Plug loads may have a primary-secondary relationship. A primary device, such as a computer, operates independently of other (slave) devices. A secondary device, such as a monitor or other peripheral, depends on the operation of other (master) devices. A load-sensing control device should be implemented for such a relationship. It automatically energizes and de-energizes secondary devices based on the “sensed” power load of the primary device(s). Whenever the primary device goes into a power state below a given threshold, the load-sensing control can power down the secondary devices. The sensed (primary) load is typically an electrical outlet or an auxiliary port (e.g., universal serial bus (USB) in the case of a computer).