You don't need it in a "triangle"/"delta" wiring, but you need it in a "star"/"Y" - https://www.electronicshub.org/comparison-star-delta-connections/ https://ww

You don't need it in a "triangle"/"delta" wiring, but you need it in a "star"/"Y" - https://www.electronicshub.org/comparison-star-delta-connections/ https://www.electronicshub.org/comparison-star-delta-connect... PE is protective earth, grounding wire. Usually you need PE and neutral lines separate for FID (GFCI) protection.