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Electrical referenceMy legend
Drawing conventions

IEC symbol forms

149 explicitly identified drawing forms. Each record names its convention evidence and explains the meaning and drafting context. The broader symbol collection also includes general concepts relevant to multiple conventions.

What this collection means

IEC-oriented forms here are identified from public convention references. IEC 60617 is the standards database for graphical symbols used in diagrams. Vendor block identifiers are search aliases, not IEC symbol identity numbers.

A related representation expresses a comparable function in the cited context. It does not establish identical graphic construction, terminal numbering or compliance. These original educational illustrations are not a reproduced or certified standards library.

IEC 60617 scope and access

Explicitly identified forms

Related general concepts

These 224 records explain functions relevant to this reference family. They do not assign a single convention to their educational illustration.

Current transformerA current-measurement transformer used with metering and protection equipment.Voltage transformerA transformer providing a voltage signal for metering or protection.Circuit breakerA switching device that can interrupt a circuit, with specified fault-interruption capability.DisconnectorA switching device providing an electrical isolation function.Load-break switchA switch with a specified capability to make and break normal load current.Earthing switchA switch used to connect an identified circuit section to earth.FuseAn overcurrent protective element that interrupts a circuit by melting its fuse link.BusbarA common conductive connection distributing power to connected circuits.Normally open contactA contact shown open in the normal state defined for its device.Normally closed contactA contact shown closed in the normal state defined for its device.Changeover contactA contact arrangement switching a common connection between two contact paths.Relay coilThe operating element associated with a relay and its separately drawn contacts.ContactorAn electrically operated switching device commonly used for repeated switching duties.Normally open pushbuttonA pushbutton contact normally shown open before actuation.Normally closed pushbuttonA pushbutton contact normally shown closed before actuation.Emergency-stop operatorAn identified emergency-stop operator and its documented contact arrangement.Selector switchAn operator switch selecting between documented control positions.Indicator lampA visual indicator associated with a documented control or equipment condition.Terminal connectionAn identified electrical connection point linking schematic and wiring information.CT test terminalA current-transformer terminal arrangement providing documented test and shorting facilities.Power transformerEquipment transferring electrical power between winding circuits.GeneratorAn electrical generating source represented in a power-system drawing.Three-phase motorAn electrical motor load connected to its switching and protective equipment.PLC input / outputA controller interface point connecting field signals to an identified module channel.CapacitorA capacitive component or bank identified with its circuit function and ratings.ResistorA resistive component with its value and purpose documented separately.Protective earthAn identified connection serving the protective earthing function.BatteryAn electrochemical electrical source or storage element represented in a circuit.Power converter / inverterAn identified interface converting electrical power between documented circuit forms.Single-pole circuit breakerA circuit breaker interrupts one pole of a circuit.Thermal circuit breakerA thermal circuit breaker uses a temperature-responsive trip mechanism to detect sustained overload.Thermal-magnetic circuit breakerA thermal-magnetic breaker combines overload response with a magnetic response to high current.Current-limiting circuit breakerA current-limiting breaker reduces the fault-current peak and energy passed to downstream equipment within its documented operating range.Residual-current circuit breakerAn RCCB operates on residual current and has no integral overcurrent protection.Residual-current breaker with overcurrent protectionAn RCBO combines residual-current operation with overcurrent protection in one device.Circuit breaker with undervoltage releaseA breaker undervoltage release changes the breaker operating condition when its control voltage falls below the specified range.Circuit breaker with electronic trip unitA breaker electronic trip unit measures current and applies configured protection functions.Miniature circuit breakerAn MCB is a compact low-voltage circuit breaker commonly used for final circuits and auxiliary supplies.Moulded-case circuit breakerAn MCCB is a low-voltage circuit breaker built in a moulded insulating case.Air circuit breakerAn ACB is a low-voltage circuit breaker using air as its interrupting medium.Additional circuit-breaker poleAn additional pole is a separately drawn part of a multipole circuit breaker.Switch-disconnectorA switch-disconnector combines operational switching with an isolation function.Lockable disconnectorA lockable disconnector has a mechanism that can retain the isolation position under a specified locking arrangement.Lockable switch-disconnectorA