Pick the correct terminal block type for your wire size and task. Secure wires by tightening screws to the right amount. Use ferrules to keep wires from fraying. A distribution board or distribution box is where the main power supply is distributed to multiple loads. And all the switching and protective devices are installed in the distribution box. Mastering this process is crucial for. Material preparation: Prepare the required circuit breakers, wires, wiring ties and other materials, and ensure that they meet the design drawings and installation requirements.