An experimental study of the radiation-induced electromotive force effect on mineral-insulated cables has been performed in the framework of the development of magnetic diagnostics for ITER. In this study, six MgO insulated cables (with copper and stainless steel cores) were exposed to the combined neutron-gamma field of the BR2 reactor. The recorded currents between the inner conductors and the sheaths were compared to theoretical predictions based on a Monte Carlo code. Special attention was paid to the dependence of the induced currents upon the environment and even upon the relative position of the cables and the surrounding materials with respect to the radiation source. In accordance with the theoretical predictions, the copper-core cables show significantly higher induced currents than the stainless steel-core cables due to the beta decay of 66Cu formed after neutron capture.