A key coded power connector and a system and method for making key coded power connections are disclosed. A power connector such as a power adapter connector is configured with either a visual keying system, a physical keying system, or both. The physical keying system prevents a user from connecting a host device to a connector of the power source which does not support that host device. The visual keying system provides the user with an early indication that the particular device is not supported by a power source. The user can visually compare a marking key on the host device with the making key on the power connector and determine whether or not the power source is capable of outputting sufficient power to operate the device. The visual and physical keying systems prevents a user from improperly connecting a host device to a power source which does not support that device.