KYN28A -12 AC metal closed switching equipment (hereinafter referred to as switch cabinet) is a three-phase AC 50Hz, rated voltage 12kV single bus and bus segmented system in-house power distribution device. It is suitable for power supply systems in-house such as power plants, substations and airports, terminals, factories and mining enterprises, hotels, financial high-rises and civil buildings, and is used for receiving, distributing electricity and monitoring and protecting the power grid. This product conforms to GB3906, DL/T404 standard. Passed the national high-voltage electrical quality supervision and testing center all type test, and passed the anti-internal fault arc test. It is a high-performance power distribution device with the function of preventing misoperation of circuit breakers, preventing load push-pull trolleys, preventing live-load edging of ground switches, preventing power transmission when ground ingressing in ground positions, and preventing misenters of live spaces (referred to as five-proof). Switch cabinet main switch mainly using the company's production of CV1, CV2 in the high-voltage vacuum circuit breaker, with a long service life, high breaking capacity, frequent operation, safe and reliable operation and so on.