CSP12 parallel string box can parallel 12 PV strings. It is equipped with a control logic unit to measure main quantities and to generate alarms if needed. One of its main features is the control of the strings' power difference, which is signaled as "out of range current" when exceeding a preset threshold. The string box includes an integrated display to facilitate local maintenance operations and can be equipped with unlock spools for easier installations where this characteristic is required by law.