Which method is NOT a way to provide ground continuity back to the service panel?

The method of adding extra grounded conductors is not an accepted way to provide ground continuity back to the service panel. Grounding practices are governed by electrical codes, which require specific methods to ensure safety and compliance.

The existing methods mentioned in the other choices adhere to proper grounding techniques established in the National Electrical Code (NEC). Specifically, having two hot conductors and one neutral can work in a three-phase system where the neutral provides a return path and is grounded at the service panel. Four conductor feeders with an equipment grounding conductor utilizes a dedicated ground wire that safely connects back to the panel, ensuring reliable fault current paths. Three conductor feeders that use grounding via conduit also ensure that an effective ground path is maintained through the conductive material of the conduit, providing additional safety.

In contrast, simply adding extra grounded conductors does not fulfill the requirements for ensuring proper ground continuity back to the service panel. It could lead to confusion, improper connections, or break in the continuity of the grounding system, which is critical for overall electrical safety.