Which of the following options is NOT a Code-compliant method for connecting grounding electrode conductor taps to a common grounding electrode conductor?

The method that is not Code-compliant for connecting grounding electrode conductor taps to a common grounding electrode conductor is soldering. The rationale behind this is that soldering does not create a reliable, strong mechanical connection that is necessary for grounding applications. Grounding systems must ensure continuity and integrity under various environmental conditions, and soldered connections can be susceptible to mechanical failure over time, particularly with thermal expansion, vibration, or corrosion.

In contrast, compression connectors, welding, and mechanical connectors are accepted methods because they provide robust, durable connections that meet the necessary standards for grounding applications. These methods ensure a permanent connection that maintains conductivity and integrity, crucial for the effectiveness of grounding systems. The Code emphasizes the reliability and safety of grounding systems, which is why soldering is not an acceptable method in this context.