New-generation high-ﬁeld superconducting magnets pose a challenge relating to the protection of the coil winding pack in the case of a quench. The high stored energy per unit volume calls for a very efﬁcient quench detection and fast quench propagation in order to avoid damage due to overheating. A new protection system called Coupling-Loss Induced Quench (CLIQ) was recently developed and tested at CERN. This method provokes a fast change in the magnet transport current by means of a capac- itive discharge. The resulting change in the local magnetic ﬁeld induces inter-ﬁlament and inter-strand coupling losses which heat up the superconductor and eventually initiate a quench in a large fraction of the coil winding pack. The method is extensively tested on a Nb–Ti single-wire test solenoid magnet in the CERN Cryogenic Lab- oratory in order to assess its performance, optimize its operating parameters, and study new electrical con- ﬁgurations. Each parameter is thoroughly analyzed and its impact on the quench efﬁciency highlighted. Furthermore, an alternative method is also considered, based on a CLIQ discharge through a resistive coil magnetically coupled with the solenoid but external to it. Due to the strong coupling between the external coil and the magnet, the oscillating current in the external coil changes the magnetic ﬁeld in the solenoid strands and thus generates coupling losses in the strands. Although for a given charging voltage this con- ﬁguration usually yields poorer quench performance than a standard CLIQ discharge, it has the advantage of being electrically insulated from the solenoid coil, and thus it can work with much higher voltage.