Connect and fuse the DUT as in real vehicle, but without alternator and battery. For all devices, both case 1 and case 2 shall be tested. Apply the voltages for each case simultaneously to all relevant power terminals with reversed polarity.-Case 1If the DUT is used in a vehicle in which the alternator circuit is not fused and the rectifier diodes withstand a reversed voltage for 60s, for UN = 12V systems, apply a test voltage UT = (4 ± 0,2)V with reversed polarity simultaneously to all relevant inputs (terminals) of the DUT for a duration of (60 ± 6)s. -Case 2In all other cases, apply the voltage UA (see 16.1 General test conditions) with reversed polarity simultaneously to all relevant inputs (terminals) of the DUT for a duration of (60 ± 6)s. If a test device is protected by a fuse in the electrical distribution system the device must withstand the test currents during the maximal operating times of the fuse as described in 0 ISO 8820, Road vehicles --Fuse-links for the relevant fuse.Protection for reversed voltage by fuse in the electrical distribution system must be agreed upon with the responsible department for electrical architecture.