Does the Dell XPS 8300 (bought and delivered to US) have a dual voltage power supply for usage on US and UK power grids?
More about8300 dual voltage
what does it say on the label
f you see something like 110v-240v it should be fine
If it does ..it will have a small red click over switch on the back marked 110v - 220v
All the best Brett
Ideally it should have no red switch, that indicates an old design with passive PFC. A good unit will have no little red switch, but will say 90-240 V input(something around there) and have active PFC so it will work anywhere in the world.
If it has a little red switch it will still work on the UK grid, its just an older cheaper design.