{"id":20379,"date":"2026-10-30T10:12:01","date_gmt":"2026-10-30T02:12:01","guid":{"rendered":"https:\/\/www.wehopower.com\/news\/edr75-overvoltage-category-location\/"},"modified":"2026-10-30T10:12:01","modified_gmt":"2026-10-30T02:12:01","slug":"edr75-overvoltage-category-location","status":"publish","type":"news","link":"https:\/\/www.wehopower.com\/th\/news\/edr75-overvoltage-category-location\/","title":{"rendered":"Overvoltage Category at the Supply Location: What the Panel Design Must Establish"},"content":{"rendered":"<div class=\"weho-blog-content\">\n<p><strong>Establish the overvoltage-category requirement at the supply\u2019s installation location, then obtain evidence that the exact power-supply version meets the applicable insulation-coordination requirements.<\/strong> Neither a DIN-rail housing nor a nominal input-voltage range settles that decision.<\/p>\n<p>This article helps a panel designer assemble the location and product evidence needed for an assessment. The WEHO EDR-75-24 is the product example; no overvoltage-category qualification is asserted for it from the available public documents.<\/p>\n<nav class=\"toc\" aria-label=\"Article contents\">\n<p>In this article<\/p>\n<ol>\n<li><a href=\"#meaning\">Separate an input rating from a transient requirement<\/a><\/li>\n<li><a href=\"#location\">Write a location statement that a supplier can assess<\/a><\/li>\n<li><a href=\"#model-evidence\">Request evidence for EDR-75-24 without filling gaps by inference<\/a><\/li>\n<li><a href=\"#example\">A panel quotation can be complete electrically and incomplete for location<\/a><\/li>\n<li><a href=\"#release\">Close the requirement-to-evidence loop<\/a><\/li>\n<\/ol>\n<\/nav>\n<section id=\"meaning\">\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_86 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">\u0e2a\u0e32\u0e23\u0e1a\u0e31\u0e0d<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">\u0e2a\u0e25\u0e31\u0e1a<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewbox=\"0 0 24 24\" version=\"1.2\" baseprofile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.wehopower.com\/th\/news\/edr75-overvoltage-category-location\/#Separate_an_input_rating_from_a_transient_requirement\" >Separate an input rating from a transient requirement<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.wehopower.com\/th\/news\/edr75-overvoltage-category-location\/#Write_a_location_statement_that_a_supplier_can_assess\" >Write a location statement that a supplier can assess<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.wehopower.com\/th\/news\/edr75-overvoltage-category-location\/#Request_evidence_for_EDR-75-24_without_filling_gaps_by_inference\" >Request evidence for EDR-75-24 without filling gaps by inference<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.wehopower.com\/th\/news\/edr75-overvoltage-category-location\/#A_panel_quotation_can_be_complete_electrically_and_incomplete_for_location\" >A panel quotation can be complete electrically and incomplete for location<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.wehopower.com\/th\/news\/edr75-overvoltage-category-location\/#Close_the_requirement-to-evidence_loop\" >Close the requirement-to-evidence loop<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.wehopower.com\/th\/news\/edr75-overvoltage-category-location\/#Use_the_project_record\" >Use the project record<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.wehopower.com\/th\/news\/edr75-overvoltage-category-location\/#Request_the_EDR-75-24_evidence_needed_for_your_installation\" >Request the EDR-75-24 evidence needed for your installation<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/www.wehopower.com\/th\/news\/edr75-overvoltage-category-location\/#Sources_and_further_reading\" >Sources and further reading<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"Separate_an_input_rating_from_a_transient_requirement\"><\/span>Separate an input rating from a transient requirement<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>A normal input-voltage range describes a supply\u2019s permitted operating input under stated conditions. Overvoltage category concerns the transient environment considered in insulation coordination. A surge-immunity test entry, an output overvoltage-protection function and a dielectric test value answer other questions; they are not interchangeable evidence.