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Leaders in Solar Safety6 <br />Utilisation Categories <br />Utilisation Categories as are covered in the European Standards EN 60947-1 & EN60947-3 and define an equipment’s intended <br />application. The list of both AC and DC categories for low-voltage switchgear and controlgear are stated in EN 60947-1 Annex A <br />along with the relevant product standards. <br />Manufacturers of both switchgear and controlgear should include in their technical product data all the operational ratings for <br />the utilisation categories for which a product is designed and as such this should remove the confusion for users and designers <br />in their selection of the correct product. <br />If we consider PV installations where there are requirements for switchgear being used on the DC side then the system falls <br />typically within two categories below (for which the relevant standard is EN 60947-3) <br />DC-21 Switching of resistive loads, including moderate overloads <br />DC-22 Switching of mixed resistive and inductive loads, including moderate overloads <br />DC-PV1 Switching of single PV string(s) without reverse and overcurrents <br />DC-PV2 Switching of several PV strings with reverse and overcurrents <br />Compliance to the EN60947-3 utilisation categories involves the products completing a number of tests, these include the <br />“Making and Breaking Capacity” (section 7.2.4.1/D7.2.4.1) and “Operational Performance” (section 7.2.4.2/D7.2.4.2). <br />Verification of the operational making and breaking capacities are stated by reference to the rated operational voltage and rated <br />operational current according to Table 3 and Table D7 (see extracts below). <br />Test Conditions for Making & Breaking Capacities <br />Test Conditions for Number of On Load Operating Cycles <br />I=making current Ic=breaking current Ie=rated operational current <br />U=applied voltage Ue=rated operational voltage Ur=operational frequency or d.c recovery voltage <br />Utlilisation <br />categories <br />Rated <br />operational <br />categories <br />Making Breaking Number <br />of <br />operating <br />cyclesI/Ie U/Ue <br />L/R <br />ms Ic/Ie Ur/Ue <br />L/R <br />ms <br />DC-21A - DC-21B All values 1.5 1.05 1 1.5 1.05 1 5 <br />DC-22B All values 4 1.05 2.5 4 1.05 2.5 5 <br />DC-PV1 All values 1.5 1.05 1 1.5 1.05 1 5 <br />DC-PV2 All values 4 1.05 1 4 1.05 1 5 <br />Utilisation <br />categories <br />Number of <br />operating <br />cycles per <br />hour <br />Number of operating cycles <br />A categories B categories <br />Without current With current Total Without current With current Total <br />DC-21A/B & DC-22B 120 8,500 1,500 10,000 1,700 300 2,000 <br />DC-PV1 & DC-PV2 120 9,700 300 10,000 --- <br />Utilisation <br />categories <br />Rated <br />operational <br />categories <br />Making Breaking <br />I/Ie U/Ue <br />L/R <br />ms Ic/Ie Ur/Ue <br />L/R <br />ms <br />DC-21A - DC-21B All Values 1 1 1 1 1 1 <br />DC-22B All Values 1 1 2 1 1 2 <br />DC-PV1 All Values 1 1 1 1 1 1 <br />DC-PV2 All Values 1 1 1 1 1 1 <br />534 S Sycamore St <br />- 10110979707/01/22