Here are discussed the experiments with high‐current nanosecond discharges through metal wires and dielectric fibres on NIKE‐3 device (100 kA, 50 ns) and BIN one (250 kA, 100 ns). Discharge regime is investigated as a function of load linear density &mgr; by way of example of glass fibres. While mass is increasing discharge through diode changes from regime mismatched regime with electron beam generation (&mgr; < 4 &mgr;g/cm) through hot spots forming regime (&mgr; = 8–20 &mgr;g/cm) and then to intense radiating skin‐shell regime (&mgr; > 30 &mgr;g/cm). Strong influence of surface condition on metal wires explosion character was found. The explosion of the metal wires heated up to 300–500°C for cleaning the surface was the most stable. The experimental results of the wire explosion were explained by the metal‐plasma transition model. The results of optical measurements of the plasma movement and column instability development during the discharge process are presented. In several experiments simultaneous development of kink and sausage instability was observed. 2D simulation of the sausage instability according to ideal MHD model corresponds well with experiments.