{"id":19089,"date":"2026-10-13T14:30:37","date_gmt":"2026-10-13T06:30:37","guid":{"rendered":"https:\/\/www.wehopower.com\/news\/power-supply-altitude-cooling-insulation\/"},"modified":"2026-10-19T12:05:55","modified_gmt":"2026-10-19T04:05:55","slug":"power-supply-altitude-cooling-insulation","status":"publish","type":"news","link":"https:\/\/www.wehopower.com\/tr\/news\/power-supply-altitude-cooling-insulation\/","title":{"rendered":"Power Supply Altitude Derating: Review Cooling and Insulation Separately"},"content":{"rendered":"<p>For equipment installed at altitude, assess cooling and insulation separately. A supply that remains cool enough may still lack the required insulation qualification, while an electrically suitable product can overheat inside a poorly ventilated cabinet. Do not convert a general ambient-temperature rating into an altitude approval.<\/p>\n<figure data-image-role=\"application_a\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/i1.wp.com\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/01-application-a-60.png?quality=85&#038;strip=all\" alt=\"Power Supply Altitude Derating: Review Cooling and Insulation Separately  title=\" width=\"1536\" height=\"1024\" power supply altitude derating: review cooling and insulation separately title =\"\"><figcaption>A telemetry-cabinet layout prepared for environmental review. The unconnected supply is not evidence of completed altitude qualification.<\/figcaption><\/figure>\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\">\u0130\u00e7indekiler<\/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=\"\u0130\u00e7indekiler Tablosunu A\u00e7\/Kapat\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Ge\u00e7i\u015f yapmak<\/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\/tr\/news\/power-supply-altitude-cooling-insulation\/#Why_the_same_cabinet_can_behave_differently_at_a_higher_site\" >Why the same cabinet can behave differently at a higher site<\/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\/tr\/news\/power-supply-altitude-cooling-insulation\/#What_the_MDR-20-12_sheet_does%E2%80%94and_does_not%E2%80%94establish\" >What the MDR-20-12 sheet does\u2014and does not\u2014establish<\/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\/tr\/news\/power-supply-altitude-cooling-insulation\/#Build_the_thermal_review_around_the_enclosure\" >Build the thermal review around the enclosure<\/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\/tr\/news\/power-supply-altitude-cooling-insulation\/#Review_insulation_requirements_independently\" >Review insulation requirements independently<\/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\/tr\/news\/power-supply-altitude-cooling-insulation\/#Plan_verification_before_the_cabinet_design_is_frozen\" >Plan verification before the cabinet design is frozen<\/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\/tr\/news\/power-supply-altitude-cooling-insulation\/#Frequently_asked_questions\" >Frequently asked questions<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.wehopower.com\/tr\/news\/power-supply-altitude-cooling-insulation\/#Does_a_50%C2%B0C_rating_prove_operation_above_2000_m\" >Does a +50\u00b0C rating prove operation above 2000 m?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/www.wehopower.com\/tr\/news\/power-supply-altitude-cooling-insulation\/#Can_adding_a_fan_or_reducing_load_resolve_every_altitude_issue\" >Can adding a fan or reducing load resolve every altitude issue?<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/www.wehopower.com\/tr\/news\/power-supply-altitude-cooling-insulation\/#A_focused_enquiry_saves_redesign_later\" >A focused enquiry saves redesign later<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"Why_the_same_cabinet_can_behave_differently_at_a_higher_site\"><\/span>Why the same cabinet can behave differently at a higher site<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Reduced air density changes the conditions for convective heat removal and lowers the dielectric strength of air. Manufacturer guidance therefore treats high-altitude selection as more than a temperature calculation. The useful response is a model-specific thermal and insulation review, not a universal \u201creduce the watts by this percentage\u201d rule. <a href=\"https:\/\/www.us.lambda.tdk.com\/resources\/blogs\/20121009.html\" target=\"_blank\" rel=\"noopener\">The referenced technical explanation of altitude effects<\/a> describes these two effects; its historical standards examples are not a substitute for the standards applicable to a new project.<\/p>\n<p>The practical starting point is the actual site envelope: operating altitude, minimum and maximum surrounding temperature, whether the enclosure is conditioned, expected contamination, and the load&#8217;s duty cycle. Distinguish normal operation from transport and storage. Equipment shipped over a mountain pass does not necessarily have the same requirement as equipment operating continuously at that elevation.