26 mm 2 (10 AWG) ground wire must be used, and in all other markets a 6 mm 2 must be used. On the US market, a 5. The neutral conductor is typically the grounded conductor connected to the system's neutral point, carrying current under normal operation. Grounding electrode conductors must be connected at accessible points from the load end of service conductors, with specific rules for outdoor transformers and. Power from factory ground must be installed by a qualified electrician. The basic rule achieves this through an equipment grounding jumper; four exceptions. The correct connection method of Distribution box grounding wire mainly includes the following steps: 1. 30 unless the transformer's primary supply is from a 277V or 480V system or an ungrounded system [250. Systems over 50V are a different story.