electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems that use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...

utilization categories are defined by

IEC standards The International Electrotechnical Commission (IEC; ) is an international standards organization that prepares and publishes international standards for all electrical, electronic and related technologies. IEC standards cover a vast range of ...

and indicate the type of

electrical load An electrical load is an electrical component or portion of a Electric Circuit, circuit that consumes (active) electric power, such as electrical appliances and Electric light, lights inside the home. The term may also refer to the power Power con ...

and

duty cycle A duty cycle or power cycle is the fraction of one period in which a signal or system is active. Duty cycle is commonly expressed as a percentage or a ratio. A period is the time it takes for a signal to complete an on-and-off cycle. As a for ...

of the loads to ease selection of

contactors A contactor is an electrically controlled switch used for switching an electrical power circuit. A contactor is typically controlled by a circuit which has a much lower power level than the switched circuit, such as a 24-volt coil electromagne ...

and

relays A relay Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts An automotive-style miniature relay with the dust cover taken off A relay is an electrically operated switc ...

Definition

The utilization categories category for low-voltage switchgear defines the characteristic operating conditions for switchgear such as contactors, circuit-breakers, circuit-breaker-fuse units, contactor relays, etc. These devices are dimensioned for different electrical loads and for different operating conditions. The characteristic of the load to be switched or controlled determines the requirements for the switchgear and its correct selection for the intended application. In particular, the stress on the switching path caused by current and voltage during switching on and off is of enormous importance. For example, the switch-on and switch-off current at resistance load corresponds to the continuous operating current, while, for example, squirrel cage motors consumes multiple of the rated operating current during switch-on and in the acceleration phase.

Utilization categories in IEC standard

Contact load in amperes for heaters (AC1) and motors (AC3) can be found directly on the contactor. The "Utilization category" are mainly categorized in IEC 60947 in the following volume: * Volume 1: General requirements * Volume 2: Circuit-breakers * Volume 3: Circuit-breakers, circuit-breakers, switch-disconnectors and switch-fuse units * Volume 4-1: Contactors and motor starters; electromechanical contactors and motor starters * Volume 4-2: Contactors and motor starters - Semiconductor motor controllers and starters for a.c. voltage * Volume 5-1: Control apparatus and switching elements - Electromechanical control apparatus * Volume 6-1: Multi-function switchgear and controlgear - Mains switches (categories AC-32A/B) * Volume 6-2: Multi-function switchgear and controlgear - Control and protective switchgear (CPS) * Volume 7-1: Auxiliary equipment; Terminal blocks for copper conductors * Volume 7-2: Ancillary equipment; protective conductor terminal blocks for copper conductors In addition, IEC/EN 61095 also defines categories for "household and similar applications".

Table

The following table provides an overview of the various abbreviations. Within a utilization category, the suitable size may be selected for the respective type. This depends on the rated current, the rated voltage and the electrical load to be switched. {, class="wikitable" , - ! Utilization category !! Typical application{{cite web, url=https://literature.rockwellautomation.com/idc/groups/literature/documents/rm/lvsam-rm001_-de-p.pdf , title=Niederspannungs-Schaltgeräte , language=de , access-date=2024-01-18!! Applicable IEC norm , - , AC-1 , , Non- inductive or slightly inductive loads, example:

resistive The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual paral ...

furnaces, heaters , , 60947-4-1 , - , AC-2 , , Slip-ring motors: switching off, , 60947-4-1 , - , AC-3 , , Squirrel-cage motors: starting, switches off motors during running time, , 60947-4-1 , - , AC-4 , , Squirrel-cage motors: starting, plugging, inching, , 60947-4-1 , - , AC-5a , , Switching of discharge lamps, , 60947-4-1 , - , AC-5b , , Switching of

incandescent lamps An incandescent light bulb, also known as an incandescent lamp or incandescent light globe, is an electric light that produces illumination by Joule heating a filament until it glows. The filament is enclosed in a glass bulb that is either ...

, , 60947-4-1 , - , AC-6a , , Switching of

transformer In electrical engineering, a transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple Electrical network, circuits. A varying current in any coil of the transformer produces ...

s, , 60947-4-1 , - , AC-6b , , Switching of

capacitor In electrical engineering, a capacitor is a device that stores electrical energy by accumulating electric charges on two closely spaced surfaces that are insulated from each other. The capacitor was originally known as the condenser, a term st ...

banks, , 60947-4-1 , - , AC-7a , , Slightly inductive loads in household appliances: examples: mixers, blenders, , 60947-4-1
61095 , - , AC-7b , , Motor-loads for household appliances: examples: fans, central vacuum, , 60947-4-1
61095 , - , AC-8a , , Hermetic refrigerant compressor motor control with manual resetting overloads, , 60947-4-1 , - , AC-8b , , Hermetic refrigerant compressor motor control with automatic resetting overloads, , 60947-4-1 , - , AC-12 , , Control of resistive loads and solid state loads with opto-coupler isolation, , 60947-5-2 , - , AC-13 , , Control of solid state loads with transformer isolation, , 60947-5-1 , - , AC-14 , , Control of small

electromagnetic In physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is one of the four fundamental forces of nature. It is the dominant force in the interacti ...