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"What_the_MDR-20-12_sheet_does%E2%80%94and_does_not%E2%80%94establish\"><\/span>What the MDR-20-12 sheet does\u2014and does not\u2014establish<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The original WEHO MDR-20-12 shown here is a slim DIN-rail supply marked 12 V, 1.67 A. Its matching sheet lists a working-temperature range of \u221210 to +50\u00b0C and dimensions of 22.5 \u00d7 90 \u00d7 100 mm, with TS35\/7.5 or TS35\/15 rail installation.<\/p>\n<p>That sheet does not state a permissible operating altitude or provide an altitude-dependent derating curve. It would therefore be incorrect to advertise this specific unit as qualified for operation above 2000 m\u2014or to assume that 2000 m is its documented limit. The number is a useful enquiry trigger in many engineering discussions, not an automatically established product rating.<\/p>\n<p>The product is used here to show the information an equipment builder must obtain. It is not being presented as a selected high-altitude solution. If the intended installation lacks a matching manufacturer declaration, obtain one or choose a model whose published operating envelope covers the site.<\/p>\n<figure data-image-role=\"product_detail\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/i1.wp.com\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/03-product-detail-57.png?quality=85&#038;strip=all\" alt=\"Power Supply Altitude Derating: Review Cooling and Insulation Separately  title=\" width=\"1536\" height=\"1024\" power supply altitude derating: review cooling and insulation separately title =\"\"><figcaption>The original rear structure determines the rail relationship. Leave ventilation and access decisions tied to the matching installation guidance.<\/figcaption><\/figure>\n<h2><span class=\"ez-toc-section\" id=\"Build_the_thermal_review_around_the_enclosure\"><\/span>Build the thermal review around the enclosure<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Ask for the permitted output at the stated altitude, inlet-air temperature, orientation and cooling arrangement. A temperature measured elsewhere in the room does not describe the air entering a densely packed cabinet. Include heat from controllers, contactors and adjacent converters, along with solar gain or other external heat sources where relevant.<\/p>\n<p>Preserve the original mounting arrangement and ventilation path. For this MDR form, the clip engages the rail at the far rear of the deep blue housing; the front terminal face is not the mounting plane. Extra brackets, improvised orientation and blocked vents can change the installation from the one being assessed.<\/p>\n<p>Adding a fan is a design change, not an automatic approval. Consider the real airflow through the cabinet, filter condition, fan failure, recirculation and maintenance interval. A fan&#8217;s nominal flow number outside the enclosure does not prove the airflow around the supply after ducts, filters and obstructions are present.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Review_insulation_requirements_independently\"><\/span>Review insulation requirements independently<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Give the manufacturer the intended altitude and the applicable finished-equipment requirements. Ask what installation conditions and insulation assumptions apply to the exact model and revision. Do not replace this with an informal visual judgement that two internal parts \u201clook far enough apart.\u201d<\/p>\n<p>A dielectric withstand test value in a component sheet is not an operating-altitude declaration. Likewise, reducing the load current does not by itself resolve an insulation suitability issue. Keep the electrical-safety decision separate from the heat-removal decision in the selection record.<\/p>\n<figure data-image-role=\"engineering_context\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/i1.wp.com\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/04-engineering-context-61.png?quality=85&#038;strip=all\" alt=\"Power Supply Altitude Derating: Review Cooling and Insulation Separately  title=\" width=\"1536\" height=\"1024\" power supply altitude derating: review cooling and insulation separately title =\"\"><figcaption>Passing a thermal review does not establish insulation suitability, and an insulation approval does not establish the usable output in a hot enclosure.