A Guide to Electrical Symbols for Construction Drawings

Symbols for Electrical Construction Drawings

Electrical construction drawings are diagrams that show the layout and design of electrical systems in buildings and structures. They include information such as the location, type, size, and connection of electrical components and devices. Electrical construction drawings are essential for planning, installing, maintaining, and troubleshooting electrical systems.

Symbols For Electrical Construction Drawings.pdf

One of the most important aspects of electrical construction drawings is the use of symbols. Symbols are graphical representations of electrical elements that simplify and standardize the communication of information. In this article, we will explain what electrical symbols are, why they are important, how to read them, and what types of symbols are commonly used in electrical construction drawings. We will also discuss the standards that regulate the use of electrical symbols in different countries and regions.

Introduction

What are electrical symbols?

Electrical symbols are used to represent electrical components in diagrams. These symbols are standardized by organizations such as the National Electrical Manufacturer Association (NEMA) and the International Electrical Coalition (IEC) to make drawings simpler to read and communicate. It is important to study the symbol name and what it represents to interpret an electrical symbol.

There are international standards for electrical symbols, such as IEC 60617 and IEC 61131-3. Graphical symbols are used to identify the position and type of electrical element in circuit diagrams and schematics. Electrical symbols are also used on home electrical wiring plans to show the location, control point, and type of electrical devices required at those locations. Basic electrical symbols include earth electrode, cell, battery, and resistor.

Why are electrical symbols important?

Electrical symbols are important because they help to:

• Convey information clearly and accurately.

• Reduce errors and misunderstandings.

• Save time and space.

• Facilitate design and analysis.

• Ensure compliance with codes and regulations.

By using electrical symbols, engineers and electricians can communicate complex information in a simple and concise way. Electrical symbols also help to avoid confusion and ambiguity that may arise from using words or descriptions. Moreover, electrical symbols can save time and space by eliminating the need for lengthy explanations or detailed drawings. Electrical symbols also enable designers and analysts to visualize and evaluate the performance and functionality of electrical systems. Finally, electrical symbols help to ensure compliance with codes and regulations that govern the safety and quality of electrical installations.

How to read electrical symbols?

To read electrical symbols, you need to follow these steps:

• Identify the type of diagram you are looking at. There are different types of diagrams that use electrical symbols, such as circuit diagrams, wiring diagrams, schematic diagrams, etc. Each type of diagram has its own purpose and conventions.

• Refer to the legend or key that explains the meaning of each symbol. The legend or key is usually located on the same page or sheet as the diagram. It may also be found in a separate document or manual. The legend or key lists the name, description, and reference number of each symbol.

• Trace the connections and paths of the electrical elements. Electrical symbols are usually connected by lines that represent wires or conductors. The lines may be straight, curved, dashed, or dotted, depending on the type of connection or circuit. The lines may also have labels or numbers that indicate the wire size, color, or function.

• Understand the logic and operation of the electrical system. Electrical symbols are arranged in a logical and functional way to show how the electrical system works. You need to understand the basic principles of electricity, such as voltage, current, resistance, power, etc., to interpret the symbols correctly. You also need to know the common rules and conventions that apply to electrical diagrams, such as the direction of current flow, the polarity of terminals, the orientation of switches, etc.

Types of Electrical Symbols

Power Symbols

Power symbols are used to represent the sources and distribution of electrical power in a system. They include symbols for outlets, switches, panels, junction boxes, etc. Power symbols are usually drawn on a floor plan or a layout diagram to show the location and type of power devices in a building or structure.

Examples of power symbols

Symbol

Name

Description

Duplex Outlet

A standard wall outlet that provides two receptacles for plugging in electrical devices.

Weatherproof Duplex Outlet

A wall outlet that is designed to withstand outdoor conditions and has a protective cover.

Ground Fault Circuit Interrupt Duplex Outlet

A wall outlet that has a built-in device that detects and interrupts ground faults, which are abnormal currents that can cause electric shocks or fires.

Duplex Outlet - One Receptacle Controlled by Switch

A wall outlet that has one receptacle that is controlled by a switch and another receptacle that is always on.

Double Duplex Outlet (aka Quad Outlet)

A wall outlet that provides four receptacles for plugging in electrical devices.

Switch

A device that controls the flow of electricity to a circuit or a device by opening or closing the contacts.

3-Way Switch

A switch that allows controlling a circuit or a device from two different locations.

Switch with Built-In Dimmer

A switch that allows adjusting the brightness of a light source by varying the voltage or current.

Power Panel

A metal enclosure that contains circuit breakers or fuses that protect and distribute electrical power to different circuits or devices.

Lighting Symbols

Lighting symbols are used to represent the sources and fixtures of artificial lighting in a system. They include symbols for recessed lights, surface mounted lights, track lights, wall mounted lights, etc. Lighting symbols are usually drawn on a ceiling plan or a reflected ceiling plan to show the location and type of lighting devices in a room or space.

Examples of lighting symbols

Symbol

Name

Description

2x2 Recessed Light

A light fixture that is mounted in a ceiling opening and has a 2x2 foot dimension.

