Briefing notes on carers published by DWP at this page

They say

The Universal Credit award will include a carers element which will continue for as long as the carer provides care for at least 35 hours per week for a severely disabled person. The Universal Credit earnings taper will apply to the award and the overall Universal Credit award will be reduced depending on earnings.

Within Universal Credit claimants will only qualify for a limited capability for work element or a carer element, not both. This reflects the fact that the elements are paid in respect of not being able to work through either a medical condition or by virtue of caring responsibilities. However, households will still be able to get a limited capability for work element for one member and the carer element for the other member.

The Carer’s element will not, in itself, exempt the household from the benefits cap or bring any increase in earnings disregards but it will bring the household into the ‘no conditionality’ group.