What is the difference between E2-1-15 and OCPD-3-15?

The E2 is single-phase and the OCPD is 3-phase, the main difference between the two would lie in the number of electrical conductors or phases they are designed to handle. E2-1-15 (Single Phase): Single-phase systems are typically used in residential and lighter commercial applications. They consist of two conductors: one phase and one neutral. This system might be less expensive and simpler but can be less efficient for powering heavy-duty industrial equipment. OCPD-3-15 (Three Phase): Three-phase systems are commonly found in industrial environments and large commercial buildings. They consist of three or more conductors, usually three live wires and possibly a neutral wire. Three-phase systems can deliver more continuous power and are more suitable for heavy loads.