<\/p>\n<p><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/59671\" target=\"_blank\" rel=\"noopener\">IEC 60664-1<\/a> addresses insulation coordination for low-voltage supply systems, including clearances, creepage distances, solid insulation and related tests. Its public listing also identifies a consolidated version incorporating Amendment 1:2025. The assessor should identify the edition and any product-specific requirements applicable to the project.<\/p>\n<p><a href=\"https:\/\/www.us.lambda.tdk.com\/resources\/blogs\/20171107.html\" target=\"_blank\" rel=\"noopener\">TDK-Lambda\u2019s overvoltage-category overview<\/a> relates the categories to locations within an installation. Use such guidance to frame the question, then apply the actual project standard. \u201cIndustrial power supply\u201d is a product description, not a documented category assignment.<\/p>\n<figure class=\"figure\" id=\"figure-diagram\"><picture><source media=\"(max-width: 600px)\" srcset=\"https:\/\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/decision-map-mobile-8.svg\" width=\"480\" height=\"1390\" type=\"image\/svg+xml\"><img loading=\"lazy\" src=\"https:\/\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/decision-map-8.svg\" alt=\"Overvoltage Category at the Supply Location: What the Panel Design Must Establish  title=\" width=\"1200\" height=\"740\" decoding=\"async\" overvoltage category at the supply location: what panel design must establish title =\"\"><\/picture><figcaption>Match the location requirement to model evidence. A four-part qualification record links installation location, assessed transient requirement, exact-model evidence and a documented release decision. <a class=\"original-link\" href=\"https:\/\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/decision-map-8.svg\">View original image<\/a><\/figcaption><\/figure>\n<\/section>\n<section id=\"location\">\n<h2><span class=\"ez-toc-section\" id=\"Write_a_location_statement_that_a_supplier_can_assess\"><\/span>Write a location statement that a supplier can assess<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Identify the proposed point of connection using the electrical drawing. State the supply system, the relevant voltage, how the equipment connects to the installation and the environmental conditions required by the assessment. If upstream protective measures form part of the proposal, identify their exact documentation and configuration.<\/p>\n<p>Do not shorten this to \u201cinside a control cabinet.\u201d That phrase does not tell a reviewer where the cabinet is supplied from or what transient assumptions the design relies on. Similarly, placing a device farther from a distribution board does not, by itself, prove a particular transient boundary.<\/p>\n<div class=\"table-wrap\">\n<table>\n<thead>\n<tr>\n<th scope=\"col\">Assessment input<\/th>\n<th scope=\"col\">What to put in the project record<\/th>\n<th scope=\"col\">Reason it affects the decision<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<th scope=\"row\">Connection location<\/th>\n<td>Drawing reference, supply origin and equipment connection arrangement.<\/td>\n<td>Makes the installation assumption traceable.<\/td>\n<\/tr>\n<tr>\n<th scope=\"row\">Electrical system<\/th>\n<td>Applicable nominal voltage, earthing-system description and assessment standard.<\/td>\n<td>Prevents comparison of ratings based on different conditions.<\/td>\n<\/tr>\n<tr>\n<th scope=\"row\">Required category \/ impulse basis<\/th>\n<td>Requirement, responsible assessor and supporting standard clause or assessment report.<\/td>\n<td>States what the selected product has to satisfy.<\/td>\n<\/tr>\n<tr>\n<th scope=\"row\">Installation environment<\/th>\n<td>Pollution, altitude and other conditions required by the applicable assessment.<\/td>\n<td>Category alone does not define every insulation condition.<\/td>\n<\/tr>\n<tr>\n<th scope=\"row\">Proposed protection<\/th>\n<td>Exact devices and installation conditions if relied upon.<\/td>\n<td>Allows the complete arrangement, rather than a component name, to be reviewed.