What is the proper length for a bonded jumper?

A bonded jumper's proper length is crucial for both functionality and safety in electrical wiring and grounding applications. The correct choice emphasizes that the jumper should be "as short as practical but long enough for free movement." This balance ensures that while the jumper can effectively engage with the necessary components, it does not exert undue strain on connections or components, which can occur if it is excessively flexible or long. Additionally, a properly sized jumper helps to minimize resistance in the electrical circuit, which can lead to more efficient operation of the equipment.

Lengthening a jumper without reason (as suggested in the first choice) could introduce unnecessary resistance and increase the risk of physical damage or interference. Conversely, making it excessively short (as in the fourth choice) could restrict movement and potentially lead to mechanical or electrical failure. The precise measurement of one foot (as mentioned in the third choice) does not apply universally, since the required length of a jumper can vary based on the specific application and equipment design. Therefore, the importance of practicality combined with the need for free movement makes the second option the most appropriate response.