lockable switch-disconnector combines an isolation-capable switching device with a documented locking provision.Three-position disconnectorA three-position disconnector selects between two paths and an intermediate position.Semiconductor power switchA semiconductor power switch controls a power path electronically.Unidirectional semiconductor power switchA unidirectional semiconductor switch has a specified direction for its power conduction or control behaviour.Two-pole power switchA two-pole power switch operates two circuit conductors through a common device.Disconnector auxiliary NO contactA normally-open disconnector auxiliary contact provides a separate indication or permissive circuit associated with the disconnector mechanism.Disconnector auxiliary NC contactA normally-closed disconnector auxiliary contact is closed in the documented unactuated reference state.Fused switchA fused switch combines a switching function with fuse protection.Fuse-switchA fuse-switch uses a fuse-link or fuse carrier as part of its moving switching contact system.Additional fused-switch poleAn additional fused-switch pole represents another conductor of a common multipole device.General-purpose full-range fuseA gG fuse-link provides full-range overcurrent protection for general applications within its documented ratings.Motor short-circuit fuseAn aM fuse-link is a partial-range fuse used for motor-circuit short-circuit protection.Motor full-range fuseA gM fuse-link is a motor-circuit fuse with a characteristic chosen for starting and fault conditions.Current transformer with two secondariesA CT with two secondary windings supplies two documented secondary circuits.Tapped-secondary current transformerA tapped CT secondary provides alternative documented transformation ratios through different terminal combinations.Current transformer with primary conductor indicationThis CT representation explicitly identifies the primary conductor passing through the measurement location.Core-balance current transformerA core-balance CT measures residual current from the net magnetic effect of conductors passing through its window.Residual connection of phase CTsA residual CT connection combines secondary currents from phase CTs to obtain a residual-current input.Single-phase two-winding transformerA single-phase two-winding transformer transfers energy between separate primary and secondary windings.Electrostatically screened transformerA screened transformer includes a documented screen between windings.Three-winding transformerA three-winding transformer couples three windings through its magnetic system.Adjustable-ratio transformerAn adjustable-ratio transformer includes a documented means of varying its voltage ratio.Single-phase autotransformerA single-phase autotransformer uses a winding portion shared electrically by its input and output circuits.Three-phase star autotransformerA three-phase star-connected autotransformer has electrically shared winding portions arranged in a three-phase star connection.Star-delta transformerA star-delta transformer connects one winding set in star and the other in delta.Delta-star transformerA delta-star transformer provides a delta-connected winding and a star-connected winding.Delta-delta transformerA delta-delta transformer uses delta-connected windings on both sides.Star-star transformerA star-star transformer has star-connected windings on both sides.Star-zigzag transformerA star-zigzag transformer combines a star-connected winding set with a zigzag-connected set.Star-star-delta three-winding transformerA star-star-delta transformer includes two star-connected winding sets and a delta tertiary winding.Delta winding connectionA delta winding connects three phase windings in a closed loop.Open-delta winding connectionAn open-delta arrangement uses an incomplete delta connection for a specified transformer or measurement purpose.Star winding connectionA star winding joins one end of each phase winding at a common point.Star winding with accessible neutralAn accessible-neutral star winding brings the common star point to a documented terminal.Zigzag winding connectionA zigzag winding interconnects portions of phase windings in a specified arrangement.Mechanically latched relay coilA mechanically latched relay retains a documented state after the initiating electrical command is removed.Relay reset coilA reset coil releases or changes the retained state of its associated latching relay.Solid-state relayA solid-state relay switches an output through semiconductor circuitry in response to a control input.Polarised relay coilA polarised relay has operation or a specified response that depends on the documented electrical polarity.AC relay coilAn AC relay coil is intended for a specified alternating-current control supply.High-speed relayA high-speed relay has a documented operating response intended for duties where relay timing matters.Measuring relayA measuring relay responds to a measured electrical quantity and issues an output according to its configuration.Relay coil with diode suppressionA relay with diode suppression includes a diode associated with its coil to limit the transient on de-energisation.Relay coil with diode and LEDA relay assembly with diode and LED combines coil transient suppression and a visible energisation indicator.Relay coil with capacitor suppressionA relay with a capacitor suppression element includes a documented capacitive