Two prototype binary HTS current leads for superconducting magnets rated for current 7.5 kA are designed and constructed. The HTS part consists of Ag/Bi-2223 tapes. The construction of the current lead is reviewed. Several design considerations are validated with experimental measurements in specially designed and constructed apparatus. A low heat leak cryogenic station is designed, constructed and set-up in order to accommodate thermo-electric tests of resistive conduction cooled current leads for superconducting particle accelerator magnets rated for currents 60 A and 120 A. furthermore, the cryogenic station is tested and its suitability for the tests is verified. A cryogenic station is designed, built and set-up in order to measure the quench propagation in HTS composite current leads. The conditions of quench propagation in composite HTS elements for current leads are successfully reproduced in adiabatic conditions. The transient response of the HTS element (Ag/Bi-2223 tape-stainless steel shunt) subjected to quench is recorded in terms of temperature and voltage time characteristics and analysed.