When does a 1-phase UPS have to be hardwired?

Single or 1phase uninterruptible power supplies up to 2kVA (2000VA) tend to use a power cord and standard plug. 3kVA and some 4kVA UPS systems (drawing up to 16A) are supplied with blue Commando style plugs. Above this power rating the uninterruptible power supply is hardwired. Below this rating, the UPS system may be converted by the UPS manufacturer or supplier for a hardwired installation and the sockets and power cord re replaced with a plate with terminals.