The PM-360 panel are three current coils. These coils measure the current draw on the three main power lines in a system. It is recommended that these coils be mounted securely to the base of the rack or if rings are provided, tie wrapped to power cables. Once mounted the individual mains cables can be passed through the hole in each current coil. It is recommended that only one main cable be passed through the coils however multiple cables can be used only if the phase and current direction being measured are the same. For example three input cables from phase A input may pass through a coil but two cables from phase A and one cable from phase B may not. Mixing phases or directions will result in incorrect current readings. Three unit rack space. Three separate voltage readouts. Three separate current readouts.