{"id":1871,"date":"2026-07-10T10:52:43","date_gmt":"2026-07-10T10:52:43","guid":{"rendered":"https:\/\/cnfuerte.com\/blog\/disconnector-switch-selection-guide-for-medium-voltage-overhead-lines\/"},"modified":"2026-07-10T10:52:46","modified_gmt":"2026-07-10T10:52:46","slug":"disconnector-switch-selection-guide-for-medium-voltage-overhead-lines","status":"publish","type":"post","link":"https:\/\/cnfuerte.com\/ru\/blog\/disconnector-switch-selection-guide-for-medium-voltage-overhead-lines\/","title":{"rendered":"Disconnector Switch Selection Guide for Medium-Voltage Overhead Lines"},"content":{"rendered":"<div class=\"b2b-article\" style=\"max-width:820px;margin:0 auto;\">\n<p style=\"margin:0 0 16px;line-height:1.7;\"><strong>Disconnector switch<\/strong>es sectionalize medium-voltage overhead feeders and give crews a visible open point for maintenance\u2014yet catalog pages rarely explain how voltage class, continuous current, and basic insulation level interact on real utility specifications. This guide focuses on practical evaluation steps for utility, EPC, and industrial buyers\u2014ratings, documentation, and lifecycle support\u2014not generic marketing claims. Where equipment selection is involved, cross-check public specifications on cnfuerte.com and confirm project-specific limits with your utility or consulting engineer. Section checklists can be reused as RFQ attachments and commissioning handover outlines.<\/p>\n<nav style=\"background:#f7f9fb;border:1px solid #e3e8ee;border-radius:8px;padding:14px 18px;margin:0 0 24px;\">\n<p style=\"margin:0 0 16px;line-height:1.7;\"><strong>On this page<\/strong><\/p>\n<ul style=\"margin:0 0 18px 1.2em;line-height:1.7;\">\n<li style=\"margin:0 0 16px;line-height:1.7;\"><a href=\"#part-1-what-a-disconnector-switch-does-on-mv-fee\">Part 1. What a Disconnector Switch Does on MV Feeders<\/a><\/li>\n<li style=\"margin:0 0 16px;line-height:1.7;\"><a href=\"#part-2-key-ratings-voltage-current-and-bil\">Part 2. Key Ratings: Voltage, Current, and BIL<\/a><\/li>\n<li style=\"margin:0 0 16px;line-height:1.7;\"><a href=\"#part-3-load-break-vs-disconnect-only-application\">Part 3. Load-Break vs Disconnect-Only Applications<\/a><\/li>\n<li style=\"margin:0 0 16px;line-height:1.7;\"><a href=\"#part-4-documentation-and-handover-checklist\">Part 4. Documentation and Handover Checklist<\/a><\/li>\n<li style=\"margin:0 0 16px;line-height:1.7;\"><a href=\"#part-5-commissioning-monitoring-and-long-term-op\">Part 5. Commissioning, Monitoring, and Long-Term Operations<\/a><\/li>\n<\/ul>\n<\/nav>\n<figure style=\"margin:26px 0;text-align:center;\"><img loading=\"lazy\" decoding=\"async\" style=\"max-width:640px;width:100%;height:auto;display:block;margin:0 auto;border-radius:8px;\" src=\"https:\/\/cnfuerte.com\/wp-content\/uploads\/2026\/07\/disconnector-switch-selection-guide-for-medium-voltage-overhead-lines-cover.webp\" alt=\"Disconnector switch on medium-voltage overhead line \u2014 concept illustration (not a product photo)\" width=\"640\" height=\"360\"\/><\/figure>\n<h2 id=\"part-1-what-a-disconnector-switch-does-on-mv-fee\" style=\"margin:42px 0 14px;font-size:1.35em;line-height:1.3;\">Part 1. What a Disconnector Switch Does on MV Feeders<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7;\">On distribution networks, disconnectors isolate equipment or line sections while providing visible verification that conductors are open.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">They are not substitutes for circuit breakers unless explicitly rated for fault interruption or load-break duty.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Distribution protection projects succeed when utility standards, EPC design, and procurement stay aligned from concept through commissioning.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Document nominal voltage, fault level, and ambient conditions before final equipment selection.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Use conservative language for performance claims until site-specific studies confirm targets.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Capture nominal voltage, available fault current, altitude, and utility clearance requirements in the RFQ package to reduce technical back-and-forth.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Type test evidence from independent laboratories (KEMA, CESI, or equivalent) supports utility acceptance better than marketing datasheets alone.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Define acceptance criteria before shipment\u2014dielectric withstand, mechanical operation, and nameplate ratings\u2014so commissioning disputes are less likely.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Export RFQs should state pollution class, altitude correction, target standard family (IEC 62271 \/ IEEE C37), and spare-parts expectations up front.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Document conductor size, pole hardware, and switching procedure limits so field crews install the same configuration the factory tested.<\/p>\n<div class=\"tip-box\" style=\"border-left:4px solid #2e7d32;background:#f3faf4;padding:12px 16px;margin:0 0 18px;line-height:1.7;\"><strong>Tip:<\/strong> Confirm utility or national standard (IEC\/IEEE) before final device selection.