When connecting conductors of dissimilar metals, they must only be intermixed if the device is _____ for the intended purpose.

The correct answer is that conductors of dissimilar metals may only be intermixed if the device is identified for the intended purpose. This is because "identified" in the context of the National Electrical Code (NEC) refers to equipment or materials that have been recognized and suitable for a specific application, ensuring compatibility and safety in electrical installations. When different metals are combined, they can be susceptible to galvanic corrosion, leading to potential system failure if not used appropriately. Thus, the NEC requires that any such intermixing should be based on a clear identification of compatibility.

"Approved" refers to devices that have been evaluated and accepted by a recognized testing laboratory, but it does not specifically address their identification for use with dissimilar metals. "Standardized" implies that a device meets certain predefined standards, which may not necessarily direct relate to the intermixing of different metals. "Universal" typically describes items that can be used across a wide range of applications, but again, this does not focus specifically on the necessary identification for intermixing conductors of dissimilar metals. This distinction reinforces the importance of using identified devices to ensure safety and compliance in electrical installations.