Comply with standards: Follow NEC, IEC, or local codes. Use UL/CE-certified parts and record installation details for future inspections. Schedule regular maintenance and inspections to ensure long-term reliability. Each phase in a 3 phase db box carries alternating current (AC) with a phase shift of 120 degrees between them. This allows for more efficient power distribution and balanced loading across the three phases, resulting in better power quality and reduced energy losses. Overall, a 3 phase db box is. In our today electrical wiring installation tutorial, we will show how to wire and install a Three Phase distribution board and Consumer Unit from utility pole to a 3-Phase Energy Meter & 3-Phase Distribution board. Label everything. A distribution board is the combination of protective devices such as Main switch, MCB, MCCB, RCD, RCBO, Isolator, Fuses and Switches etc. A distribution board is also known as main breaker box, electric. Electrolesk A Guide to Practical Electrical Installation Work.