<\/div>\n<h2 id=\"part-2-key-ratings-voltage-current-and-bil\" style=\"margin:42px 0 14px;font-size:1.35em;line-height:1.3;\">Part 2. Key Ratings: Voltage, Current, and BIL<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Specify rated voltage at or above maximum system voltage, continuous current to match conductor ampacity, and BIL aligned with insulation coordination studies.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Momentary and short-time withstand values must exceed expected fault duty at the installation point.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Compare total installed cost including mounting hardware, spares, and commissioning.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Internal links to <a href=\"https:\/\/cnfuerte.com\/fuse-cutout\/\">fuse cutout product line<\/a>, <a href=\"https:\/\/cnfuerte.com\/lightning-arrester\/\">surge arrester product line<\/a>, <a href=\"https:\/\/cnfuerte.com\/polymer-insulator\/\">polymer insulator product line<\/a>, and <a href=\"https:\/\/cnfuerte.com\/vacuum-circuit-breaker\/\">vacuum circuit breaker product line<\/a> help buyers navigate cnfuerte.com.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Lead times and MOQ vary by configuration; confirm for export shipments.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Capture nominal voltage, available fault current, altitude, and utility clearance requirements in the RFQ package to reduce technical back-and-forth.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Type test evidence from independent laboratories (KEMA, CESI, or equivalent) supports utility acceptance better than marketing datasheets alone.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Define acceptance criteria before shipment\u2014dielectric withstand, mechanical operation, and nameplate ratings\u2014so commissioning disputes are less likely.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Export RFQs should state pollution class, altitude correction, target standard family (IEC 62271 \/ IEEE C37), and spare-parts expectations up front.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Document conductor size, pole hardware, and switching procedure limits so field crews install the same configuration the factory tested.<\/p>\n<figure style=\"margin:26px 0;text-align:center;\"><img loading=\"lazy\" decoding=\"async\" style=\"max-width:640px;width:100%;height:auto;display:block;margin:0 auto;border-radius:8px;\" src=\"https:\/\/cnfuerte.com\/wp-content\/uploads\/2026\/07\/disconnector-switch-selection-guide-for-medium-voltage-overhead-lines-body.webp\" alt=\"disconnector switch \u2014 FUERTE official product with illustrative industrial background (not a real site photo)\" width=\"640\" height=\"360\"\/><\/figure>\n<div class=\"warning-box\" style=\"border-left:4px solid #f9a825;background:#fffbf0;padding:12px 16px;margin:0 0 18px;line-height:1.7;\"><strong>Important:<\/strong> Do not energize medium-voltage equipment without verified grounding, approved protection settings, and compliance with minimum approach distances and lockout\/tagout procedures.<\/div>\n<h2 id=\"part-3-load-break-vs-disconnect-only-application\" style=\"margin:42px 0 14px;font-size:1.35em;line-height:1.3;\">Part 3. Load-Break vs Disconnect-Only Applications<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Load-break hooks or self-contained loadbreak mechanisms allow limited switching under load where utility rules permit.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Disconnect-only devices require de-energization before operation\u2014confirm duty with your switching procedures.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Post-commissioning, schedule periodic inspection of fuse links, insulator surfaces, and VCB contact wear.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Keep spare fuse links and critical hardware identified in the maintenance plan.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Submit project parameters via <a href=\"https:\/\/cnfuerte.com\/contact-us\/\">FUERTE contact<\/a> for engineering feedback.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Capture nominal voltage, available fault current, altitude, and utility clearance requirements in the RFQ package to reduce technical back-and-forth.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Type test evidence from independent laboratories (KEMA, CESI, or equivalent) supports utility acceptance better than marketing datasheets alone.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Define acceptance criteria before shipment\u2014dielectric withstand, mechanical operation, and nameplate ratings\u2014so commissioning disputes are less likely.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Export RFQs should state pollution class, altitude correction, target standard family (IEC 62271 \/ IEEE C37), and spare-parts expectations up front.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Document conductor size, pole hardware, and switching procedure limits so field crews install the same configuration the factory tested.<\/p>\n<div class=\"tip-box\" style=\"border-left:4px solid #2e7d32;background:#f3faf4;padding:12px 16px;margin:0 0 18px;line-height:1.7;\"><strong>Tip:<\/strong> Keep as-built single-line diagrams updated after any feeder or protection changes.<\/div>\n<h2 id=\"part-4-documentation-and-handover-checklist\" style=\"margin:42px 0 14px;font-size:1.35em;line-height:1.3;\">Part 4. Documentation and Handover Checklist<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Utility acceptance should not rely on energization alone\u2014documentation proves ratings, safety, and maintainability.