What are the characteristics of cable branch boxes and how to choose them?

What is a cable branch box?

With the advancement of cable distribution networks, cable branch boxes are being used to connect multiple cables when small, independent loads are concentrated. Because branch boxes cannot directly access individual cables and only serve as cable branches, their primary function is to split or transfer cables.

Cable branching: Multiple small cables on a long line often result in cable waste. Therefore, a large trunk cable is often used to connect the line to the load. Near the load, a cable branch box is used to split the trunk cable into several smaller cables, which are then connected to the load. This wiring method is widely used in urban power grids to power streetlights and other small consumers.

Cable transfer: If the cable length on a long line does not meet the line requirements, cable connectors or cable transfer boxes must be used. Typically, intermediate cable connectors are used for short distances. However, for longer lines (over 1000 meters), if multiple intermediate connectors are present, a cable branch box may be used to transfer the cables for safety reasons.

Cable Branch Box Selection

♦Air-insulated type, primarily made of heat-shrinkable material. This product is an early product and has been phased out.

♦Cable branch boxes with rubber-plastic jackets as the primary material for protection. Over long-term operation, these boxes are prone to internal interface separation and cracking of exposed terminals, compromising insulation and sealing. Therefore, the development of this product is limited.

♦ Cable branch boxes with sealed cable connectors, primarily made of EPDM. This material is relatively hard, and EPDM is flammable, making it prone to electrical creepage, arcing, and burning. Furthermore, its moisture-proof, waterproof, and aging resistance are weak, making it insufficient for long-term maintenance-free operation. EPDM is toxic and poses environmental risks.

♦ Cable branch boxes with live pluggable cable connectors. my country's power supply system is powered by three-phase transformers. Simultaneous plugging and unplugging while powered on is impossible. Doing so would cause a significant shift in the neutral point, resulting in a short-term two-phase power supply, causing severe power outages and unnecessary economic losses to the power supply and equipment.

♦ Flood-resistant cable branch box with silicone rubber as the primary material for cable connectors. This material is soft, highly elastic, high-density, and fully insulated. It offers excellent sealing properties, is moisture-proof, waterproof, age-resistant, flame-retardant, corona-resistant, and maintains long-term maintenance-free operation. Because the silicone rubber and cable form an interference fit, radial contraction is highly uniform, preventing internal interface separation due to thermal expansion and contraction, which could lead to internal creepage breakdown. It also exerts sustained radial pressure on the cable, ensuring a tight and reliable internal bond. Silicone rubber is inherently non-toxic, making it environmentally friendly.

♦ Cable branch box with SF6 load switch disconnector. Because this product performs the functions of a ring main unit (RMU) at a lower price, it plays an important role in replacing switchyards outdoors. It facilitates maintenance, testing, and overhaul of branch lines, reducing economic losses from power outages. Its advantages are particularly evident in line corridors and where building distribution rooms is difficult.

Cabinet Features

♦ Effectively prevents condensation and frost.

♦ Excellent outdoor protection rating, up to IP54.

♦ Modular construction, lightweight, and easy to install.

♦ Streamlined design, resists advertising and meets environmental standards.

♦ 180° door opening, tool-free door and panel replacement.

♦ Stable overall structure, three-point locking, and padlockable.

♦ Matte finish, harmonious and aesthetically pleasing, eliminates light pollution.

Pre-Operation Precautions

♦ Before operating the cable branch box, ensure that the grounding wires of each branch cable are securely connected to the grounding terminals on the box. The box housing must also be directly connected to the ground grid or have a clear grounding point.

♦ After installation, the cable branch box must be tested along with the cables and components in accordance with the relevant test standards and conditions.

Shaanxi Huadian Cable Branch Box has high quality and service. We look forward to your call!

Email:pannie@hdswitchgear.com.

Whatsapp/Wechat:+8618789455087