How far outby the last open crosscut must trolley and feeder wires and transformers be located?

The requirement for trolley and feeder wires and transformers to be located a specified distance outby the last open crosscut is primarily based on safety regulations intended to reduce the risk of electrical hazards in mining operations. Locating these electrical components at least 15 feet outby the last open crosscut helps to ensure that they are removed from areas that are more likely to be compromised or obstructed, which could increase the potential for accidents or electrical failures.

This distance acts as a buffer zone, promoting a safer environment by preventing electrical components from being placed too close to areas that workers might have access to or that may pose higher risks due to potential mine collapses or other geological instabilities. Adhering to this regulation reflects best practices in mine safety and aids in effective emergency response strategies in the event of an unexpected situation within the mine.

The other options either fall short of this safety distance or exceed it without justification, which can lead to unnecessary risks or non-compliance with safety standards in mining operations. Therefore, the establishment of 15 feet as the minimum distance is considered an essential guideline for ensuring the protection of mine workers and maintaining the integrity of electrical systems used underground.