How high above the floor must the operating handle of an overcurrent device be installed at maximum?

The correct answer reflects the maximum height requirement for the operating handle of an overcurrent device, which is set at 6 feet 7 inches above the floor. This height is established by electrical codes and standards to ensure accessibility and safety. Such specifications are essential to allow operators to easily access and control the device in an emergency or during routine operations.

Devices like circuit breakers and disconnect switches should be within reach to ensure that they can be quickly and safely operated. Installing the handle at this height balances the need for accessibility for maintenance and operation with safety considerations, avoiding placement that could make the device difficult to access in a timely manner.

The other height options exceed this standard, thus not complying with established regulations for overcurrent device installation. By adhering to the 6 feet 7 inches guideline, installations maintain accessibility while ensuring compliance with safety practices in electrical work.