According to LPI-175, what should be done if the electric service is underground?

The correct answer involves the installation of an arrester, which is a critical component for protecting electrical systems from surges, particularly those caused by lightning. According to LPI-175 guidelines, when the electric service is underground, the risk of lightning strikes inducing surges into the electrical system still exists, even though the service may be lesser exposed than an overhead service. An arrester effectively diverts high-voltage spikes caused by lightning away from the electrical system, protecting equipment and reducing the risk of fire or damage.

The other options do not provide the appropriate means of protection or risk mitigation. While surge protectors are generally useful, in the context of underground services specifically, the focus on arresters is more aligned with industry standards for direct lightning protection. Removing the ground wire is unsafe and goes against best practices, as grounding is essential for safety and system stability. Adding extra grounding rods could be beneficial in some cases, but without the specific action of installing an arrester, the system would still be vulnerable to surges from lightning, rendering it less effective in safeguarding equipment. Therefore, the installation of an arrester remains the most appropriate course of action for underground electric services.