Breaking strength is the maximum load a conductor or cable can withstand in tension before rupturing, typically measured in pounds (lbs) or kilograms (kgs).
In wire and cable design, breaking strength is a critical mechanical property that measures how much force a conductor can endure before it fractures. It is a key factor in assessing durability, reliability, and safety in commercial and industrial environments. Unlike electrical properties such as conductivity or resistance, breaking strength focuses on physical integrity under stress. Influencing factors include conductor material, strand count, diameter, and protective layers. Environmental exposure to heat, cold, or corrosion can also reduce performance over time. Testing involves applying increasing tensile load until failure, establishing safe handling limits during production, transportation, and use.
Breaking strength requirements are commonly guided by ASTM (American Society for Testing and Materials), IEC (International Electrotechnical Commission), and UL (Underwriters Laboratories).
The concept of breaking strength originated in metallurgy and materials science. In electrical cabling, its importance grew as larger-scale industrial and commercial systems demanded assurance of mechanical durability during installation and operation.