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Use the tables below as a starting RFQ checklist; your utility or EPC contract may require additional items.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">For product-specific datasheets, cross-check <a href=\"https:\/\/cnfuerte.com\/isolating-switch\/\">related FUERTE product pages<\/a> and request missing type test excerpts.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Align factory acceptance tests with items your insurer or utility interconnection agreement may require.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">When comparing quotations, normalize currency, Incoterms, and included commissioning services before ranking suppliers.<\/p>\n<table style=\"width:100%;border-collapse:collapse;margin:0 0 20px;\">\n<thead>\n<tr>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f4f7fa;text-align:left;\">Document \/ item<\/th>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f4f7fa;text-align:left;\">Purpose<\/th>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f4f7fa;text-align:left;\">When to request<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Factory type test report<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Verify rated voltage, kA\/kV, and temperature rise<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Before purchase order<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Installation &#038; wiring diagram<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Mounting, clearances, and grounding<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Design phase<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Spare parts list (5+ year)<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Fuse links, gaskets, contact kits<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Contract negotiation<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Commissioning checklist<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Acceptance tests and as-built records<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Before energization<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">OEM\/ODM drawing approval<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Custom labels, brackets, or creepage<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Before production release<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<table style=\"width:100%;border-collapse:collapse;margin:0 0 20px;\">\n<thead>\n<tr>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f4f7fa;text-align:left;\">Use case<\/th>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f4f7fa;text-align:left;\">Operational need<\/th>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f4f7fa;text-align:left;\">Typical approach<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Line sectionalizing<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Visible break for maintenance<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Load-break or disconnect per utility rules<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Transformer isolation<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Lockout\/tagout during service<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Interlocks with VCB or fuses upstream<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Bypass arrangements<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Temporary parallel paths<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Manual operation with clear labeling<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Export projects<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Local utility standards<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px;vertical-align:top;\">Confirm short-time withstand and creepage<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<div class=\"tip-box\" style=\"border-left:4px solid #2e7d32;background:#f3faf4;padding:12px 16px;margin:0 0 18px;line-height:1.7;\"><strong>Tip:<\/strong> Store factory test reports with serial numbers for future warranty claims.<\/div>\n<div class=\"tip-box\" style=\"border-left:4px solid #2e7d32;background:#f3faf4;padding:12px 16px;margin:0 0 18px;line-height:1.7;\"><strong>Tip:<\/strong> Confirm imperial and metric dimensions if shipping to mixed-design sites.<\/div>\n<h2 id=\"part-5-commissioning-monitoring-and-long-term-op\" style=\"margin:42px 0 14px;font-size:1.35em;line-height:1.3;\">Part 5. Commissioning, Monitoring, and Long-Term Operations<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Commissioning should verify nameplate ratings, mechanical operation, and insulation integrity at the installation site\u2014not only at the factory.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Functional tests typically include contact resistance, timing tests for VCBs, fuse link continuity checks, and visual insulator inspection.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Monitoring after energization helps catch loose hardware, tracking on insulators, or abnormal heating before outages occur.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Train maintenance staff on lockout\/tagout, visible open verification for switches, and safe fuse link replacement procedures.