The NEMA L14-30 receptacle can be found on the Matrix-UPS, Symmetra Power Array with integrated PDU (SYMSTRF-PD), and Symmetra LX systems. It is a locking 3-pole, 4-wire grounding receptacle rated for either 120 or 240 VAC. There are four connections made to this receptacle:
X and Y are phase conductors
W is a neutral conductor.
G is ground.
This receptacle can deliver 120 VAC from either phase if the plug (L14-30P) is wired to access the neutral, ground and one of the two hot legs on the receptacle. For the receptacle to deliver 240 VAC, the plug must access both hot phases (X and Y) and the ground wire. One purpose this receptacle serves on the Matrix-UPS is to power cord-connected PDUs (Power Distribution Units, blocks of additional outlet receptacles). As previously mentioned, this is a locking receptacle. Once the plug is inserted, turn it to the right to lock it.