In Se.C.R.E.T.S. (Segregated Copper Ratio Experiments on Transient Stability), the stability performance under transverse field transient is compared for two Nb3Sn cable-in-conduit conductors which differ only because of the different distribution of the stabilizing copper, either included in the Nb3Sn strand cross section or segregated as bundled copper wires. If the segregated copper is found to be effective for stability purposes, the copper fraction in the Nb3Sn strands can be Substantially reduced, with dramatic cost advantage for the high field fusion magnets. The experiment is assembled in the SULTAN facility at CRPP, with 11 T background field and superimposed transverse pulsed field to generate the transient disturbance. The layout of the conductor, the winding sample and the assembly procedure are described. The instrumentation and the test program are planned to provide results to be easily extrapolated to the ITER conductors.