The NEMA L6-30 is used for input on the domestic APC Matrix-UPS, Smart-UPS T models, and Symmetra RM 2-6kva UPS. The NEMA L6-30 receptacle is also used as an output receptacle for supplying 208 VAC in the Matrix-UPS, the Smart-UPS T models, and single phase Symmetra systems (Power Array, RM, LX). It is a locking two-pole, three-wire grounding receptacle with a maximum input of 250V and 30A. When used with APC's UPS models, the receptacle will generally provide either 208V or 240V(depending on the UPS model). This receptacle requires that three connections be made (see diagram below).
X= L1 (Hot)
Y= L2 (Hot)
As previously mentioned, this is a locking receptacle. After insertion, turn the plug clockwise to lock.