Floating the scope is a really bad idea; never float the scope, never cut the ground. Doing this will result in poor accuracy, possible damage to the scope and/or the device under test (DUT), the ungrounded oscilloscope case could actually become a shock hazard. To float the scope, the user cuts the ground lead in the power cord. This allows the case of the oscilloscope to float to the voltage present on the probe ground lead and breaks any ground loop with the circuit under test. Every oscilloscope manufacturer warns against this practice in their instruction manuals. The purpose of the ground wire is to protect the user from a shock hazard if an insulation fault were to occur in the primary wiring of the oscilloscope. It also serves as the discharge path for radiated EMI created within the scope. When cut, the scope may emit EMI which interferes with the measurement. If the reference voltage connected to the probe ground lead is high enough, the user risks a serious shock hazard if they should touch any of the conductive surfaces of the scope, including the ground leads of other probes. This is often the case when measuring the primary circuits in off-line switch mode converters. Of course, this technique is limited to single channel operation, as all of the scope channels are referenced to the same potential of the case ground. It also eliminates the ability to externally trigger the oscilloscope from ground referenced control circuits, and connection to printers and computers through interfaces such as GPIB.