The input to the scope can accept up to 600 VRMS CAT II or 300 VRMS CAT III BNC shell to earth ground, 1200 VRMS CAT II between any two channel commons with each of the channel commons not being more than +/- 600 VRMS from earth ground. The P2220 probe also provides floating measurement capability up to 30 VRMS with TPS2000 Series oscilloscopes only. (Note: Do not float with TDS2000, TDS1000 or TDS200 Series oscilloscopes.) The max input voltage for the P2220 is 300 V CAT II. The Maximum Voltage Between Reference Lead and Earth Ground is 30 VRMS. The float voltage must be subtracted from the tip to earth ground voltage. For example, if the reference lead is floated to 30 VRMS, the tip voltage to the reference lead is limited to 270 VRMS. Floating the reference lead higher than 30 Vrms is possible with the P5120 which can floated up to 600 V CAT II.