Square D QO main lugs load center. Plug-on Neutral ready and built with a shielded, copper bus bar that is plated for reliability. Ground bar is included. UL (Underwriter's Laboratories) listed for residential, commercial, and industrial power distribution. QO load centers are tested and listed only for QO circuit breakers. Engineered for fast installation and wire savings. This load center allows up to 34 total circuits.