This part of IEC 60320 is applicable to special purpose appliance couplers for household sewing machines. These sewing machine couplers are for a.c. only and have a rated voltage not exceeding 250 V and a rated current not exceeding 2,5 A. The sewing machine couplers may include two or more contacts depending on the control components or circuitry required to operate the sewing machine and may be with or without earthing contact.