Quick answer
List only the equipment that must remain powered long enough to save work or shut down safely. Record actual or documented watts, simultaneous load, required time and the communication path used to trigger shutdown.
Planning brief
- Protected device, power supply and measured or documented load.
- Total simultaneous watts plus the exact UPS output and socket arrangement.
- Minimum useful runtime at that load, with battery age and maker assumptions visible.
- USB, network or software support for the exact protected system.
- Order of shutdown and what must restart manually.
- Battery test, replacement, ventilation and end-of-life route.
Hidden trade-offs
Longer runtime adds battery size, weight and replacement cost. Protecting non-essential devices can shorten the useful shutdown window for storage and network equipment.
Sources and boundary
Schneider Electric provides a UK APC UPS selector; Eaton explains UPS concepts in its UPS FAQ and publishes runtime graphs. Treat selector output and curves as product-specific planning evidence, not a guarantee in every condition.
Before you buy
Verify load, output, sockets, communication compatibility, runtime curve, battery replacement route, exact UK model, warranty and returns. Use a competent professional where fixed electrical work is involved.