Meaning
Power transmission systems utilize flat copper or aluminum bars insulated and pressed together within a metal housing to move high currents. The sandwich bus duct design eliminates the chimney effect found in air-insulated types by providing a direct thermal path to the outer casing. Compact construction results in lower voltage drop and better mechanical strength during fault conditions.
Specification of this equipment occurs for heavy industrial loads where space is at a premium.
Heat Dissipation
Direct contact between the conductors and the enclosure allows for cooling through conduction. Because a sandwich bus duct lacks internal air pockets, it maintains a lower operating temperature than traditional cable-in-conduit installations.
Space Efficiency
Compact dimensions allow for high-capacity power runs in tight ceiling voids or riser shafts. A sandwich bus duct carries more amperage per square inch of cross-section than separated busbar configurations. Space savings make it suitable for high-density environments like high-rise buildings.
Magnetic Induction
Close spacing between phases leads to the cancellation of electromagnetic fields. Cancellation benefits make the sandwich bus duct ideal for environments where electromagnetic interference must be kept to a minimum near sensitive electronics. Proper phasing during installation is required to ensure the cancellation effect is achieved.