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>The record is an information request for the responsible designer or conformity assessor. It is not a method for assigning a category by visual inspection.<\/p>\n<\/section>\n<section id=\"model-evidence\">\n<h2><span class=\"ez-toc-section\" id=\"Request_evidence_for_EDR-75-24_without_filling_gaps_by_inference\"><\/span>Request evidence for EDR-75-24 without filling gaps by inference<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u0e17\u0e35\u0e48 <a href=\"https:\/\/www.wehopower.com\/th\/product\/edr-dinrail-75w-ac-to-dc-single-output-switching-power-supply\/\">WEHO EDR-75 product page<\/a> \u0e41\u0e25\u0e30 <a href=\"https:\/\/www.wehopower.com\/wp-content\/uploads\/2021\/11\/EDR-75.pdf\">EDR-75 specification sheet<\/a> identify the DIN-rail family and a 24 V model. The available sheet does not provide an explicit overvoltage-category declaration. General product-page certification text is not sufficient evidence for that missing field.<\/p>\n<p>Ask for the current document applicable to the exact suffix and construction revision: the category or rated impulse-withstand claim, its standard and conditions, any restrictions, and the test or approval reference supporting it. If the supplier provides a certificate, check that the covered model and relevant scope match the offered unit.<\/p>\n<p><a href=\"https:\/\/www.hummel.com\/en\/circular-connectors\/technical-center-circular-connectors\/general-technical-information\/\" target=\"_blank\" rel=\"noopener\">HUMMEL\u2019s technical definitions<\/a> distinguish rated voltage from rated impulse voltage, which describes specified insulation withstand against transient overvoltages. That distinction is useful when comparing document fields, but HUMMEL component data does not establish an EDR-75 rating.<\/p>\n<p>A missing category field is an unresolved qualification question. It is not evidence that the product passes or fails the proposed location requirement. Keep the model as a candidate only within the project\u2019s document-review status.<\/p>\n<\/section>\n<section id=\"example\">\n<h2><span class=\"ez-toc-section\" id=\"A_panel_quotation_can_be_complete_electrically_and_incomplete_for_location\"><\/span>A panel quotation can be complete electrically and incomplete for location<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>In a hypothetical procurement review, a cabinet designer selects a 24 V DIN-rail supply that fits the available space and the continuous load. The customer specification also calls for installation suitability under a stated transient environment. The quotation includes an output table and a generic compliance statement, but no exact-model evidence for that requirement.<\/p>\n<p>The appropriate disposition is \u201crequest installation qualification evidence.\u201d The output table can support the load-selection discussion while the location requirement remains open. Approving the full assembly because the supply has enough watts would combine two independent decisions.<\/p>\n<p>If someone proposes an upstream surge-protective device, refer the complete arrangement to the responsible assessor. Its presence alone does not prove the insulation qualification of the supply, establish a category reduction or eliminate the need to assess coordination and installation conditions.<\/p>\n<\/section>\n<section id=\"release\">\n<h2><span class=\"ez-toc-section\" id=\"Close_the_requirement-to-evidence_loop\"><\/span>Close the requirement-to-evidence loop<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The release record should place the required installation condition beside the offered model\u2019s documented condition. Where they differ, record the approved engineering resolution and its evidence. A verbal assurance that a product is commonly used in cabinets cannot close a model-specific qualification item.<\/p>\n<p>Retain the exact document revisions with the bill of materials. Recheck the decision if the supply construction, installation location, system voltage or relied-upon protection changes. Purchasing should request approval of substitutions against these recorded conditions, rather than treating all DIN-rail supplies with the same output voltage as equivalents.