Any number of units may be connected in parallel but there are practical cabling and short circuit issues that must addressed for multi-PCS systems. The terminal blocks on the front of the RS40 will accommodate narrow tongue compression lugs up to 2/0 AWG. With 90°C rated cable, this limits the parallel group per cabling feed to three units – see table below. Higher temperature rated cable may permit four units to be parallel connected. Installations requiring more units may use an external combiner to parallel multiple groups. It is the user’s responsibility to ensure that acceptable cable temperatures are maintained under worst case conditions, and that the cables are adequately protected from short circuit currents from the battery and grid. Note: Oztek offers a busbar accessory kit that may be used to conveniently connect RS40 and RS40-PS units in groups of four or less. OZpcs-RS40 Recommended Cable Sizes Assumptions: 45C ambient 40 LFM airflow 90C rated cable   UnitsMax DC (A)AWGMax AC (A)AWG 1756508 215021004 32252/01502