Index: firmware/App/Drivers/SafetyShutdown.c
===================================================================
diff -u -rd52eeaec7379650a8cf901f06d3bd8ddf5cb7f06 -r48fa4e359dee8dae08067a7642ea3a8a526949d5
--- firmware/App/Drivers/SafetyShutdown.c	(.../SafetyShutdown.c)	(revision d52eeaec7379650a8cf901f06d3bd8ddf5cb7f06)
+++ firmware/App/Drivers/SafetyShutdown.c	(.../SafetyShutdown.c)	(revision 48fa4e359dee8dae08067a7642ea3a8a526949d5)
@@ -36,8 +36,9 @@
 #define SAFETY_SHUTDOWN_POST_TIMEOUT_MS     500                                     ///< Safety shutdown POST test timeout (in ms).
 #define SAFETY_SHUTDOWN_RECOVERY_TIME_MS    500                                     ///< After safety shutdown POST test, wait this long (in ms) to recover before moving on.
 
-#define MAX_24V_LEVEL_ON_SAFETY_SHUTDOWN    5.0F                                    ///< Maximum voltage on 24V line when safety shutdown asserted.
-#define MIN_24V_LEVEL_ON_SAFETY_RECOVER     22.6F                                   ///< Minimum voltage on 24V line when safety shutdown is recovered.
+#define MAX_24V_LEVEL_ON_SAFETY_SHUTDOWN     5.0F                                   ///< Maximum voltage on 24V line when safety shutdown asserted.
+#define MAX_ISOLATED_24V_LEVEL_ON_SS_EXPIRED 22.6F                                  ///< Maximum voltage on isolated 24V line when watchdog is expired. 10% of 24V.
+#define MIN_24V_LEVEL_ON_SAFETY_RECOVER      22.6F                                  ///< Minimum voltage on 24V line when safety shutdown is recovered.
 
 /// Enumeration of safety shutdown self-test states.
 typedef enum Safety_Shutdown_Self_Test_States
@@ -130,7 +131,7 @@
                 F32 isolatedV24 = getMonitoredLineLevel( MONITORED_LINE_24V_POWER_PRIM_HTR_V );
 
                 // Verify 24V is down when w.d. expired
-                if ( ( v24 > MAX_24V_LEVEL_ON_SAFETY_SHUTDOWN ) || ( isolatedV24 > MAX_24V_LEVEL_ON_SAFETY_SHUTDOWN ) )
+                if ( ( v24 > MAX_24V_LEVEL_ON_SAFETY_SHUTDOWN ) || ( isolatedV24 > MAX_ISOLATED_24V_LEVEL_ON_SS_EXPIRED ) )
                 {
                     SET_ALARM_WITH_2_F32_DATA( ALARM_ID_DG_SAFETY_SHUTDOWN_POST_TEST_FAILED, 1.0, v24 );
                     safetyShutdownSelfTestStatus = SELF_TEST_STATUS_FAILED;