Using a cold water pipe as a ground for electrical systems is effective because it is typically in direct contact with the earth, ensuring a reliable grounding path. Metal pipes, like copper or galvanized steel, are preferred for grounding, as plastic pipes do not provide electrical connectivity. The cold water lines are usually interconnected and linked to the water main, which is buried underground, enhancing their grounding capability. In contrast, hot water pipes often have dielectric couplings that break electrical connections, making them less effective for grounding. However, caution is advised, as regulations regarding the use of water pipes for grounding vary by country, and many modern systems utilize plastic piping.