This is the second part of Electrical Symbols ( Electrical Symbols Part 1 )
These are remaining symbols for electrical circuit design of electrical drawing using CAD software. This standards help others to understand what is on electrical schematic, including electrical components and wires
The most popular standard for electrical CAD symbols is international IEC ( IEC 60617 or DIN EN 60617-2 to DIN EN 60617-12). In US we have NEMA(NEMA ICS 19-2002, ANSI Y32.2/IEEE 315/315 A, CSA Z99)
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Below is table with circuit symbols is based upon the following international, UK and United States specifications:
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Description of symbol
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IEC UK, Europe and International
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NEMA United States
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Control devices
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NO Standard Push-Button
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NC Standard Push-Button
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Limit Switch or Position Switch
(Normally Open)
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Limit Switch or Position Switch
(Normally Closed)
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Proximity Switch NC
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Proximity Switch NO
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Pressure Switch ( here Normally opened )
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Float Switch
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Shielding
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Earth, Ground, general symbols
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Protective earth Protective ground
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Connector with plug and socket
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 or |
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Isolating point, lug, closed
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Electrical Symbols
Now example of electrical passive components and control circuit devices
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Description of symbols
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IEC UK, Europe and International
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NEMA United States
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|---|---|---|---|---|
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Passive components and control circuit devices
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Resistor
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 or |
 or |
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Resistor with fixed tappings
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 or |
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Variable resistor
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Adjustable resistor
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Potentiometer
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Winding, inductance
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 or  |
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Capacitor
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 or  |
 or  |
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Variable capacitor
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| Klaxon or horn |  |
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| Buzzers |  or  |
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| Indication light |  |
 or  |
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| Visual indicator |  |
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Electrical symbols – contacts and driving elements
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Description of symbols
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IEC UK, Europe and International
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NEMA United States
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|---|---|---|---|---|
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Driving elements
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Manual operation
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Operation by pushing
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Operation by pulling
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Operation by key
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Operation by turning
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Operation by rollerss or sensors
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Stored energy mechanism
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Switch mechanism with mechanical release
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| Operated by motor |  |
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| Emergency switch (mushroom) |  |
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| Operated by electromagnetic overcurrent protection |  |
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| Operated by thermal overcurrent protection |  |
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| Control by fluid level |  |
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| Electromagnetic operation |  |
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Contacts
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N/O contact
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 or |
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N/C contact
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 or |
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Changeover contact with interruption
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 or |
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Early-make N/O contact of a contact assembly
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 TC |
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Late-break N/C contact of a contact assembly
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 TO |
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N/O contact, delayed when closing
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 or |
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N/C contact, delayed when reclosing
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 or  |
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