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Schedule periodic reviews after major load changes or renewable integration\u2014fault levels and coordination may shift.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Utility account managers can clarify inspection intervals and reporting requirements for grid-connected equipment.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Keep a spare-parts criticality list (fuse links, gaskets, contact kits) based on lead time and production impact.<\/p>\n<div class=\"tip-box\" style=\"border-left:4px solid #2e7d32;background:#f3faf4;padding:12px 16px;margin:0 0 18px;line-height:1.7;\"><strong>Tip:<\/strong> Log baseline insulation and contact resistance measurements after commissioning for future comparisons.<\/div>\n<h2 style=\"margin:42px 0 14px;font-size:1.35em;line-height:1.3;\">Recommended FUERTE Products<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7;\">For project support, explore our <a href=\"https:\/\/cnfuerte.com\/isolating-switch\/\">related product line<\/a>, <a href=\"https:\/\/cnfuerte.com\/products\/\">product catalog<\/a>, and <a href=\"https:\/\/cnfuerte.com\/oem-odm\/\">OEM\/ODM capabilities<\/a> on cnfuerte.com.<\/p>\n<figure style=\"margin:26px 0;text-align:center;\"><img loading=\"lazy\" decoding=\"async\" style=\"max-width:640px;width:100%;height:auto;display:block;margin:0 auto;border-radius:8px;\" src=\"https:\/\/cnfuerte.com\/wp-content\/uploads\/2026\/07\/disconnector-switch-selection-guide-for-medium-voltage-overhead-lines-product.webp\" alt=\"FUERTE isolating-switch \u2014 official product photo with illustrative scene background (not a real site photo)\" width=\"640\" height=\"360\"\/><\/figure>\n<h2 style=\"margin:42px 0 14px;font-size:1.35em;line-height:1.3;\">FAQ<\/h2>\n<h3 style=\"margin:28px 0 10px;font-size:1.15em;line-height:1.35;\">What is a disconnector switch used for?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7;\">It provides visible isolation for maintenance and sectionalizing on medium-voltage overhead distribution lines, typically without load-breaking unless equipped for that duty.<\/p>\n<h3 style=\"margin:28px 0 10px;font-size:1.15em;line-height:1.35;\">What voltage classes are common for overhead disconnectors?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7;\">15 kV, 27 kV, and 38 kV classes are typical, selected to match system voltage and basic insulation level requirements.<\/p>\n<h3 style=\"margin:28px 0 10px;font-size:1.15em;line-height:1.35;\">How is a disconnector different from a vacuum circuit breaker?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7;\">A breaker interrupts fault current; a disconnector isolates de-energized or specifically rated switching paths and shows visible open position.<\/p>\n<h3 style=\"margin:28px 0 10px;font-size:1.15em;line-height:1.35;\">What continuous current ratings should buyers specify?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7;\">600 A and 900 A are common distribution ratings; match conductor ampacity and future load growth.<\/p>\n<h3 style=\"margin:28px 0 10px;font-size:1.15em;line-height:1.35;\">Do disconnectors need type test reports?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Utilities and EPCs typically require type test evidence aligned with IEEE\/IEC requirements for the target market.<\/p>\n<h3 style=\"margin:28px 0 10px;font-size:1.15em;line-height:1.35;\">When should I choose polymer insulators on a disconnector?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7;\">Polymer housings reduce weight and can improve pollution performance; confirm creepage for site contamination class.<\/p>\n<h2 style=\"margin:42px 0 14px;font-size:1.35em;line-height:1.3;\">References<\/h2>\n<ul style=\"margin:0 0 18px 1.2em;line-height:1.7;\">\n<li><a href=\"https:\/\/standards.ieee.org\/ieee\/C37.46\/4619\/\" rel=\"nofollow noopener\" target=\"_blank\">IEEE C37.46 \u2014 Fuse Disconnecting Switches<\/a><\/li>\n<li><a href=\"https:\/\/www.siemens.com\/en-us\/products\/medium-voltage-power-distribution\/ser-disconnect-switch\/\" rel=\"nofollow noopener\" target=\"_blank\">Siemens SER Disconnect Switch<\/a><\/li>\n<li><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/6579\" rel=\"nofollow noopener\" target=\"_blank\">IEC 62271 \u2014 High-voltage switchgear<\/a><\/li>\n<\/ul>\n<p style=\"margin:0 0 16px;line-height:1.7;\"><strong>Ready to discuss your project?<\/strong> Contact <a href=\"https:\/\/cnfuerte.com\/contact-us\/\">FUERTE engineering support<\/a> with your project parameters and technical requirements.<\/p>\n<\/div>\n<p><script type=\"application\/ld+json\">{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"What is a disconnector switch used for?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"It provides visible isolation for maintenance and sectionalizing on medium-voltage overhead distribution lines, typically without load-breaking unless equipped for that duty.\"}}, {\"@type\": \"Question\", \"name\": \"What voltage classes are common for overhead disconnectors?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"15 kV, 27 kV, and 38 kV classes are typical, selected to match system voltage and basic insulation level requirements.\"}}, {\"@type\": \"Question\", \"name\": \"How is a disconnector different from a vacuum circuit breaker?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"A breaker interrupts fault current; 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