A power busbar is essentially a system that encapsulates several conductors within a metal casing through a safe and rational structure, forming an electrically continuous power distribution and transmission system. Standard busbars are generally categorized into two types: dense insulation and air insulation. The air-insulated type features a simple structure, high current transmission capacity, compact design, and good heat dissipation. Both types offer strong overload capabilities, easy threading, and minimal space occupancy. Cables are divided into single-core and multi-core types. Single-core cables are mainly made of various insulating materials. The multi-strand copper wires serve as conductors for phase current, wrapped within the insulating layer. Multi-core cables are a complete cable formed by twisting multiple insulated conductors together and sheathing them. The number of insulated conductors in a single power cable is typically 1, 2, 3, 4, 5, 4+1, 3+2, etc. The main advantages of cables are flexible selection and strong environmental adaptability, although they also have inherent limitations. Below, a comparison of the performance of busbars and cables will be made from several key aspects.
The low-voltage cable has a cross-sectional area of 1000mm2 and a rated current of 1600A. Such cables, due to their large size and weight, are rarely used in actual engineering. The commonly used cables in engineering are 400mm2 and below, and multiple cables are needed for simultaneous power supply. Busbars have a rated current of up to 6300A, their strong current-carrying capacity is simply unparalleled by cables.
The overload capacity of cables and busbars depends on the working temperature of the insulation material used. The working temperature of the busbar insulation material is 105°C, and radiation cross-linked flame-retardant coated tapes (PER) and radiation cross-linked polyolefin heat-shrinkable tubes with a working temperature above 140°C have been developed. The normal working temperature of the insulation material currently used in cables is generally 90°C and 105°C, while the working temperature of irradiated cross-linked cables is 125°C. Therefore, the overload capacity of busbars is significantly greater than that of cables.
The installation of power busbars typically employs the plug-in method. The so-called plug-in power busbar connects the main power point to the branch using a plug-in mechanism, with a plug-in box every few meters, making the connection very convenient. The cables need to be spliced on-site, which has lower reliability. Even pre-manufactured branch cables have their drawbacks. One significant drawback of branch cables is the need to customize branch connection equipment to the factory, usually using an open "C" type clamp. Over time, whether this clamp can maintain sufficient clamping force is also a concern. Additionally, the branch heads of branch cables are expensive, so the application of pre-manufactured branch cables is not widespread. When installing branch cables, the power to the floor needs to be cut off, whereas installing busbars requires no power cut-off; simply remove the busbar plug box when the busbar is unloaded. However, cutting off the branch power while the pre-manufactured branch cable is live is extremely dangerous.
Busbars and cables play a major role in low-voltage power distribution systems, with varying advantages and disadvantages in different applications within the distribution system. Traditional busbars are facing challenges from cables, especially branch cables. Years of practical experience have shown that both have their own strengths in product performance, application fields, and economic costs, and a simple conclusion cannot be drawn. This article provides a multifaceted comparison of cables and busbars, which can serve as a reference for actual work.
The busbar trunking insulation material exceeds the super support, with a working temperature above 100°C. The busbar trunking products use DuPont polyester film, with an insulation temperature grade of 130°C. Additionally, the busbar trunking shell is made of metal, which is flame-retardant and has good fire resistance properties.