network associated with the coil.Relay coil with RC suppressionA relay RC suppression network uses resistance and capacitance associated with the coil circuit.Counter relay with manual resetA manually reset counter relay records qualifying events and retains a count until the documented reset action.Counter relay with electrical resetAn electrically reset counter relay has a separate reset command or documented electronic reset mechanism.Non-resettable counter relayA non-resettable counter records events without a normal user reset function.On-delay timer relayAn on-delay timer postpones a specified output transition after its timing condition becomes active.Off-delay timer relayAn off-delay timer holds a specified output condition for a documented period after its initiating condition is removed.On-delay normally-open contactAn on-delay NO contact changes from its unoperated open state only after the associated timing condition has persisted for the documented delay.On-delay normally-closed contactAn on-delay NC contact opens after the associated timing condition has persisted for its documented interval.Off-delay normally-open contactAn off-delay NO contact retains the documented operated state for an interval after the timer trigger is removed.Off-delay normally-closed contactAn off-delay NC contact returns to its documented normally-closed state after the delay following removal of the timing trigger.Maintained normally-open contactA maintained NO contact retains the actuated closed position according to its mechanism or control arrangement.Maintained normally-closed contactA maintained NC contact retains its actuated position until the documented return action occurs.Manually unlatched NO contactA manually unlatched NO contact includes a mechanical retaining action released by a documented manual operation.Manually unlatched NC contactA manually unlatched NC contact has a mechanical retained state and a documented manual release.Early-make normally-open contactAn early-make NO contact closes earlier in the mechanism sequence than specified associated contacts.Late-make normally-open contactA late-make NO contact closes later in a documented mechanism sequence than associated contacts.Early-break normally-closed contactAn early-break NC contact opens earlier in a documented mechanical sequence than associated contacts.Late-break normally-closed contactA late-break NC contact opens later in the documented operating sequence than specified associated contacts.Make-before-break changeover contactA make-before-break changeover contact establishes the next path before releasing the previous path during its documented transfer.Motor overload trip NC contactAn overload trip NC contact opens on the documented overload relay operation.Motor overload alarm NO contactAn overload alarm NO contact closes on the documented overload relay operation.Illuminated normally-open pushbuttonAn illuminated NO pushbutton combines a manual normally-open contact function with an indication lamp.Illuminated normally-closed pushbuttonAn illuminated NC pushbutton combines a normally-closed manual contact with a lamp in the operator assembly.Maintained normally-open pushbuttonA maintained NO pushbutton stays in its actuated condition until the documented return operation.Maintained normally-closed pushbuttonA maintained NC pushbutton retains its actuated open state until the documented return action.Key-operated normally-open switchA key-operated NO switch closes a contact through an authorised key mechanism.Key-operated normally-closed switchA key-operated NC switch opens its reference closed contact through the key mechanism.Latched key-operated switchA latched key-operated switch retains its commanded position according to the selected mechanism.Pull-cord switchA pull-cord switch converts a cord-operated mechanical action into an electrical contact change.Foot-operated switchA foot-operated switch uses a pedal mechanism to change an electrical contact.Lever-operated switchA lever-operated switch changes contact state through a manually operated lever.Three-position maintained selectorA three-position maintained selector stays at the selected position until manually moved.Three-position selector returning from leftThis three-position selector has a documented spring return from its left position.Three-position selector returning from rightThis three-position selector returns from its right position according to its mechanism.Three-position centre-return selectorA centre-return selector returns from both outer positions to its documented central rest position.Three-position key selectorA three-position key selector combines position selection with a key-operated mechanism.Four-position maintained selectorA four-position maintained selector provides four stable operating choices.Four-position key selectorA four-position key selector provides key-controlled selection among four documented positions.Normally-open limit switchA normally-open limit switch closes when the documented mechanical travel or position condition actuates it.Normally-closed limit switchA normally-closed limit switch opens when the documented mechanical position actuates it.Roller-operated limit switchA roller-operated limit switch transfers equipment motion through a roller actuator to its electrical contacts.Cam-operated limit switchA cam-operated limit switch changes its electrical contact state when a defined cam profile