TCM0122180 | Eligibility - miscellaneous: Second adult element (Info)
From HM Revenue & Customs · Tax Credits Manual
In a joint claim, the second adult element of WTC is not payable if
neither customer works 30 hours or more weekly.
However, they are eligible to receive the second adult element of WTC if
the customer or partner is responsible for a child or young person
or
they satisfy the requirements for the disablement element.