Those Sacramentals that consist in constitutive consecrations or blessing produce their effect infallibly, provided no obex stands in the way. THey permanently and infallibly dedicate a person or thing to ALmight God and to the Divine Cult.John L. Paschang, Sacramentals According to the Code of Canon Law. (Washington, D.C.: Catholic University of America, 1925), 34.
Citing various moral theology manuals, Paschang gives a rationale for the infallibility of different types of sacramentals.
