Electrical Standard Symbols of Single Line Diagram

This article is about Electrical Standard Symbols related to topic of Single Line Diagrams of 480 Voltage system.

Electrical Standard Symbols of Single Line Diagram

In electrical engineering, single-line diagrams are commonly used to represent electrical power systems or circuits. These diagrams use standardized symbols to depict various components and connections within the system. Here are some of the standard symbols used in single-line diagrams:

1. Power Sources:

• Generator: Symbolized by a circle with a vertical line and a few horizontal lines inside to represent the internal workings of the generator.
• Battery: Depicted as two parallel lines, one longer than the other, with a plus sign (+) and a minus sign (-) to indicate the positive and negative terminals.

1. Transmission Lines:

• Transmission lines are typically represented by straight lines connecting different components in the diagram. Arrows may indicate the direction of power flow.

1. Transformers:

• Transformer: Represented by two overlapping circles with lines indicating the primary and secondary windings. Often labeled with the transformer’s kVA rating.
• Autotransformer: Similar to a transformer symbol but with a single circle instead of two separate circles.

1. Switchgear and Protection Devices:

• Circuit Breaker: Symbolized by a rectangle with a diagonal line inside, indicating the breaking of the circuit when tripped.
• Disconnect Switch: Depicted as an open rectangle.
• Fuse: Represented by a small circle with a line protruding from one side.

1. Loads:

• Motor: Usually shown as a circle with a letter “M” inside, representing the rotating motor shaft.
• Resistor: Shown as a zigzag line.
• Lamp: Represented by a circle with a cross inside.

1. Control Devices:

• Contactor: Symbolized by a rectangle with two semi-circles on either side.
• Relay: Typically shown as a rectangle with a diagonal line inside, similar to a circuit breaker but without the full rectangle.

These are just a few examples of the many symbols used in single-line diagrams. Each symbol helps convey important information about the components and their functions within the electrical system.

Electrical Standard Symbols Single Line Diagrams