Abstract: A quick-connect plumbing device for exemplary use in connection of an appliance, such as a water heater, to supply line of a dwelling, among other uses. Preferably, the connection creates a dielectric coupling between the appliance and supply line to disconnect electrical communication between the supply line and appliance. The device typically includes a length of rigid conduit structured to form a sweat solder connection to a cooperating solderable plumbing element at a first end, and to form a threaded connection to a cooperating threaded plumbing element at an opposite second end, with a resilient seal element being carried at the second end. The threaded connection can be formed by an internally-threaded nut axially affixed to the conduit to permit nut rotation to axially compress the seal element between the conduit and the threaded plumbing element.