loads, , 60947-5-1 , - , AC-15 , , Control of A.C. electromagnetic loads, , 60947-5-1 , - , AC-20 , , Connecting and disconnecting under no-load conditions, , 60947-3 , - , AC-21 , , Switching of resistive loads, including moderate overloads, , 60947-3 , - , AC-22 , , Switching of mixed resistive and inductive loads, including moderate overloads, , 60947-3 , - , AC-23 , , Switching of

motor An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gene ...

loads or other highly inductive loads, , 60947-3 , - , AC-31A
AC-31B ³) , Non-inductive or weakly inductive loads , 60947-6-1 , - , AC-33A
AC33B³) , Motor loads or mixed loads including motors, resistors and up to 30% incandescent lamp load , 60947-6-1 , - , AC-35A
AC-35B ³) , Gas discharge lamp load , 60947-6-1 , - , AC-36A
AC36B ³) , Incandescent lamp load , 60947-6-1 , - , AC-40 , Distribution circuits of mixed resistive and inductive loads , 60947-6-2 , - , AC-41 , Non-inductive or weakly inductive loads, resistance furnaces , 60947-6-2 , - , AC-42 , Slip ring motors: Starting, switching off , 60947-6-2 , - , AC-43 , Squirrel cage motors: Starting, switching off during operation , 60947-6-2 , - , AC-44 , Squirrel cage motors: Starting, counter-current braking ¹) or reversing ¹), typing ²) , 60947-6-2 , - , AC-45a , Switching of gas discharge lamps , 60947-6-2 , - , AC-45b , Switching incandescent lamps , 60947-6-2 , - , AC-51 , Induction-free or slightly inductive loads, resistance furnaces , 60947-4-3 , - , AC-52a , Control of the stator winding of a slip-ring motor: 8-hour operation with starting currents for starting processes, maneuvering, operation , 60947-4-2 , - , AC-52b , Control of the stator winding of a slip ring motor: Intermittent operation , 60947-4-2 , - , AC-53a , Control of a squirrel cage motor: 8-hour operation with starting currents for starting processes, maneuvering, operation , 60947-4-2 , - , AC-53b , Control of a squirrel cage motor: Intermittent operation , 60947-4-2 , - , AC-55a , Switching of electrical controls of discharge lamps , 60947-4-3 , - , AC-55b , Switching incandescent lamps , 60947-4-3 , - , AC-56a , Switching transformers , 60947-4-3 , - , AC-56b , Switching of capacitor batteries , 60947-4-3 , - , AC-58a , Control of a hermetically sealed refrigeration compressor motor with automatic reset of overload releases: 8-hour operation with starting currents for starting, maneuvering, operation , 60947-4-2 , - , AC-58b , The control of a hermetically sealed refrigeration compressor motor with automatic reset of the overload trips: Intermittent operation , 60947-4-2 , - , AC-140 , Control of small electromagnetic loads with holding current ≤ 0.2 A; e.g. contactor relays , 60947-5-2 , - , A , , Protection of circuits, with no rated short-time withstand current, , 60947-3 , - , B , , Protection of circuits, with a rated short-time withstand current, , 60947-3 , - , DC-1 , , Non Inductive or slightly inductive loads, resistance furnaces, heaters, , 60947-4-1 , - , DC-3 , , Shunt-motors, starting, plugging(1), inching(2), dynamic braking of motors, , 60947-4-1 , - , DC-5 , , Series-motors, starting, plugging(1), inching(2), dynamic braking of motors, , 60947-4-1 , - , DC-6 , , Switching of incandescent lamps, , 60947-4-1 , - , DC-12 , , Control of resistive loads and solid state loads with opto-coupler isolation, , 60947-5-1
60947-5-2 , - , DC-13 , , Control of

D.C. Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and federal district of the United States. The city is on the Potomac River, across from Virginia, and shares land borders with ...

electromagnetics, , 60947-5-1
60947-5-2 , - , DC-14 , , Control of D.C. electromagnetic loads having economy resistors in the circuit, , 60947-5-1 , - , DC-20 , , Connecting and disconnecting under no-load conditions, , 60947-5-1 , - , DC-21 , , Switching of resistive loads, including moderate overloads, , 60947-5-1 , - , DC-22 , , Switching of mixed resistive and inductive loads, including moderate overloads (i.e. shunt motors), , 60947-5-1 , - , DC-23 , , Switching of highly inductive loads (i.e. series motors), , 60947-5-1

References

IEC standards

Definition

Utilization categories in IEC standard

Table

See also

References