<\/p>\n<p>This approach lets engineering and purchasing make a clear decision: approve a documented match, request the missing evidence, or select a candidate with the necessary supported rating. It avoids inventing an EDR-75-24 category that the public material does not state.<\/p>\n<\/section>\n<section id=\"project-record\">\n<h2><span class=\"ez-toc-section\" id=\"Use_the_project_record\"><\/span>Use the project record<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><a href=\"\/th\/acceptance-record.html\/\">Open the blank Supply Installation Location \u2014 Insulation Evidence Record<\/a> to record your conditions, evidence and decisions. The worksheet contains no pre-approved result.<\/p>\n<\/section>\n<section class=\"cta\" id=\"project-review\">\n<h2><span class=\"ez-toc-section\" id=\"Request_the_EDR-75-24_evidence_needed_for_your_installation\"><\/span>Request the EDR-75-24 evidence needed for your installation<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Send WEHO your exact installation-location requirement, applicable standard and edition, supply-system details and proposed model. Ask for the current model-specific documents so your panel designer can assess the offered construction against that requirement.<\/p>\n<p><a href=\"https:\/\/www.wehopower.com\/th\/contact\/\">Contact WEHO about EDR-75-24 qualification documents<\/a><\/p>\n<\/section>\n<section class=\"sources\" id=\"sources\">\n<h2><span class=\"ez-toc-section\" id=\"Sources_and_further_reading\"><\/span>Sources and further reading<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<ol>\n<li><a href=\"https:\/\/www.wehopower.com\/th\/product\/edr-dinrail-75w-ac-to-dc-single-output-switching-power-supply\/\">WEHO EDR-75 DIN-rail power supply product information<\/a><\/li>\n<li><a href=\"https:\/\/www.wehopower.com\/wp-content\/uploads\/2021\/11\/EDR-75.pdf\">WEHO EDR-75 specification sheet<\/a><\/li>\n<li><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/59671\" target=\"_blank\" rel=\"noopener\">IEC 60664-1 public scope and consolidated-version listing<\/a><\/li>\n<li><a href=\"https:\/\/www.us.lambda.tdk.com\/resources\/blogs\/20171107.html\" target=\"_blank\" rel=\"noopener\">TDK-Lambda \u2014 Power Supply Overvoltage Category (OVC)<\/a><\/li>\n<li><a href=\"https:\/\/www.hummel.com\/en\/circular-connectors\/technical-center-circular-connectors\/general-technical-information\/\" target=\"_blank\" rel=\"noopener\">HUMMEL \u2014 General technical information: rated impulse voltage<\/a><\/li>\n<\/ol>\n<\/section>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>An industrial enclosure or DIN rail does not establish a power supply\u2019s overvoltage category. Match the installation requirement to documented exact-model evidence.<\/p>","protected":false},"author":2,"featured_media":20368,"parent":0,"menu_order":12,"comment_status":"","ping_status":"","template":"","format":"standard","meta":{"_acf_changed":false,"_joinchat":[],"footnotes":""},"news_category":[284],"class_list":["post-20379","news","type-news","status-publish","format-standard","has-post-thumbnail","hentry","news_category-product-articles","entry"],"acf":[],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/www.wehopower.com\/th\/wp-json\/wp\/v2\/news\/20379","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wehopower.com\/th\/wp-json\/wp\/v2\/news"}],"about":[{"href":"https:\/\/www.wehopower.com\/th\/wp-json\/wp\/v2\/types\/news"}],"author":[{"embeddable":true,"href":"https:\/\/www.wehopower.com\/th\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wehopower.com\/th\/wp-json\/wp\/v2\/comments?post=20379"}],"version-history":[{"count":0,"href":"https:\/\/www.wehopower.com\/th\/wp-json\/wp\/v2\/news\/20379\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.wehopower.com\/th\/wp-json\/wp\/v2\/media\/20368"}],"wp:attachment":[{"href":"https:\/\/www.wehopower.com\/th\/wp-json\/wp\/v2\/media?parent=20379"}],"wp:term":[{"taxonomy":"news_category","embeddable":true,"href":"https:\/\/www.wehopower.com\/th\/wp-json\/wp\/v2\/news_category?post=20379"}],"curies":[{"name":"\u0e2b\u0e19\u0e49\u0e32","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}