diff --git a/documentation/asciidoc/microcontrollers/debug-probe/introduction.adoc b/documentation/asciidoc/microcontrollers/debug-probe/introduction.adoc
index 3703a213c..eb32d9516 100644
--- a/documentation/asciidoc/microcontrollers/debug-probe/introduction.adoc
+++ b/documentation/asciidoc/microcontrollers/debug-probe/introduction.adoc
@@ -32,7 +32,9 @@ Orange:: TX/SC (Output from Probe)
 Black:: GND
 Yellow:: RX/SD (Input to Probe or I/O)
 
-While the cable with three-pin JST-SH connectors is intended to be used with the https://rpltd.co/debug-spec[standard three-pin connector] which newer Raspberry Pi boards use for the SWD debug port and UART connectors.
+The cable with three-pin JST-SH connectors is intended to be used with the https://rpltd.co/debug-spec[standard three-pin connector] that newer Raspberry Pi boards use for the SWD debug port and UART connectors.
+
+WARNING: When the target is powered from a separate power source or computer, ensure a common reference before connecting signal lines. Either remove power from the target or connect GND between the target and the Raspberry Pi Debug Probe first; you can attach RX, TX, SC, and SD after GND is connected. Potential voltage differences between the two systems can cause damage to the probe.
 
 The Debug Probe has five LEDs, a red LED to indicate power, and four more activity indicator LEDs