This Easifit Y-Cable Kit with a large sensor, is for systems where the cables are larger than 10mm or where the amps per phase is greater than 71 and less than 200 amps There are two commonly used wiring methods employed during the installation of Solar PV systems, Please view the diagram included in the pictures to see what type of installation you have. If you have a Type 1 system, then you just need to purchase Intuition-pv. If however you have a Type 2 system you need to purchase both an Intuition-pv and the Y-Cable Pack listed here. Type 1 is where the feed from the PV Inverter is connected into a Henley junction block, together with the feed from the grid supply meter, before connection to the Consumer Unit / Distribution Box. Type 2 is where the feed from the PV Inverter is connected straight into the Consumer Unit / Distribution Box. What's In The Box: 1 x Y-Cable, 1 x Large Sensor (<17mm cable, <200A), Installation Instructions