Why ​wire and cable insulation will be broken down?

Insulation breakdown is one of the main quality accidents of cables and one of the main fire causes of cable fires. What are the reasons for the breakdown of wire and cable insulation?

1. Mechanical damage. Wires and cables were injured by heavy objects, and the cables were accidentally injured by the excavator. The cables were bent over during laying and the insulation was injured. The cables were severely squeezed during shipment and the insulation and protective layer were damaged. The direct buried cables suffered excessive tension due to the sinking of the bottom layer. And so on, all lead to damage to the wire and cable insulation and even break the cables. We should avoid mechanical damage to the cable, use overhead cables. If the cables are laid along the wall, they should be covered. The burial should be clearly marked, and timely stop taking soil near the cable.

2. Improper construction will also cause damage to the wire and cable insulation. Due to poor construction methods and poor quality of materials used, the cable head and the weak links in the middle failed, resulting in the breakdown of the insulation layer. To prevent this phenomenon, the installation quality of the cable head should be improved. During the production and installation of the cable head, the insulating bag should be tight and no gaps should appear. Before epoxy resin and quartz powder, strict drying treatment should be carried out to prevent air bubbles and moisture from entering the cable head, and strengthen the insulation treatment at the edge of the insulation.

3. The insulation is damp. Due to the poor construction technology of the wire and cable head, moisture can penetrate into the cable, or the inner sheath of the cable is damaged and moisture can enter. Lead-covered cables are laid near the source of the earthquake, causing fatigue cracks due to long-term vibration. The wire and cable insulation is corroded and voids are produced. Due to poor manufacturing quality, there are small holes or cracks in the lead package. In view of these situations, the maintenance of the outer layer of the cable should be strengthened, and a layer of asphalt should be applied to the outer protective layer regularly.

4. Overvoltage. The wire and cable insulation is broken down due to atmospheric overvoltage or internal overvoltage, especially the internal overvoltage of the system will cause multiple cables to be broken down at the same time. In this regard, lightning arresters should be installed to improve the technological level of automatic protection of the system.

These are the reasons that lead to the breakdown of wires and cables, and we should take protective measures. JZD cable is a manufacturer with more than 20 years of production experience. We have rich experience in wire and cable. Welcome to contact us for more information.