600Y/347 V three-phase wye service

600Y/347 V is one of the popular wye secondary voltages, along with 208Y/120 and 480Y/277. In a wye connection one end of each winding is tied together to form the neutral, which is usually grounded, so the service supplies both line-to-line and line-to-neutral voltages. When loads are unbalanced, the neutral returns the imbalance current to the source, so phase voltages stay well balanced. The ground reference also lets ground faults be detected and cleared quickly. The drawback of a grounded wye is that it needs four conductors, while delta needs only three. Surge protective devices come in a 347/600 three-phase wye rating under the 600Y voltage code. For wye systems they protect line-to-neutral, line-to-ground, neutral-to-ground and line-to-line.

<!-- review notes

• sentence 5: support check: partial - Passages show 347/600 wye availability and the 600Y code protection modes for three-phase wye (L-N, L-G, N-G, L-L), but the link between 'surge protective devices' catalog and the 347/600 under 600Y code is implied rather than explicit. -->