electric main rings of the house
You should be able to tell from the number and size (rating) of the fuses/trip switches in the consumer unit.

The mains circuit should have a higher rating than the lighting - 30A/32A (UK/EU) vs 10A/15A for the lighting. So you should have 2 32A circuits, 2 15A and a separate 32A with thicker 6 mm core wire for an electric cooker or shower.

Source

To test which is which turn off any sensitive equipment (computers etc.) and plug in a desk lamp to one of the sockets. Remove a fuse or flip the switch. Then test to see if the light works. Repeat for all the sockets until you've identified which are connected to this circuit.

Repeat for the other fuse/breaker.

If in doubt consult an electrician.