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10 Common Electrical Symbols and Meanings

These symbols might look like nonsense to the layman, but they provide a ton of information to the EE

Basic electrical schematic diagrams

An electrical schematic diagram might look like a nonsensical drawing to the layman, but to the electrical engineer, it’s a high-level documentation that provides a ton of insight and instruction.

An electrical schematic diagram.

An electrical schematic diagram.

The difference between an electrical schematic and a block / layout diagram is that the former shows the actual electrical connections. If it’s just a visual meant to show how the wires and components are laid out and connected, it’s referred to as the latter. Each symbol in an electrical schematic has its purpose and is used to replace the need for what would otherwise be text-heavy descriptions.

A good example is the electrical symbol below. It might look fairly simple to most, but it actually stands for “three-phase, open delta, grounded at common point”.

Electrical symbol meaning, three-phase, open delta, grounded at common point.

Can you imagine what an electrical schematic might look like if there were descriptions like this all throughout the diagram? To circumvent this would-be headache, electrical engineers are carefully trained to recognize these symbols, identify their meaning, and understand their relationship to other nearby symbols.

What are the most common electrical symbols? Today, there are literally dozens of electrical symbols used — the following is a collection of some of the more commonly used symbols found on electrical schematic diagrams, ranging from the simpler of symbols to those that are slightly more complicated in design and definition.

Electrical Symbols and Their Meanings

Rectifier
Rectifier electrical symbol.

Phase Meter
Phase meter electrical symbol.

240V Outlet
240v outlet electrical symbol.

Flow Switch
Flow switch electrical symbol.

NOR Gate
NOR gate electrical symbol.

Continuously Adjustable Resistor
Continuously adjustable resistor electrical symbol.

Normally open foot switch
Normally open foot switch electrical symbol.

Timer off delay, normally open
Timer off delay, normally open electrical symbol.

Shielded transformer with magnetic core
Shielded transformer with magnetic core electrical symbol.

Thermally operated relay with normally open contacts
Thermally operated relay with normally open contacts electrical symbol.

3-pole circuit breaker with magnetic overload protection
3-pole circuit breaker with magnetic overload protection electrical symbol.

How often do you come across these symbols in the electrical schematics you see day-to-day?

Related articles:

  1. List of Symbols and Abbreviations in Electronics
  2. Basic Schematic Symbols
  3. Do you know your ground symbols?

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