The phase ended in industrial installations (recommended for this type of facility) are those formed by three different phases. It is normally found in industries, but also can be found in old residential installation. Facilities include three-phase 5-wire cable 1. phase (black or brown cable) provides electricity. 2. The power phase 2 (brown) provides electricity. 3.Phase 3 cable (gray) provides electricity. 4. Neutral (blue wire) is responsible for the electricity back where it came from creating a circle. 5. Physical cable (two colors) protects the energy absorbing phase of their environment, in some cases this fifth wire is not used, but it should be done for safety. 1. In the image-phase power system three-phase power system 2.