diff --git a/Firmware/Marlin_main.cpp b/Firmware/Marlin_main.cpp
index cfd73292..e984f821 100644
--- a/Firmware/Marlin_main.cpp
+++ b/Firmware/Marlin_main.cpp
@@ -195,6 +195,7 @@
 // M84  - Disable steppers until next move,
 //        or use S<seconds> to specify an inactivity timeout, after which the steppers will be disabled.  S0 to disable the timeout.
 // M85  - Set inactivity shutdown timer with parameter S<seconds>. To disable set zero (default)
+// M86  - Set safety timer expiration time with parameter S<seconds>; M86 S0 will disable safety timer
 // M92  - Set axis_steps_per_unit - same syntax as G92
 // M104 - Set extruder target temp
 // M105 - Read current temp
@@ -493,6 +494,7 @@ const int sensitive_pins[] = SENSITIVE_PINS; // Sensitive pin list for M42
 static unsigned long previous_millis_cmd = 0;
 unsigned long max_inactive_time = 0;
 static unsigned long stepper_inactive_time = DEFAULT_STEPPER_DEACTIVE_TIME*1000l;
+static unsigned long safetytimer_inactive_time = DEFAULT_SAFETYTIMER_TIME_MINS*60*1000ul;
 
 unsigned long starttime=0;
 unsigned long stoptime=0;
@@ -5439,6 +5441,15 @@ Sigma_Exit:
         max_inactive_time = code_value() * 1000;
       }
       break;
+#ifdef SAFETYTIMER
+	case 86: // M86 - set safety timer expiration time in seconds; M86 S0 will disable safety timer
+	  //when safety timer expires heatbed and nozzle target temperatures are set to zero
+	  if (code_seen('S')) {
+	    safetytimer_inactive_time = code_value() * 1000;
+		safetyTimer.start();
+	  }
+	  break;
+#endif
     case 92: // M92
       for(int8_t i=0; i < NUM_AXIS; i++)
       {
@@ -7422,18 +7433,20 @@ void handle_status_leds(void) {
 
 #ifdef SAFETYTIMER
 /**
- * @brief Turn off heating after 30 minutes of inactivity
+ * @brief Turn off heating after safetytimer_inactive_time milliseconds of inactivity
  *
  * Full screen blocking notification message is shown after heater turning off.
  * Paused print is not considered inactivity, as nozzle is cooled anyway and bed cooling would
  * damage print.
+ *
+ * If safetytimer_inactive_time is zero, feature is disabled (heating is never turned off because of inactivity)
  */
 static void handleSafetyTimer()
 {
 #if (EXTRUDERS > 1)
 #error Implemented only for one extruder.
 #endif //(EXTRUDERS > 1)
-    if ((PRINTER_ACTIVE) || (!degTargetBed() && !degTargetHotend(0)))
+    if ((PRINTER_ACTIVE) || (!degTargetBed() && !degTargetHotend(0)) || (!safetytimer_inactive_time))
     {
         safetyTimer.stop();
     }
@@ -7441,7 +7454,7 @@ static void handleSafetyTimer()
     {
         safetyTimer.start();
     }
-    else if (safetyTimer.expired(1800000ul)) //30 min
+    else if (safetyTimer.expired(safetytimer_inactive_time))
     {
         setTargetBed(0);
         setTargetHotend(0, 0);
diff --git a/Firmware/variants/1_75mm_MK2-RAMBo10a-E3Dv6full.h b/Firmware/variants/1_75mm_MK2-RAMBo10a-E3Dv6full.h
index d366d429..c7e9e59e 100644
--- a/Firmware/variants/1_75mm_MK2-RAMBo10a-E3Dv6full.h
+++ b/Firmware/variants/1_75mm_MK2-RAMBo10a-E3Dv6full.h
@@ -422,6 +422,10 @@ THERMISTORS SETTINGS
 
 #define END_FILE_SECTION 10000 //number of bytes from end of file used for checking if file is complete
 
+// Safety timer
+#define SAFETYTIMER
+#define DEFAULT_SAFETYTIMER_TIME_MINS 30
+
 #define M600_TIMEOUT 600  //seconds
 
 #ifndef SNMM
diff --git a/Firmware/variants/1_75mm_MK2-RAMBo13a-E3Dv6full.h b/Firmware/variants/1_75mm_MK2-RAMBo13a-E3Dv6full.h
index df676383..022c3293 100644
--- a/Firmware/variants/1_75mm_MK2-RAMBo13a-E3Dv6full.h
+++ b/Firmware/variants/1_75mm_MK2-RAMBo13a-E3Dv6full.h
@@ -422,6 +422,10 @@ THERMISTORS SETTINGS
 
 #define END_FILE_SECTION 10000 //number of bytes from end of file used for checking if file is complete
 
+// Safety timer
+#define SAFETYTIMER
+#define DEFAULT_SAFETYTIMER_TIME_MINS 30
+
 #define M600_TIMEOUT 600  //seconds
 
 #ifndef SNMM
diff --git a/Firmware/variants/1_75mm_MK25-RAMBo10a-E3Dv6full.h b/Firmware/variants/1_75mm_MK25-RAMBo10a-E3Dv6full.h
index c7e1421b..d07ab986 100644
--- a/Firmware/variants/1_75mm_MK25-RAMBo10a-E3Dv6full.h
+++ b/Firmware/variants/1_75mm_MK25-RAMBo10a-E3Dv6full.h
@@ -106,6 +106,7 @@
 
 // Safety timer
 #define SAFETYTIMER
+#define DEFAULT_SAFETYTIMER_TIME_MINS 30
 
 // Filament sensor
 #define PAT9125
diff --git a/Firmware/variants/1_75mm_MK25-RAMBo13a-E3Dv6full.h b/Firmware/variants/1_75mm_MK25-RAMBo13a-E3Dv6full.h
index a8f07916..d019c758 100644
--- a/Firmware/variants/1_75mm_MK25-RAMBo13a-E3Dv6full.h
+++ b/Firmware/variants/1_75mm_MK25-RAMBo13a-E3Dv6full.h
@@ -106,6 +106,7 @@
 
 // Safety timer
 #define SAFETYTIMER
+#define DEFAULT_SAFETYTIMER_TIME_MINS 30
 
 // Filament sensor
 #define PAT9125
diff --git a/Firmware/variants/1_75mm_MK3-EINSy10a-E3Dv6full.h b/Firmware/variants/1_75mm_MK3-EINSy10a-E3Dv6full.h
index d78a737c..2cf61d55 100644
--- a/Firmware/variants/1_75mm_MK3-EINSy10a-E3Dv6full.h
+++ b/Firmware/variants/1_75mm_MK3-EINSy10a-E3Dv6full.h
@@ -130,6 +130,7 @@
 
 // Safety timer
 #define SAFETYTIMER
+#define DEFAULT_SAFETYTIMER_TIME_MINS 30
 
 // Filament sensor
 #define PAT9125