New York State Master Electrician Practice Exam

On a 4 wire, delta connected phase system, which conductor must be marked in orange or another effective means?

1. The neutral conductor

2. The conductor with lower phase voltage to ground

3. The conductor with higher phase voltage to ground

4. The ground conductor

The correct answer is: The conductor with higher phase voltage to ground

In a 4 wire, delta connected phase system, the correct procedure is to mark the conductor with the higher phase voltage to ground in orange or another effective means. This marking is crucial for safety and proper identification of electrical conductors within the system. Typically, in a delta configuration, there are three phase conductors and a neutral conductor. The conductor that has the highest phase voltage to ground is the one that poses a greater risk of electrical shock or equipment damage in case of accidental contact. By marking this particular conductor distinctly, it alerts electricians and maintenance personnel to exercise additional caution when working near it. This standard practice helps prevent potential accidents that could arise due to misunderstanding the voltage levels present on each conductor. The other conductors in the system, including the ground conductor, do not require the same level of marking because they do not pose a similar risk or are not as critical for the identification of voltage levels in the context of safety. Marking the conductor with the highest phase voltage to ground is an established safety measure that aligns with industry standards and promotes safer work environments.