The IEC Standard for Power Distribution Board Design and Layout serves as the global benchmark for ensuring safety, efficiency, and reliability in electrical systems. If you're involved in electrical installation or panel manufacturing, understanding these standards is crucial. What Is a Junction Box? A junction box is primarily used for housing connections between electrical cables. It does not control or distribute power in the same way as distribution or control boxes. Design requirements help you follow important standards like. NOTE The voltage limits for DC applications are under consideration. This second edition cancels and replaces the first edition published in 2012.