A power supply system includes an AC power line with an uninterruptible power supply (UPS) device coupled to receive power from the AC power line. The UPS includes control circuitry that couples power conversion circuitry of the UPS to the AC power line when the available AC power is acceptable. The power supply system also includes a second UPS device coupled to receive power from the AC power line. The second UPS includes a timer delay, such that the control circuitry is configured to couple power conversion circuitry to the AC power line when the available AC power is acceptable, and upon expiration of the timer.