everything together. A terminal block designed for a rigid Class
IEC 60228 is the unsung hero of electrical safety. It moves the definition of a wire from a vague physical description to a precise electrical performance standard. By standardizing resistance values and categorizing flexibility, it ensures that whether a cable is powering a subway train or a smartphone, the conductor inside is safe, reliable, and fit for purpose.
IEC 60228 categorizes conductors into four classes based on their flexibility and construction: Description & Application The standard divides conductors into four distinct classes
It does not specify insulation; it focuses strictly on the conductor , establishing maximum allowable D.C. resistance at 20°C for various materials and sizes.
(Note: Classes 3 and 4 were historically present but are largely obsolete or reserved for specific legacy applications in modern revisions.)
Would you like a comparison table with AWG or guidance on how to select the correct conductor class for a specific application?
Furthermore, a solid wire behaves differently than a stranded wire. A solid wire has a smaller diameter for the same cross-sectional area, but it is stiff. A stranded wire (made of many smaller wires twisted together) is flexible but has a larger overall diameter due to the gaps between strands.