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Longitudinal Water Blocking vs. Lateral Water Blocking?
A longitudinally water blocking cable is designed with a barrier to prevent the spread of moisture along its length. Longitudinal water blocking stops water from migrating along the cable's core, typically between the conductor strands, insulation layers, or metallic screens. Lateral water blocking ensures that water cannot penetrate the cable in the event that the sheathing is pierced or damaged. Radial water blocking prevents water from penetrating the cable's outer sheath or insulation layers, thereby stopping it from entering the cable structure entirely.
Longitudinal water blocking can be achieved through various methods, including the application of water-blocking tapes and powders. These are frequently located on either side of a metallic screen and conductor. Lateral water blocking is typically accomplished by applying a layer of aluminum/polyester tape to the underside of the outer sheath.
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How do you calculate the minimum bending radius of cables?
The bend radius refers to the curved shape in which an electrical cable can be bent or curved without sustaining damage. To determine the minimum bend radius for cables, apply the following formula: Minimum Bend Radius = Cable Outer Diameter×Cable Multiplier. For example, if the outer diameter of a cable is 20mm, its minimum bending radius would be 20mm×6 = 120mm. Conversely, if an armored cable has an outer diameter of 30mm, its minimum bending radius would be 30mm×12 = 360mm.
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Is a flame-retardant cable also fire resistant?
No. A flame-retardant cable is not the same as a fire-resistant cable. A flame-retardant cable is designed to restrict the spread of fire by inhibiting combustion. Fire-resistant cables, on the other hand, maintain circuit integrity and continue to function for a specified time under defined fire conditions.
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Flame Retardant Cables VS Fire Resistant Cables?
Both types of cables are crucial in enhancing the likelihood of escape and survival in the event of a fire and are often confused with one another. However, there is a fundamental distinction between flame retardant cables and fire resistant cables.
Flame retardant cables are engineered to inhibit the spread of fire to adjacent areas. On the other hand, fire resistant cables are specifically designed to preserve circuit integrity and ensure functionality during a fire, under specified conditions, aiding both evacuees and firefighters.