Advantages of High-Voltage Differential Probes and the Limitations of Passive Probes

Directly float the oscilloscope’s ground lead to measure high-voltage signals.

This practice is unsafe and inaccurate. Due to the existence  of parasitic
capacitance between the oscilloscope shell and the earth, it is easy to
cause signal ringing, resulting in serious waveform distortion, which is not recommended for practical use 

Use two passive probes to measure the voltage of two points relative to ground separately, and then use the oscilloscope's math function to subtract and obtain the differential value. 

Although relatively safe, avoiding the risk of direct grounding short
circuits, the measurement accuracy is poor. Due to the delay and
inconsistencies of the two channels, the system's common-mode noise,
making it unsuitable for high-precision situations.

Use a dedicated high-voltage differential probe to directly measure the voltage difference between two points.

This is currently the safest and most accurate method. The probe features high-voltage isolation and high common-mode rejection design internally, allowing direct measurement of signals with high voltage relative to ground. It is also suitable for differential systems that do not share a common ground (such as CAN bus), avoiding the risk of short circuits caused by improper grounding.

The high-voltage differential probe uses a differential input mode and is mainly used in situations where high-voltage floating ground measurements are required. This high-performance high-voltage differential probe features audio-visual alarm functions, a 5MHz bandwidth limit option, and provides better common-mode noise suppression capability. 

Its bandwidth reaches up to 100MHz, with high input impedance and low input capacitance at the input terminals, allowing accurate and high-speed measurement of differential voltage signals, meeting the needs of most testing systems.