IEC 61788-5:2013 covers a test method for the determination of copper to superconductor volume ratio of Cu/Nb-Ti composite superconducting wires. This test method and the alternate method in Annex are intended for use with Cu/Nb-Ti composite superconducting wires with a cross-sectional area of 0,1 mm2 to 3 mm2, a diameter of the Nb-Ti filament(s) of 2 micrometers to 200 micrometers, and a copper to superconductor volume ratio of 0,5 or more. The Cu/Nb-Ti composite test conductor discussed in this method has a monolithic structure with a round or rectangular cross-section. This test method is carried out by dissolving the copper with nitric acid. Deviations from this test method that are allowed for routine tests and other specific restrictions are given in this standard. Cu/Nb-Ti composite superconducting wires beyond the limits in the cross-sectional area, the filament diameter and the copper to superconductor volume ratio could be measured with this present method with an anticipated reduction of uncertainty. Other, more specialized, specimen test geometries may be more appropriate for conductors beyond the limits and have been omitted from this present standard for simplicity and to retain low uncertainty. The test method given in this standard is expected to apply to other superconducting composite wires after some appropriate modifications. The copper to superconductor volume ratio of composite superconductors is used mainly to calculate the critical current density of superconducting wires. The test with the method given in this International Standard may be used to provide part of the information needed to determine the suitability of a specific superconductor. Moreover, this method is useful for quality control, acceptance or research testing if the precautions given in this standard are observed. This second edition cancels and replaces the first edition published in 2000. It constitutes a technical revision. The main revisions are the addition of two new annexes, "Uncertainty considerations" (Annex E) and "Uncertainty evaluation in test method of copper to superconductor volume ratio of Cu/Nb-Ti composite superconductors" (Annex F).