Section — Noldin, Summa of Moral Theology
Section 2. Baptism Received from an Acatholic.
492.
492. Because of Baptism Received from an Acatholic these are irregular: those who, except in a case of extreme necessity, allowed baptism to be conferred on themselves in any way by acatholics.1
a. Acatholics here are understood as heretics and schismatics, whether they exist outside the Catholic Church in good or bad faith.
b. One receiving baptism from an acatholic does not contract irregularity unless by receiving it he commits a grave sin. Therefore those are not irregular who, before the use of reason, receive baptism from an acatholic; nor those who in danger of death have no one else who can baptize them except an acatholic.
1 Cn. 985, 2.