Circuit Break - A MacroFab Podcast

MEP EP#288: We have clearance, Clarence

Listen Later

MEP EP#288: We have clearance, Clarence

PCB design rules for clearances

  • Stephen's favorite calculator
  • Clearance and creepage
  • According to the IEC (international electrotechnical commission) a global standards organization
    • Clearance - The shortest path between two conductive parts, or between a conductive part and the bounding surface of the equipment, measured through air
    • Creepage - The shortest path between two conductive parts, or between a conductive part and the bounding surface of the equipment, measured along the surface of the insulation
    • IEC/UL 60950-1 Safety standards - has more in depth information on spacing and how to handle mains
    • IPC2221 generic pcb design rules - Has simple information on spacing vs voltage
    • The creepage requirements depend on
      • insulation material group
        • Comparative Tracking Index (CTI) is used to measure the electrical breakdown (tracking) properties of an insulating material. Tracking is an electrical breakdown on the surface of an insulating material wherein an initial exposure to electrical arcing heat carbonizes the material. The carbonized areas are more conductive than the pristine insulator, increasing current flow, resulting in increased heat generation, and eventually the insulation becomes completely conductive.
          • I 600V
          • II 400 to 600V
          • IIIa 175 to 400V
          • IIIb 100 to 175V
          • pollution degree
            • Degree 1 - no pollution
            • Degree 2 - non-conductive contamination that might temporarily become conductive due to condensation
            • Degree 3 applies to conductive pollution, or to dry non-conductive one which could become conductive due to condensation
            • working voltage
            • Altitude and elevation - Multiply by 1.48
            • Appliance insulation class
              • Functional
              • Basic
              • Supplementary
              • Double Insulation - Double the creepage
              • Reinforced - Double the creepage
              • IPC2221 requirements - Actually tend to be larger
                • External
                • Internal
                • Coated

                  • Stephen’s thoughts on the AND!XOR hardware puzzle

                   

                  ...more
                  View all episodesView all episodes
                  Download on the App Store
                  Circuit Break - A MacroFab PodcastBy MacroFab, Inc.
                  • 4.8
                  • 4.8
                  • 4.8
                  • 4.8
                  • 4.8

                  4.8

                  37 ratings

                  More shows like Circuit Break - A MacroFab Podcast

                  View all
                  The Amp Hour Electronics Podcast by The Amp Hour (Chris Gammell and David L Jones)

                  The Amp Hour Electronics Podcast

                  229 Listeners

                  Embedded by Logical Elegance

                  Embedded

                  189 Listeners

                  All Ears English Podcast by Lindsay McMahon and Michelle Kaplan

                  All Ears English Podcast

                  2,271 Listeners

                  Recording Studio Rockstars by Lij Shaw

                  Recording Studio Rockstars

                  503 Listeners

                  Well There‘s Your Problem by WTYP is Justin Roczniak, November Kelly, Liam McAnderson, and friends.

                  Well There‘s Your Problem

                  1,219 Listeners

                  The Rest Is History by Goalhanger

                  The Rest Is History

                  12,428 Listeners

                  The Carmudgeon Show by Hagerty Media

                  The Carmudgeon Show

                  281 Listeners