reaches the actuator.Pressure switch NOA pressure-operated NO switch closes when its documented pressure condition actuates the mechanism.Pressure switch NCA pressure-operated NC switch opens under its documented actuation condition.Temperature switch NOA temperature-operated NO switch changes from open to closed under its specified actuation condition.Temperature switch NCA temperature-operated NC switch opens under a documented thermal condition.Self-operating thermal switchA self-operating thermal switch responds directly to its thermal condition rather than through a separate powered relay input.Float level switch NOA float-operated NO level switch changes contact state through a float mechanism at a documented fluid level.Float level switch NCA float-operated NC level switch opens when its documented level condition actuates the mechanism.Liquid flow switchA liquid-flow switch issues a contact state when a documented flow condition actuates it.Gas flow switchA gas-flow switch changes contact state for a specified gas-flow condition.Inductive proximity switchAn inductive proximity switch detects a documented target without a mechanical contact actuator.Three-wire inductive proximity switchA three-wire inductive proximity switch uses separate supply, common and output conductors.Capacitive proximity switchA capacitive proximity switch detects a target through a change in its sensing capacitance.Magnetic proximity switchA magnetic proximity switch detects a documented magnetic target or field condition.Photoelectric emitter-receiver switchA photoelectric emitter-receiver device uses an optical path to determine a switching output.ThermocoupleA thermocouple produces a temperature-dependent voltage associated with its dissimilar-metal junction system.Resistance temperature detectorAn RTD is a temperature sensor whose resistance changes with temperature.VoltmeterA voltmeter indicates electrical potential difference between its measurement inputs.AmmeterAn ammeter indicates current from a direct or instrument-transformed measurement circuit.Power-factor meterA power-factor meter indicates the relationship between real and apparent power according to the instrument's measurement method.Phase-angle meterA phase-angle meter indicates the phase relationship between documented signals.Frequency meterA frequency meter indicates the frequency of its measured input.Temperature indicatorA temperature indicator displays the temperature derived from its specified sensor or input.TachometerA tachometer indicates rotational speed from its documented sensor or electrical input.Running-hours meterA running-hours meter accumulates elapsed time while its specified enabling condition is active.Ampere-hour meterAn ampere-hour meter integrates current over time for a documented measurement purpose.Recording wattmeterA recording wattmeter measures active power and records it according to the specified instrument.Reactive-power meterA reactive-power meter indicates reactive power using the instrument's documented voltage and current inputs.SynchronoscopeA synchronoscope indicates the phase relationship and relative frequency behaviour of two AC sources.Active-power indicatorAn active-power indicator displays real power derived from its specified measurement inputs.Differential voltmeterA differential voltmeter indicates a difference between documented voltage inputs.Plug and socket connector pairA plug/socket pair represents a detachable electrical connection with two mating sides.Connector plug halfA plug-half representation identifies one side of a detachable connector.Connector socket halfA socket-half representation identifies the mating interface for a detachable plug.Wire spliceA wire splice intentionally joins documented conductors without a detachable connector interface.Earth connectionAn earth connection identifies a documented circuit connection to earth.Functional earthFunctional earth serves an operational purpose such as a documented EMC or signal-reference connection.Protective equipotential bondingProtective equipotential bonding connects documented conductive parts as part of the protective arrangement.Functional equipotential bondingFunctional equipotential bonding connects documented points for an operational or signal-related purpose.Surge arresterA surge arrester diverts a documented surge-related current through its protective path.Gas-discharge protection tubeA gas-discharge tube provides a documented surge-protection path through gas breakdown.Spark-gap protective elementA spark-gap element provides a documented breakdown path across separated electrodes.Variable resistorA variable resistor provides a documented adjustable resistance in a circuit path.PotentiometerA potentiometer uses a movable contact on a resistive element to provide a documented adjustable divider or resistance.Light-dependent resistorA light-dependent resistor changes resistance according to illumination.Heating elementA heating element converts electrical energy to heat in a documented circuit.RC networkAn RC network combines resistance and capacitance in a specified circuit arrangement.VaristorA varistor is a voltage-dependent resistive component used in a documented circuit, often for transient limiting.Current-measuring shuntA current-measuring shunt produces a documented voltage drop corresponding to current through a resistive element.Electrolytic capacitorAn electrolytic capacitor has a