In medium/large PV grid tie system, for more convenient maintenance and reliability, normally the DC combiner is needed between the PV arrays and inverter. Our combiner series were designed for such demand. With this combiner series, the cables between PV arrays and invertor can be save and simplified considerablly. in accordance of the Voltage range of the inverter, the PV boards can be installed in series to meet the input voltage of inveter, and several such series to be installed in parallel, to input into the combiner. The current goes through lightenling protection and breaker equipment, then ouput for connection with inverter. We strongly suggest the users to follow all the necessery safety regulation, take all the safefy masures mentioned in the manual, to lower the possibility of danger, make sure of the personal safety.