S.C. Code § 30-7-80
Except as otherwise provided by statute, the recordation of the assignments, satisfactions, releases, contracts in the nature of subordinations, waivers, and extensions of chattel mortgages or other instruments conveying an interest in or creating a lien on personal property must be upon the record of the recorded mortgage or other written instrument, except that the instrument may be recorded elsewhere in the book for the recordation of mortgages should there be no place upon the record of the recorded mortgage or other written instrument sufficient for the recordation of the assignment, satisfaction, release, contract in the nature of subordination, waiver, or extension of the lien, in which event there must be entered on the margin of the recorded mortgage or other written instrument whose assignment, satisfaction, release, contract in the nature of subordination, waiver, or extension has been thus recorded elsewhere an appropriate reference to the recordation, giving the names of the parties to the recordation, the date, and the book and page where the instrument is recorded. In any county where the records are photographed, microphotographed, or filmed, and there is no place upon the record of the recorded mortgage or other written instrument, or upon the margin of the recorded mortgage or other written instrument sufficient for the recordation of the assignments, satisfactions, releases, contracts in the nature of subordinations, waivers, and extensions of chattel mortgages or other instruments, the documents may be separately recorded as other instruments, and notation of the place of the recordation must be entered on the index for the mortgage or other written instrument or in a legible manner in the jacket or other container for the photograph, microphotograph, or film. Any assignment, satisfaction, release, contract in the nature of subordination, waiver, or extension of a chattel mortgage or other instrument conveying an interest in or creating a lien on personal property, to be entitled to be recorded as herein provided must be in writing and witnessed, as mortgages of personal property are required to be witnessed and not probated when it is upon the original mortgage or other instrument itself, but when it is upon a separate piece then it must be probated in the same way as is required for the probating of mortgages of personal property.
S.C. Code § 30-7-80