Oklahoma Electrical Practice Exam

Which color wire indicates the higher voltage to ground in a switch board supplied from a 3-phase, 4 wire delta system?

1. Red

2. Blue

3. Orange

4. Green

The correct answer is: Orange

In a 3-phase, 4-wire delta system, color codes for wires are established to signify their functionality and potential voltage levels. In this context, the orange wire is used to indicate a higher voltage to ground. This designation is prevalent among electrical systems to reduce confusion and enhance safety. Understanding color codes is essential for electricians. The selection of the orange wire for higher voltage signals is based on standard practices within the industry. In a delta system, you often have three phase conductors and a neutral. Each of these wires carries a different potential relative to ground, and the orange wire is specifically meant to identify the phase that operates at a higher voltage, which is crucial when working on or near electrical equipment. By identifying the correct wire color, electricians can ensure they are measuring voltage correctly, servicing the right parts of the system, and staying compliant with safety standards. This knowledge also aids in troubleshooting and understanding the electrical behavior of the circuit, making it an integral part of electrical training and practice.