2x2 Recessed Light on Emergency Branch

A light fixture that is mounted in a ceiling opening and has a 2x2 foot dimension and is connected to an emergency power source.

2x4 Recessed Light

A light fixture that is mounted in a ceiling opening and has a 2x4 foot dimension.

2x4 Recessed Light on Emergency Branch

A light fixture that is mounted in a ceiling opening and has a 2x4 foot dimension and is connected to an emergency power source.

Recessed Linear Light

A light fixture that is mounted in a ceiling opening and has a linear shape.

Recessed Linear Light on Emergency Branch

A light fixture that is mounted in a ceiling opening and has a linear shape and is connected to an emergency power source.

Surface Mounted Utility Light

A light fixture that is attached to the surface of a ceiling or a wall and has a simple or utilitarian design.

Track Lighting

A light fixture that consists of multiple adjustable heads attached to a track that can be mounted on a ceiling or a wall.

Recessed Can Light

A light fixture that is mounted in a ceiling opening and has a cylindrical shape.

Wall Mounted Light

A light fixture that is attached to the surface of a wall and can have various shapes and styles.

Recessed Wall Wash Light

A light fixture that is mounted in a ceiling opening and has a directional beam that illuminates a wall or a vertical surface.

Fire Alarm Symbols

Fire alarm symbols are used to represent the devices and components of a fire alarm system in a building or structure. They include symbols for fire alarm pull boxes, strobes, horns, smoke detectors, key boxes, exit signs, emergency lights, etc. Fire alarm symbols are usually drawn on a floor plan or a layout diagram to show the location and type of fire alarm devices in a building or structure.

Examples of fire alarm symbols

Symbol

Name

Description

Fire Alarm Pull Box

A device that allows a person to manually activate the fire alarm system by pulling a lever or a handle.

Fire Alarm Strobe and Horn Combination

A device that produces both visual and audible signals to alert people of a fire emergency.

Smoke Detector

A device that detects the presence of smoke and activates the fire alarm system.

Fire Department Key Box

A device that contains a set of keys that allow the fire department to access the building or structure in case of an emergency.

Ceiling Mounted Exit Sign

A device that displays the word "EXIT" and an arrow that indicates the direction of egress. It is mounted on the ceiling and is illuminated by an internal or external source.

Wall Mounted Exit Sign

A device that displays the word "EXIT" and an arrow that indicates the direction of egress. It is mounted on the wall and is illuminated by an internal or external source.

Battery Powered Emergency Light

A device that provides illumination in case of a power outage. It is powered by a battery and has one or more lamps that can be adjusted to direct the light.

Security Symbols

Security symbols are used to represent the devices and components of a security system in a building or structure. They include symbols for panic buttons, card readers, magnetic door locks, electric door latches, electric door strikes, security cameras, etc. Security symbols are usually drawn on a floor plan or a layout diagram to show the location and type of security devices in a building or structure.

Examples of security symbols

Symbol

Name

Description

Panic Button or Distress Button

A device that allows a person to send an emergency signal to the security system by pressing a button.

Card Reader

A device that reads a card that contains a code or a chip that identifies the user and grants or denies access to a door or a gate.

Magnetic Door Lock

A device that locks or unlocks a door by using an electromagnet that attracts or releases a metal plate.

Electric Door Latch

A device that latches or unlatches a door by using an electric motor that rotates a bolt or a hook.

Electric Door Strike

A device that allows or prevents a door from opening by using an electric solenoid that moves a metal piece that interacts with the door latch.

Security Camera

A device that captures and transmits video images of a specific area for surveillance or monitoring purposes.

Communications Symbols

Communications symbols are used to represent the devices and components of a communications system in a building or structure. They include symbols for telephone jacks, data jacks, combination jacks, speakers, etc. Communications symbols are usually drawn on a floor plan or a layout diagram to show the location and type of communications devices in a building or structure.

Examples of communications symbols

Symbol

Name

Description

Telephone Jack

A device that provides a connection for a telephone line.

Data Jack

A device that provides a connection for a data network.

Data Jack for Wall Mounted Item

A device that provides a connection for a data network for an item that is mounted on the wall, such as a TV or a monitor.

Combination Telephone and Data Jack

A device that provides both a connection for a telephone line and a connection for a data network.

Ceiling Mounted Speaker

A device that produces sound from an audio source and is mounted on the ceiling.

Standards for Electrical Symbols

International standards

International standards are developed by organizations that represent the interests of various countries and regions. They aim to harmonize the use of electrical symbols across different markets and industries. Some of the most widely used international standards for electrical symbols are:

• IEC 60617: Graphical symbols for diagrams. This standard covers the general principles, classifications, and graphical symbols for electrical diagrams in various fields, such as power generation, transmission, distribution, conversion, measurement, control, communication, etc.

IEC 61131-3: Programmable controllers. This standard covers the programming languages, syntax, semantics, and presentation for programmable controllers, which are devices that control industrial processes and machines. It includes graphical symbols f