I. Busbar trunking and the performance characteristics of the cable

1. Current-carrying capacity: Currently, cables can only achieve a maximum cross-sectional area of 1000 mm² and a rated current of 1600 A. However, due to their large size and heavy weight, such large-diameter cables are rarely used in engineering applications. In practice, cables with a cross-sectional area of 400 mm² or less are generally employed. Standard cable-based power distribution typically requires multiple cables to supply power simultaneously, while busbar trunking systems have a maximum Rated current It can handle up to 6,300 A, a current-carrying capacity that cables simply cannot match.

2. Overload Capacity: The overload capacity of busbar trunking systems primarily depends on the operating temperature of the insulation materials used. Insulation materials with an operating temperature of 105°C are currently employed for supporting busbar trunking systems. Recently, radiation-crosslinked insulation materials with an operating temperature of 140°C have been developed, offering enhanced flame retardancy. Wrapping tape (PER) and radiation-crosslinked polycarbonate heat-shrink tubing. The normal operating temperature of insulation materials used in cables is typically 95°C or 105°C; therefore, the overload capacity of busbar trunking systems is significantly higher than that of cables.

3. Heat Dissipation Performance: The insulation materials of cables—both core insulation and sheath insulation—serve dual functions as both electrical insulators and thermal insulators. Therefore, when power cables are installed in cable trays, a maximum of two layers is permitted. This limitation is based on considerations of heat dissipation and the use of busbar trunking systems, which rely on air for cooling. Conductive Heat Dissipation , heat is dissipated through the tightly contacted metal casing. Consequently, its thermal performance is comparable to that of a cable, as evidenced by the cable’s thermal performance.

4. Service Life: Busbar trunking systems have a service life of 50 years, while cables typically last 15–20 years. Clearly, busbar trunking systems offer a significantly longer service life than cables.

5. Maintenance: Busbar trunking systems require virtually no maintenance. Routine maintenance typically involves measuring the temperature rise of the enclosure and the core bolts, as well as the temperature rise at the inlet box joints. If the core bolts are Grade 4.8, they must be periodically tightened. However, when using Grade 8.8 high-strength bolts, periodic tightening is not required. In contrast, cables are prone to wear, aging, and have a relatively short service life, so they require regular inspection, maintenance, and even replacement.

II. Construction and Installation

Cable laying is flexible and convenient along the route. However, in practice, cables are typically supported by cable trays and laid in a single continuous run to complete the routing. Consequently, cable installation must be carried out in stages. In contrast, busbar trunking systems require specialized installation techniques, but can be installed in one go by following the manufacturer’s standard installation procedures. Moreover, busbar trunking systems have a compact structure and occupy relatively little space, making them easy to integrate into spaces where piping and cabling are already arranged, and simplifying installation. For low-current circuits below 400 A, however, because smaller cable cross-sections are selected and fewer cables are required, cable laying offers greater flexibility.

III. Power Supply System Configuration

Busbar power supply systems typically feature a main trunk line routed from the distribution center, providing decentralized and flexible power delivery; in contrast, cable-based power supply is hampered by the difficulty of tapping off branches, Current-carrying capacity limitations such as small scale and difficulties in decentralized control. Typically, Peer-to-peer Power supply, especially for high-rise buildings, benefits greatly from the use of busway systems compared with traditional cable-based solutions. As illustrated in the figure above, the right side shows the conventional wired power distribution method: each floor requires its own dedicated cabling, resulting in a large number of cables. Such dense wiring not only leads to poor heat dissipation and inefficient space utilization but also presents challenges such as limited available space, difficulty in fault diagnosis, and cumbersome maintenance. In contrast, the left side depicts busway-based power distribution: by implementing a centralized busway system and equipping each floor with a plug-in distribution box of appropriate capacity for load sharing, power can be efficiently supplied. This approach offers exceptional flexibility in tap-off arrangements, with each branch circuit protected by its own plug-in box. Shunt and capacitive transformation. Upon comparison, it is evident that the latter is safer, simpler, and more reliable than the former.

IV. System Architecture

1. Busbar trunking distribution: compact structure and neat layout

2. Cable distribution: numerous cables and complex structure