A computer model is described which is capable of predicting the maximum current, the ``threshold current'', which can be carried without quenching a Nb&sngbnd;Ti copper composite superconductor undergoing flux jumping. The model utilizes standard equations governing the generation and flow of heat in a wire to predict its voltage‐versus‐time response as a function of current. Calibration of the model for any specific thermal environment is done by means of a simple test procedure involving measurement of the response following the triggering of a flux jump in a small noninductively wound solenoid of one to four layers. The combination of theoretical and experimental techniques indicates the value of adequate copper cross section and good thermal environment, and suggests the superiority of porous fabric or cadmium foil over more conventional interleaving materials, and of thin insulation over the alternatives of thick insulation or none at all.