{"id":2197,"date":"2026-09-21T09:10:00","date_gmt":"2026-09-21T01:10:00","guid":{"rendered":"https:\/\/lemaele.com\/blog\/power-inlet-comparative-tracking-index\/"},"modified":"2026-10-26T11:31:41","modified_gmt":"2026-10-26T03:31:41","slug":"power-inlet-comparative-tracking-index","status":"publish","type":"post","link":"https:\/\/lemaele.com\/de\/blog\/power-inlet-comparative-tracking-index\/","title":{"rendered":"Power Inlet CTI: Match Tracking Evidence to the Actual Insulating Material"},"content":{"rendered":"<style>.lema-article{max-width:100%;min-width:0}.lema-article img{max-width:100%;height:auto}.lema-article table{border-collapse:collapse;min-width:580px}.lema-article th,.lema-article td{border:1px solid #ddd;padding:10px;text-align:left;vertical-align:top}<\/style>\n<div class=\"lema-article\">\n<p>Power inlet comparative tracking index, or CTI, is evidence about the surface-tracking behavior of an insulating material under a specified test. It is not the inlet&#8217;s working-voltage rating, a flame class or a universal creepage distance. Match the material record to the exact molded part, then use the applicable equipment requirements for the insulation assessment. For the <a href=\"https:\/\/lemaele.com\/product\/ipz-series-ac-power-socket\/\">LEMA IPZ family<\/a>, this means requesting a documented connection between the ordered component and its actual insulating material. This guide supplies no CTI value, material group or approved spacing for an unidentified IPZ version.<\/p>\n<h2>Understand the question CTI is intended to answer<\/h2>\n<p>Insulating surfaces can be exposed to electrical stress and contamination under defined conditions. CTI provides a comparative material property determined by its test method. The result belongs to the evaluated material and its documented conditions. It should not be treated as a complete prediction of every surface or every installation in which that material might later appear.<\/p>\n<p>The <a href=\"https:\/\/www.ul.com\/services\/plastic-materials-testing\" rel=\"noopener\" target=\"_blank\">UL plastics testing overview<\/a> identifies electrical tracking among material-evaluation questions and references related procedures. The <a href=\"https:\/\/webstore.iec.ch\/en\/publication\/107319\" rel=\"noopener\" target=\"_blank\">IEC insulation coordination publication<\/a> covers clearances, creepage and solid-insulation criteria within its scope. Together these sources explain why material evidence and equipment insulation assessment are connected but remain separate tasks.<\/p>\n<p>Start an inquiry by asking what conclusion the equipment team needs. If the issue is an unknown resin grade, measuring an external dimension will not answer it. If the issue is a finished-assembly path, a material index alone will not close it. Naming the missing input prevents a document collection exercise from being mistaken for an engineering acceptance decision.<\/p>\n<figure><img decoding=\"async\" src=\"https:\/\/lemaele.com\/wp-content\/uploads\/2026\/10\/lema-power-inlet-comparative-tracking-index-body1-20261026.webp\" alt=\"IPZ-4 male inlet on a dark desk beside separate tools\" width=\"1536\" height=\"1024\" loading=\"lazy\" title=\"\"><figcaption>IPZ-4 male inlet on a dark desk beside separate tools. Product-reference illustration; not a certification, laboratory result or approved installation.<\/figcaption><\/figure>\n<h2>Keep CTI separate from dielectric strength and flame class<\/h2>\n<p>Dielectric strength concerns a different type of insulation behavior and test. A material&#8217;s through-thickness or other withstand information cannot simply be substituted for its tracking evidence. Likewise, a flame classification addresses burning behavior under its defined conditions. The words \u201chigh insulation\u201d or \u201cflame retardant\u201d do not identify a CTI result.<\/p>\n<p>Review the <a href=\"https:\/\/lemaele.com\/blog\/power-inlet-ul94-flammability\/\">UL 94 inlet guide<\/a> for the separate flame-evidence boundary. Keep the property names intact in the purchasing record. A spreadsheet that places several different tests under one column called \u201cplastic rating\u201d invites mistakes because later users may not know which property the recorded value represents.<\/p>\n<p>An electrical current or voltage marking on the component is also a separate claim. It may be supported by a particular component evaluation and conditions, but it does not reveal the resin&#8217;s tracking index by inspection. Ask for the relevant underlying documentation rather than reverse-engineering a material property from the front-panel designation.<\/p>\n<h2>Identify every relevant insulating part<\/h2>\n<p>A power inlet can contain multiple molded or insulating elements. Do not assume that a visible outer housing represents all of them or that they share one formulation. Identify the part and surface relevant to the assessment. Request a drawing, material assignment or supplier statement that connects the evidence to the appropriate region of the exact ordered configuration.