Standard junction boxes are supplied with disconnecting device + fuse holder base already installed and wired (fuses excluded). Available from 32A up to 250A. The isolating device interrupts the electrical connection if the door is opened. To choose the fuse size, check the data sheets of the fuses you want to use and carry out the necessary derating calculations, taking into account an over-temperature inside the fuse box of approx. 30°K relative to the ambient temperature and that there is no ventilation inside the box.