Powercon is the trade name for a locking 3 pole AC mains connector produced by Neutrik inc.
Powercon connectors come in two versions, with 20 and 32 ampere capacity.
Though similar in appearance to a Neutrik Speakon connector they are keyed differently and do not mate.
Neutrik - Industrial - powerCON
It's important to note that the Powercon connectors do not have a breaking capacity. This means they are not intended to be disconnected while under load. Doing so may result in arcing on the connector which could lead to a catastrophic failure.