The connection device between copper and galvanized piping that prevents corrosion is called a:

The correct answer is the dielectric union. This device is essential in plumbing systems where copper piping is connected to galvanized piping. The primary purpose of a dielectric union is to prevent galvanic corrosion, which occurs when two different metals are in contact with each other in the presence of an electrolyte, such as water.

A dielectric union has an insulating medium between the two different metal surfaces, typically a non-conductive material that prevents electrical continuity. By halting this electrical connection, the union eliminates the risk of corrosion, thereby extending the lifespan of both types of piping.

Understanding this concept is vital for ensuring the integrity of plumbing systems, particularly in scenarios where different metals are inevitably used. This kind of preventive measure is crucial in plumbing installations to maintain water quality and system longevity.