<\/p>\n<p>Record the resin manufacturer and grade where available, along with color or other conditions relevant to the published record. A broad polymer family name is insufficient to identify a specific formulation. Additives and manufacturing choices can matter to properties, so the accepted evidence needs a controlled connection to production rather than a visual resemblance to a catalog sample.<\/p>\n<p>If the supplier permits alternative materials, review how equivalence is established for the intended requirement. \u201cEquivalent plastic\u201d is not a complete technical definition. The equipment team should know which properties must be preserved and which records support each approved alternative. Keep unknown material assignments open until the responsible person resolves them.<\/p>\n<h2>Create a tracking-evidence checklist<\/h2>\n<div class=\"lema-table\" style=\"max-width:100%;overflow-x:auto\">\n<table>\n<thead>\n<tr>\n<th scope=\"col\">Review field<\/th>\n<th scope=\"col\">Evidence required<\/th>\n<th scope=\"col\">Avoid<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Property<\/td>\n<td>Named tracking test and reported form<\/td>\n<td>Confusing a class with volts<\/td>\n<\/tr>\n<tr>\n<td>Material<\/td>\n<td>Exact resin identity and relevant conditions<\/td>\n<td>Inferring grade from black color<\/td>\n<\/tr>\n<tr>\n<td>Part mapping<\/td>\n<td>Connection to the relevant molded region<\/td>\n<td>Assuming one material for all parts<\/td>\n<\/tr>\n<tr>\n<td>Equipment use<\/td>\n<td>Applicable insulation requirements and inputs<\/td>\n<td>Selecting spacing from CTI alone<\/td>\n<\/tr>\n<tr>\n<td>Maintenance<\/td>\n<td>Controlled alternatives and changes<\/td>\n<td>Unreviewed equivalent-material substitutions<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>This table contains qualitative questions, not CTI thresholds. The applicable requirements determine how a verified property is used. Do not select a favorable material group first and then search for a document that appears to support it. Begin with the exact material evidence and retain the method, terminology and conditions shown in the original record.<\/p>\n<p>Store the original record together with the supplier-to-component connection. A copied number loses much of its value if its source, revision or material scope cannot be reconstructed. Where documents use a performance class rather than a directly stated value, resolve the meaning through the applicable method instead of treating the class number as volts.<\/p>\n<h2>Connect material evidence to the creepage assessment<\/h2>\n<p>Creepage follows the relevant insulating surface, while clearance concerns a path through air. CTI is part of the material-related evidence used where required by the applicable assessment; it does not erase that distinction. The <a href=\"https:\/\/lemaele.com\/blog\/iec-power-inlet-creepage-clearance-review\/\">creepage and clearance guide<\/a> provides background on identifying assembly paths and their boundaries.<\/p>\n<p>The environment around the surface also matters. The <a href=\"https:\/\/lemaele.com\/blog\/micro-switch-humidity-condensation\/\">humidity and condensation guide<\/a> explains why moisture exposure needs its own review. A high tracking property does not prove that the machine will remain clean or dry. Conversely, a favorable assumed environment does not establish an undocumented material property. Both inputs need support where the equipment assessment uses them.<\/p>\n<p>Use the correct standard and edition for the equipment, with the responsible reviewer&#8217;s interpretation. This article provides no standalone table for choosing millimeters from a CTI number. Such a table would omit other required inputs and could misrepresent the component and installation scope. Preserve the full reasoning behind the accepted spacing rather than only its final dimension.<\/p>\n<figure><img decoding=\"async\" src=\"https:\/\/lemaele.com\/wp-content\/uploads\/2026\/10\/lema-power-inlet-comparative-tracking-index-body2-20261026.webp\" alt=\"IPZ-4 inlet beside a closed blue materials folder\" width=\"1536\" height=\"1024\" loading=\"lazy\" title=\"\"><figcaption>IPZ-4 inlet beside a closed blue materials folder. Product-reference illustration; not a certification, laboratory result or approved installation.<\/figcaption><\/figure>\n<h2>Review the finished assembly rather than only the resin<\/h2>\n<p>Wiring, mounting hardware and nearby conductive parts can change the relevant paths in the assembled equipment. The material property remains useful, but it does not describe every geometric or environmental condition created during installation. Review the released drawing and representative build together, especially where terminal sleeves, brackets or cable routes are part of the accepted arrangement.<\/p>\n<p>Consider manufacturing residues and service conditions within the applicable assessment. A clean molded sample and an assembled inlet region may not present identical surfaces. Identify the process controls relied on by the design and make them reproducible. Do not infer that an unchanged resin grade makes every assembly variation irrelevant.<\/p>\n<p>If a proposed correction uses a coating, sealant or added insulating piece, review the changed system. New materials and processes bring new evidence questions. An informal workshop modification should not be described as a CTI improvement or an accepted spacing solution merely because it covers an exposed surface.