What is a single-line diagram (SLD) and what information does it convey?

What is a single-line diagram (SLD) and what information does it convey?

• A. A single-line diagram is a multi-line diagram of mechanical piping.
• B. A single-line diagram is a simplified unidirectional diagram showing connections, power sources, feeders, protective devices, and bus bars.
• C. A single-line diagram is a financial ledger of energy costs.
• D. A single-line diagram is a schematic of light fixtures only.

Answer: (B)

A single-line diagram is a simplified, unidirectional representation of an electrical power system. It uses a single conductor line to represent the three-phase circuit and shows how the system is connected from sources through feeders to loads, including the protective devices and bus bars that tie equipment together. This diagram communicates where power comes from, how it is distributed, what protection is in place, and how the bus bars interconnect, all in a form that makes analysis and coordination easier. It isn’t about mechanical piping, a financial ledger, or a schematic limited to lighting fixtures.

A single-line diagram is a simplified, unidirectional representation of an electrical power system. It uses a single conductor line to represent the three-phase circuit and shows how the system is connected from sources through feeders to loads, including the protective devices and bus bars that tie equipment together. This diagram communicates where power comes from, how it is distributed, what protection is in place, and how the bus bars interconnect, all in a form that makes analysis and coordination easier. It isn’t about mechanical piping, a financial ledger, or a schematic limited to lighting fixtures.