Mounting the Box Mark and drill holes → fix box with expansion bolts. Keep box level and stable; use waterproof type if outdoors. Wiring Connections Strip wires → connect to terminals (phase, neutral, ground) → arrange neatly. Ensure tight contact, correct wiring . Learn how to wire a distribution box step by step! This video shows real on-site footage of electrical installation, demonstrating safe and standardized wiring methods used by professionals. A cable. Strictly speaking, the word “Distribution Box (D-box)” can refer to two categories: electrical distribution boxes and septic tank distribution boxes. This article mainly talks about the first one.