Free Trials

Download a free trial to find out which Altium software best suits your needs

How to Buy

Contact your local sales office to get started on improving your design environment


Download the latest in PCB design and EDA software

  • Altium Designer

    Complete Environment for Schematic + Layout

  • CircuitStudio

    Entry Level, Professional PCB Design Tool

  • CircuitMaker

    Community Based PCB Design Tool


    Agile PCB Design For Teams

  • Altium 365

    Connecting PCB Design to the Manufacturing Floor

  • Altium Concord Pro

    Complete Solution for Library Management

  • Octopart

    Extensive, Easy-to-Use Component Database

  • PDN Analyzer

    Natural and Effortless Power Distribution Network Analysis

  • See All Extensions

    World-Renowned Technology for Embedded Systems Development

  • Live Courses

    Learn best practices with instructional training available worldwide

  • On-Demand Courses

    Gain comprehensive knowledge without leaving your home or office

  • A365 Viewer

    View & Share electronic designs in your browser

  • Altium Designer 20

    The most powerful, modern and easy-to-use PCB design tool for professional use


    Annual PCB Design Summit

    • Forum

      Where Altium users and enthusiasts can interact with each other

    • Blog

      Our blog about things that interest us and hopefully you too

    • Ideas

      Submit ideas and vote for new features you want in Altium tools

    • Bug Crunch

      Help make the software better by submitting bugs and voting on what's important

    • Wall

      A stream of events on AltiumLive you follow by participating in or subscribing to

    • Beta Program

      Information about participating in our Beta program and getting early access to Altium tools

    All Resources

    Explore the latest content from blog posts to social media and technical white papers gathered together for your convenience


    Take a look at what download options are available to best suit your needs

    How to Buy

    Contact your local sales office to get started improving your design environment

    • Documentation

      The documentation area is where you can find extensive, versioned information about our software online, for free.

    • Training & Events

      View the schedule and register for training events all around the world and online

    • Design Content

      Browse our vast library of free design content including components, templates and reference designs

    • Webinars

      Attend a live webinar online or get instant access to our on demand series of webinars

    • Support

      Get your questions answered with our variety of direct support and self-service options

    • Technical Papers

      Stay up to date with the latest technology and industry trends with our complete collection of technical white papers.

    • Video Library

      Quick and to-the-point video tutorials to get you started with Altium Designer

    High Voltage PCB Design for Arc Prevention: How to Manage Pads and Traces

    Altium Designer
    |  August 31, 2017

    Growing up, I’d work obsessively on jigsaw puzzles with my grandmother. Like, skipping dinner obsessively. She was a grandmaster of puzzles; you only got to look at the picture once when you took the pieces out. If you needed more than your memory and pattern recognition, that was cheating. Instead of facing the shame of looking at the box, I learned to focus on the shapes of the pieces, and how each fit with its neighbors. That way, not knowing the exact final picture was less paralyzing.

    Laying out traces and pads for a high voltage PCB design reminds me of doing jigsaw puzzles. You have an overall picture in your mind, but the shape of each piece is still important if you want to get the final solution right. There are a couple different aspects to consider for your pads and traces to get the shape just right, especially in high voltage applications.

    Best practices for designing corners on your high voltage board

    You want to avoid any corners and sharp edges or turns on high voltage Printed Bs. For pads, use a smooth, round curve that cuts off the corners. Design the curve with the largest radius you can without losing the necessary surface area.

    When you route the traces, you also want to avoid sharp corners at turns. Instead, use a curved track, again with the largest radius you’ve got space for.

    If you are using solder balls at connection points, you should also specify a minimum radius for the solder balls. Make sure you inform your manufacturer before they quote you for the fabrication, since you may need a larger solder ball than they typically use.

    Solder balls for the socket of a CPU motherboard.
    Small radius solder balls can concentrate the electric field on a high voltage PCB and increase the risk of arcing or corona events.

    Spacing considerations on your high voltage board

    By using curved edges instead of corners, you can use much a smaller spacing between features. According to Sierra Proto Board, direct arcing can occur at ⅓ the distance from a needlepoint as compared with a rounded edge. It’s also three times easier for a needlepoint to generate corona.

    Sierra Proto also has equations to help you estimate your spacing distance based on your operating frequency. Remember that high frequency will arc more easily, so your spacing increases by a recommended factor of 1.12X.

    Once you have your board, make sure that the surface and edges are clean, and all of the conductors are smooth before you power it up. Dirt, rough edges, and scratches can all decrease the arc-over voltage by 70-80%

    Best practices for designing edges on your high voltage board

    Just like edge pieces in a jigsaw puzzle, edges on a Printed Board will need special attention. When the edge of a board is machined or routered, burrs are often left behind on the raw edge. If that happens on a conductive trace, the burr will function like a needlepoint and dramatically increase the risk of arcing.

    To be safe, your layout should set copper traces back from any edges. Use a minimum buffer distance of 0.02 inches between a conductor and the edge. Increase the distance by 0.001 inches for every 100 V the trace will experience at its maximum load.

    Sometimes, you’ve got no choice but to shoehorn a trace in near the edge. In that case, you can use a conformal coat of a high voltage compatible material, like HVPF. The coating allows you to provide additional protection to your PCB out to the edges of the board.

    Connector pads at the edge of a PCB
    Traces and pads near the edge of a high voltage PCB require special design consideration to protect them from machining damage.

    My grandmother will disagree, but mistakes in a Printed Board design are much more serious than mistakes in a jigsaw puzzle. This is why you should make sure that you’re using the best tools possible. An especially helpful feature in design software, like Altium Designer® , is setting your own design rules. That way you don’t have to remember spacing distance and solder ball size while you’re optimizing a layout with only rounded tracks.

    Once you’ve put the puzzles away, Live support at Altium is available to help you learn more about how the best PCB software can help you improve your high voltage PCB design process.

    Have a question about high voltage PCB design for arc prevention? Contact an expert at Altium.


    Check out Altium in action...

    PADS® Logic Exporter

    About Author

    About Author

    PCB Design Tools for Electronics Design and DFM. Information for EDA Leaders.

    most recent articles

    Back to Home