specified capacitance, voltage rating and any documented polarity requirement.Feedthrough capacitorA feedthrough capacitor is arranged with a conductor path and a documented capacitive connection used in filtering.Adjustable capacitorAn adjustable capacitor provides a documented variable capacitance.Three-phase power-factor capacitorA three-phase capacitor assembly provides a documented reactive-power function connected to the power circuit.ReactorA reactor is an inductive component used for a documented power-circuit purpose.Iron-core reactorAn iron-core reactor uses a documented magnetic core to provide its inductive characteristic.Gapped-core inductorA gapped-core inductor includes a documented air gap in its magnetic circuit.Adjustable-core inductorAn adjustable-core inductor varies its documented inductive characteristic through a magnetic adjustment.DiodeA diode provides a semiconductor path with documented directional conduction characteristics.PhotodiodeA photodiode is a light-sensitive semiconductor device used in a documented sensing circuit.Zener diodeA Zener diode is a semiconductor component intended for a documented reverse-breakdown operating function.DIACA DIAC is a bidirectional triggering semiconductor device used in a documented control circuit.Single-phase bridge rectifierA single-phase bridge rectifier converts its specified AC input to a DC output through a bridge arrangement.Three-phase bridge rectifierA three-phase bridge rectifier converts a documented three-phase AC input into a DC output.Silicon-controlled rectifierAn SCR is a thyristor with a gate-controlled triggering function in its documented circuit.Gate-turn-off thyristorA gate-turn-off thyristor has a documented gate-controlled turn-off capability.TRIACA TRIAC is a bidirectional thyristor used for a documented AC switching or control function.Bidirectional breakdown diodeA bidirectional breakdown diode provides a documented voltage-limiting semiconductor path in both polarities.Single-phase AC motorA single-phase AC motor represents a load supplied from a documented single-phase source.Single-phase motor with fanA single-phase motor with an associated fan identifies the driven function as well as the electrical load.Three-phase AC motorA three-phase AC motor is a load supplied from three documented phases.Three-phase motor with fanA three-phase motor with fan identifies an electrically driven ventilation or cooling load.Wound-rotor induction motorA wound-rotor induction motor includes a rotor winding arrangement with documented external connections.Three-phase synchronous motorA synchronous motor operates with a documented synchronous relationship to the electrical supply.DC motorA DC motor represents a documented DC electrical load whose armature and any field winding arrangements need to be identified.Permanent-magnet DC motorA permanent-magnet DC motor uses a permanent magnetic field rather than a separately connected field winding.Series-excited DC motorA series-excited DC motor connects its documented field winding in series with the armature circuit.Separately excited DC motorA separately excited DC motor has a documented field circuit supplied separately from the armature circuit.DC generatorA DC generator converts mechanical input into a documented DC electrical output.Compound-excited DC generatorA compound-excited DC generator uses documented series and shunt excitation components.Three-phase synchronous generatorA three-phase synchronous generator supplies a documented AC source associated with its mechanical prime mover and excitation system.Permanent-magnet synchronous generatorA permanent-magnet synchronous generator provides an AC source using a permanent magnetic excitation system.Single-phase AC sourceA single-phase AC source identifies a documented source boundary in a schematic or SLD.Three-phase AC sourceA three-phase AC source identifies a documented three-phase supply boundary.Photovoltaic generatorA photovoltaic generator represents the electrical production of PV cells or modules.Solar generating stationA solar generating station is a system-level representation of a documented solar-generation facility.Wind generating stationA wind generating station is a system-level representation of a documented wind-generation facility.SubstationA substation representation identifies a documented facility boundary in a network or system diagram.Converter substationA converter-substation representation identifies a documented facility where an electrical conversion function forms part of the network connection.Generic electrical loadA generic electrical load identifies a documented consuming circuit or aggregate load on an SLD.Transformer-fed indicator lampA transformer-fed indicator lamp includes a documented internal voltage-conversion arrangement.Push-to-test indicator lampA push-to-test indicator lamp allows a documented local test of the lamp circuit.LED indicator lampAn LED indicator assembly provides a documented visual signal using a semiconductor light source.Flashing indicator lampA flashing indicator lamp provides a documented intermittent visual indication.Flashing beaconA flashing beacon gives a documented conspicuous visual signal.Rotating beaconA rotating beacon provides a documented rotating visual signal through its specified mechanism or assembly.
Public references · Original educational illustrations
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