<\/p>\n<h2>Handle missing or inconsistent records honestly<\/h2>\n<p>A missing CTI entry means that the particular record does not supply the requested information. It is not automatically a zero result, an unlimited property or proof of failure. Ask the supplier what additional evidence exists and have the equipment reviewer decide how the missing input affects the assessment. Preserve the distinction between missing evidence and a measured unfavorable result.<\/p>\n<p>When two documents disagree, compare identity, revision, method and conditions before choosing one. They may concern different formulations or scopes rather than a simple error. Obtain clarification from the responsible supplier or evaluator and retain the resolution. Picking the larger-looking value without understanding its source creates an unreliable acceptance record.<\/p>\n<p>The same caution applies to a generic material sample offered for testing. Confirm whether it represents the actual production formulation and relevant conditions. A laboratory report is only as useful as its connection to the ordered component. Keep that identity chain visible from the material source through the inlet to the equipment build.<\/p>\n<h2>Make procurement and changes traceable<\/h2>\n<p>The inquiry should identify the inlet order code, relevant insulating part, equipment requirement and documentation requested. Explain that the goal is to support the actual insulation assessment rather than collect a generic certificate. This makes it easier for the supplier to provide the right record or clearly state what is unavailable.<\/p>\n<p>Keep the accepted material assignment and change triggers in the controlled file. A different resin, color, molding source or relevant construction change may require review. Connect these records to the <a href=\"https:\/\/lemaele.com\/blog\/switch-supplier-change-notification\/\">supplier change process<\/a> so a later substitution does not silently break the evidence chain.<\/p>\n<p>The final result should state what material property is supported and how it was used, with the remaining assumptions recorded. Do not label the entire inlet \u201cCTI approved\u201d without explaining the scope. Clear evidence boundaries help both the buyer and the equipment designer make a defensible decision.<\/p>\n<h2>Insulation standard background video<\/h2>\n<p>Elektor TV: PCB Clearance and Creepage Distances, Part 1: Which Standard Applies?<\/p>\n<div style=\"position:relative;width:100%;aspect-ratio:16\/9\"><iframe style=\"position:absolute;inset:0;width:100%;height:100%;border:0\" src=\"https:\/\/www.youtube-nocookie.com\/embed\/0Vhb60wnW3U\" title=\"PCB Clearance and Creepage Distances, Part 1: Which Standard Applies?\" loading=\"lazy\" allow=\"accelerometer; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe><\/div>\n<p><a rel=\"noopener\" href=\"https:\/\/www.youtube.com\/watch?v=0Vhb60wnW3U\" target=\"_blank\">Watch PCB Clearance and Creepage Distances, Part 1: Which Standard Applies?<\/a>.<\/p>\n<p>Elektor TV discusses selecting the standard behind clearance and creepage requirements. It supports the connection between material inputs and the equipment assessment. It does not measure CTI, assign a value to an IPZ material or replace the exact supplier and laboratory documentation required for the review.<\/p>\n<h2>Frequently asked questions<\/h2>\n<h3>Is CTI the inlet working voltage?<\/h3>\n<p>No. CTI concerns a material tracking test. It is not a component operating-voltage rating or a universal permitted voltage for the assembled equipment.<\/p>\n<h3>Can I choose creepage from CTI alone?<\/h3>\n<p>No. The applicable equipment assessment uses other relevant inputs, including the insulation purpose and environmental conditions. Use the correct requirements and complete evidence.<\/p>\n<h3>Does a missing CTI entry mean the material failed?<\/h3>\n<p>Not necessarily. It means the reviewed record does not supply that information. Preserve the missing evidence and obtain clarification rather than assigning an invented result.<\/p>\n<h3>Does this article assign IPZ material to a tracking group?<\/h3>\n<p>No. The exact material record and supplier connection to the ordered part must be established before using a material group in the equipment review.<\/p>\n<\/div>\n<p><script type=\"application\/ld+json\">{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"Is CTI the inlet working voltage?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"No. CTI concerns a material tracking test. It is not a component operating-voltage rating or a universal permitted voltage for the assembled equipment.\"}}, {\"@type\": \"Question\", \"name\": \"Can I choose creepage from CTI alone?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"No. The applicable equipment assessment uses other relevant inputs, including the insulation purpose and environmental conditions. Use the correct requirements and complete evidence.\"}}, {\"@type\": \"Question\", \"name\": \"Does a missing CTI entry mean the material failed?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Not necessarily. It means the reviewed record does not supply that information. 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