ARRL Technician Practice Exam

Which precaution should be taken when installing devices for lightning protection in a coaxial cable feed line?

1. Use plastic casings for all parts

2. Ground all of the protectors to a common plate which is in turn connected to an external ground

3. Use only one lightning protector to save costs

4. Place protectors indoors only

The correct answer is: Ground all of the protectors to a common plate which is in turn connected to an external ground

Grounding all lightning protectors to a common plate that is then connected to an external ground is critical for effective lightning protection in coaxial cable feed lines. This approach ensures that any electrical discharge from lightning strikes is dissipated safely into the ground, minimizing the risk of damage to the equipment and connected devices. By having a common grounding point, it also helps to reduce the potential difference that could arise between different equipment, which can be a significant factor during a lightning event. Using plastic casings or placing protectors indoors may only offer minimal protection and does not address the fundamental issue of grounding, which is essential during a lightning strike. Relying on just one lightning protector might save costs, but it compromises the system's overall protection. Multiple protectors distributed throughout the system and properly grounded are more effective in directing the energy away from sensitive equipment, thus providing comprehensive protection.