<\/figcaption><\/figure>\n<h2><span class=\"ez-toc-section\" id=\"Plan_verification_before_the_cabinet_design_is_frozen\"><\/span>Plan verification before the cabinet design is frozen<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The qualification plan should define the intended environment, representative loads, operating states, measurement locations and acceptance criteria. Have competent engineers select the appropriate test method and evaluate the complete assembly. A conventional room-temperature run can reveal obvious issues, but it cannot silently stand in for an untested altitude condition.<\/p>\n<p>Record the configuration used: supply revision, enclosure, rail position, adjacent equipment, cooling hardware and load profile. If these change after review, assess whether the conclusion still applies. \u201cSame wattage\u201d is not sufficient evidence that a substitute supply has the same thermal or insulation behaviour.<\/p>\n<figure data-image-role=\"application_b\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/i1.wp.com\/www.wehopower.com\/wp-content\/uploads\/2026\/10\/02-application-b-58.png?quality=85&#038;strip=all\" alt=\"Power Supply Altitude Derating: Review Cooling and Insulation Separately  title=\" width=\"1536\" height=\"1024\" power supply altitude derating: review cooling and insulation separately title =\"\"><figcaption>A separate enclosure-layout concept highlights surrounding heat sources and ventilation access. The supply is not shown as an approved high-altitude installation.<\/figcaption><\/figure>\n<h2><span class=\"ez-toc-section\" id=\"Frequently_asked_questions\"><\/span>Frequently asked questions<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<h3><span class=\"ez-toc-section\" id=\"Does_a_50%C2%B0C_rating_prove_operation_above_2000_m\"><\/span>Does a +50\u00b0C rating prove operation above 2000 m?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>No. Ambient temperature and altitude are separate conditions. The matching MDR-20-12 sheet does not provide an altitude approval or an altitude derating curve.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Can_adding_a_fan_or_reducing_load_resolve_every_altitude_issue\"><\/span>Can adding a fan or reducing load resolve every altitude issue?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>No. A suitable thermal change may help heat removal, but it does not by itself establish insulation suitability or a new permissible operating altitude.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"A_focused_enquiry_saves_redesign_later\"><\/span>A focused enquiry saves redesign later<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Send WEHO the exact site altitude, local temperature envelope, required continuous and transient load, enclosure drawings, proposed orientation and applicable equipment requirements. Request the permitted operating envelope and any derating or installation conditions in writing, tied to the exact supplied model.<\/p>\n<p>Use the <a href=\"https:\/\/www.wehopower.com\/tr\/products\/\">WEHO product catalogue<\/a> to identify candidates and <a href=\"https:\/\/www.wehopower.com\/tr\/contact\/\">request an application review<\/a>. The right result may be a documented operating restriction, a different cooling arrangement or a different model. It should not be an invented rating added to an otherwise unchanged product label.<\/p>","protected":false},"excerpt":{"rendered":"<p>A temperature rating is not an altitude approval. Review heat removal and insulation requirements separately before specifying a supply for a high site.<\/p>","protected":false},"author":2,"featured_media":19085,"parent":0,"menu_order":65,"comment_status":"closed","ping_status":"","template":"","format":"standard","meta":{"_acf_changed":false,"_joinchat":[],"footnotes":""},"news_category":[149,284],"class_list":["post-19089","news","type-news","status-publish","format-standard","has-post-thumbnail","hentry","news_category-blog","news_category-product-articles","entry"],"acf":[],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/www.wehopower.com\/tr\/wp-json\/wp\/v2\/news\/19089","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wehopower.com\/tr\/wp-json\/wp\/v2\/news"}],"about":[{"href":"https:\/\/www.wehopower.com\/tr\/wp-json\/wp\/v2\/types\/news"}],"author":[{"embeddable":true,"href":"https:\/\/www.wehopower.com\/tr\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wehopower.com\/tr\/wp-json\/wp\/v2\/comments?post=19089"}],"version-history":[{"count":1,"href":"https:\/\/www.wehopower.com\/tr\/wp-json\/wp\/v2\/news\/19089\/revisions"}],"predecessor-version":[{"id":19617,"href":"https:\/\/www.wehopower.com\/tr\/wp-json\/wp\/v2\/news\/19089\/revisions\/19617"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.wehopower.com\/tr\/wp-json\/wp\/v2\/media\/19085"}],"wp:attachment":[{"href":"https:\/\/www.wehopower.com\/tr\/wp-json\/wp\/v2\/media?parent=19089"}],"wp:term":[{"taxonomy":"news_category","embeddable":true,"href":"https:\/\/www.wehopower.com\/tr\/wp-json\/wp\/v2\/news_category?post=19089"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}