This lesson covers the knowledge, skills, and proper attitude in identifying, and analysing common electrical signs, symbols and data.
At the end of this lesson, you should be able to:
Cognitive Domain
Identify common electrical symbols, signs and data
Affective Domain
Determine electrical signs and symbols according to classification or as appropriate in drawing.
Psychomotor Domain
Draw and label appropriate electrical signs and symbols accordingly.
Electrical Symbols are small drawings or pictograms used to represent various electrical devices in a diagram or plan of an electrical circuit. These symbols are used in sketching schematic diagrams and electrical plans for numerous types of electrical works. Practically any electrical fixture found in a house has a symbol that coincides to said fixture on an electrical wiring diagram. These are very useful guide for an electrician or electrical contractor, thus, making the wiring easier to install as well.
A ground symbol (IEC symbol 5017) identifies a ground terminal. It can be used for a zero potential reference point from where current is measured. It is also for electrical shock protection.
There are a few different ground symbols. The one we're showing here is "Earth", but there's also a Chassis and Digital/Common ground with slight variations to this symbol.
A resistor reduces current flow. In a schematic, this is represented with a few zigzag squiggles. We're showing the US/Japan version of this symbol (IEEE). The UK uses a simple box over a straight line (IEC). There are also symbols for variable and adjustable resistors as well as thermal and preset resistors.
Disconnect the current when open. We're showing a simple SPST (single-pole single-throw) toggle switch, but there are variations for SPDT, pushbutton, dip, relay, and more. For a complete list of switch symbols, check out SmartDraw's electrical symbol library.
A capacitor symbol shows two terminals running into plates. The curved plate indicates that the capacitor is polarized. The curved side has lower voltage. A small plus sign can be added to the straight side indicated the positive pin.
A fuse protects electrical circuits by stopping the flow of current when the intensity of current exceeds a set value. It does this by melting a special wire.
Mark a device, rod, or wire designed to capture radio and electromagnetic waves into electrical signals and vice versa.
An inductor is also called a coil or reactor. The coils store energy in a magnetic field or flux. An inductor symbol looks like a series of looped coils.
A transformer is two or more coils coupled by magnetic induction. It helps keep the frequency and reduce tension in an AC circuit.
A motor is a device that can transform electric energy into mechanical energy.
Represent the power source for your electronics. This symbol represents a direct current (DC). To represent AC current, you'd replace the plus and minus sign with a wave.
Batteries are represented on a schematic with a pair of disproportionate, parallel lines. The number of lines indicates the number of series cells in the battery.
A diode only allows current to flow in one direction. It's always polarized with an anode (A, positive) and cathode side (C, negative).
A diode LED is a standard diode symbol with two small arrows showing the emission of light.
These 4 important safety signs can be broken into categories: Prohibition, Warning, Mandatory and Emergency.
These signs should be used for “Do Not” commands. For example – to indicate that smoking is not allowed in a particular area. In the workplace they should be used to reinforce instructions prohibiting dangerous activities.
Signs prohibiting an activity appear as a circular red band with a single diagonal cross line descending from left to right at a 45 degree angle. The background should be solid white with the imagery indicating the nature of the command in black.
A sign giving warning of a hazard or danger (e.g. “Danger: High Voltage”)
These signs should be used to make people aware of a nearby danger.
For example, a flammable liquid store.
`These health and safety signs are required by the Health and Safety (Safety Signs and Signals) Regulations 1996 and in specific cases by the Dangerous Substances (Notification and Marking of Sites) Regulations 1990.
Signs warning of a particular hazard appear as a black band in the shape of an equilateral triangle. The background within the band should be yellow with the imagery indicating the type of hazard in black, positioned centrally on the sign.
A safety sign prescribing specific behaviour (e.g. “Personal Protective Equipment Must Be Worn”)
These signs should be used to indicate actions that must be carried out in order to comply with statutory requirements. For example, self-closing fire doors that must be kept closed to comply with the fire risk assessment should be labeled with “FIRE DOOR KEEP SHUT” signs. An area of a construction site where hard hats should be worn should also have appropriate signs at the entry points.
It should be noted that the Health and Safety (Safety Signs and Signals) Regulations 1996 do not apply to mandatory fire instructions but do apply to health and safety mandatory signs where imagery is required. The minimum regulatory requirement is for the sign to display appropriate imagery.
There are no pictograms for fire safety instruction signs and although mandatory in the UK through inclusion in the requirements of workplace fire assessments, such signs are not considered as health and safety signs within these Regulations. Thus the familiar white on blue fire safety mandatory signs using text only will remain in place and will not have to be changed.
Fire instruction notices, are notices which list actions that occupants must carry out in the event of a fire are, by convention, written as white text on blue background but not in the circular format.
The colors are used to convey the mandatory nature of the instructions but because of the amount of text normally needed, a rectangular format is used.
The general mandatory sign of a white exclamation mark on a blue circle may be used in conjunction with a fire instructions notice.
Signs indicating mandatory requirements consist of a blue circle with the pictogram or text in white positioned centrally.
An effective way of displaying these important documents is to install a Module and Shadow Board Solution.
A sign giving information on emergency exits, first aid, or rescue facilities (e.g. “Emergency Exit”)
These information signs should be used to indicate escape routes, emergency exits and first aid equipment.
Safe condition signs appear as a green rectangle or square with the imagery or text in white positioned centrally. In the same way as for mandatory signs some UK fire safety signs in this category are not required by the Health and Safety (Safety Signs and Signals) Regulations 1996.
For example “PUSH BAR TO OPEN” is not required to comply and there is no imagery with that meaning.
Red
Prohibition sign
Dangerous behaviour; stop; shutdown; evacuate
Yellow / Amber
Warning sign
Be careful; take precautions; examine
Blue
Mandatory sign
Specific behaviour or action; wear protective equipment
Green
Emergency escape / First-aid sign
Doors; exits; escape routes; equipment and facilities
Your power tool with its manual may contain "WARNING ICONS" (a picture symbol intended to alert you to, and/or to instruct you how to avoid a potentially hazardous condition). Knowing and understanding these symbols will help you operate your tool better and more safely.
Electrical signs and stickers alert students, workers, and visitors to electrical hazards in the area. Alerting workers to high voltage areas, electrical hazards, power lines and other electrical equipment in the area, can help prevent fires and injuries. Proper electrical signs can inform workers of the dangers in the area.
https://www.smartdraw.com/circuit-diagram/electrical-symbols.htm
https://www.reconelectrical.co.uk/image/data/pdfs/Electrical%20Symbols%20Guide.pdf
https://www.rapidtables.com/electric/electrical_symbols.html
https://gltnhs-tle.weebly.com/lesson-33.html
https://www.beaverswood.co.uk/what-are-the-4-types-of-safety-signs/