This guide covers split load vs dual RCD vs RCBO board configurations, circuit arrangement and allocation, BS 7671 labelling requirements, type testing under BS EN 61439, SPD installation, wiring best practice, and the common mistakes found during EICR inspections. A distribution box, sometimes referred to as a panel board, distribution board, or breaker panel, is an essential part of electrical systems that makes it easier to distribute electricity throughout a structure. “ Replaced three separate apps. Understanding the wiring diagram of an electrical panel box is essential for electricians and homeowners alike, as it allows them to troubleshoot any electrical issues, carry out repairs, or make additions to the system. This buyer's guide is designed to give you an overview of distribution boards.