How much tension is acceptable for optical cable

The Maximum Allowable Tension (MAT) is the highest tension an optical cable can safely withstand under design weather conditions without causing permanent fiber strain or additional attenuation.Definition and PurposeMAT represents the maximum tension applied to an optical cable under theoretical worst-case environmental conditions, such as wind, ice, and temperature extremes, while ensuring the fiber strain remains within safe limits (≤0.05% for stranded cables and ≤0.1% for central tube cables) without additional attenuation . It is a critical parameter for aerial installations, guiding engineers in determining safe sag, span lengths, and installation tension .Relationship with Rated Tensile Strength (RTS)The Rated Tensile Strength (RTS), also known as ultimate tensile strength, is the maximum load a cable can withstand before breaking . MAT is typically set at about 40% of RTS, providing a safety margin to account for aging, creep, installation stress, and environmental variability . This ensures that the cable remains operational over its expected lifespan without catastrophic failure.Calculation ConsiderationsMAT is calculated based on the total mechanical load per unit length, which includes:Cable weightIce accumulationWind pressureHorizontal and vertical components of tension The calculation ensures that the cable's axial tensile force does not exceed the MAT at any point along the span . For ADSS cables, MAT is essential for determining sag-tension-span relationships, ensuring the cable is neither too tight (risking breakage) nor too loose (causing excessive sag), .Practical GuidelinesFor stranded loose tube or ribbon cables, typical maximum pulling tension during installation is around 600 lbf (2,700 N), but the exact value should be verified from the manufacturer's specification sheet .MAT is used to calculate allowable span lengths and installation tension, taking into account environmental loads and desired sag .Annual average stress (EDS), usually 16–25% of RTS, represents the long-term operational tension under average conditions, ensuring minimal fiber strain and stable performance .Key TakeawaysMAT ensures structural reliability and fiber integrity under extreme conditions.It provides a safety buffer relative to RTS to prevent cable failure.Proper MAT calculation is essential for aerial cable design, including sag, span, and installation tension optimization.Always consult the specific cable specification sheet for exact MAT values, as they vary by cable type, construction, and environmental design criteria .