The IEC 60446 standard, “Basic and Safety Principles for Man-Machine Interface, Marking, and Identification,” establishes global guidelines for identifying electrical equipment terminals, conductors, and wiring colors. This is an internal LLNL standard meant to guide the design of new facilities, facility modifications, and. The fundamental purpose of wire number marking is to **clarify the function, ownership and connection relationship of wires**, avoid confusion or misoperation, and must meet the following 5 principles: 1. **Uniqueness**: All wire numbers in the same power distribution cabinet (or the same. Purpose – This Article is about all electrical equipment numbering system, Electrical Panel Numbering System, Electrical Wire Numbering System, Electrical Relay Numbering System, Electrical Drawing Numbering System, Electrical Schematic Numbering System, Electrical Cable Numbering Systems. The wire number rules are as follows: 1. Three-phase Power Supply Identification - **Three-phase Live Wires**: Represented by **L1, L2, L3** (or **U, V, W**), corresponding to the phase sequence of the three-phase power supply. - **Ground Wire**:. The IEC (International Electrotechnical Commission) and BS 7671 (British Standard for Electrical Installations) both provide essential requirements for electrical installations, including those for fuse boards like garage unit, consumer unit and distribution board. The purpose of this standard is to.