diff --git a/homeassistant/components/kostal_plenticore/sensor.py b/homeassistant/components/kostal_plenticore/sensor.py
index fbbfb03fb3e..67de34f2fce 100644
--- a/homeassistant/components/kostal_plenticore/sensor.py
+++ b/homeassistant/components/kostal_plenticore/sensor.py
@@ -17,6 +17,7 @@ from homeassistant.components.sensor import (
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import (
     PERCENTAGE,
+    EntityCategory,
     UnitOfElectricCurrent,
     UnitOfElectricPotential,
     UnitOfEnergy,
@@ -747,6 +748,15 @@ SENSOR_PROCESS_DATA = [
         state_class=SensorStateClass.TOTAL_INCREASING,
         formatter="format_energy",
     ),
+    PlenticoreSensorEntityDescription(
+        module_id="scb:event",
+        key="Event:ActiveErrorCnt",
+        name="Active Alarms",
+        entity_category=EntityCategory.DIAGNOSTIC,
+        entity_registry_enabled_default=False,
+        icon="mdi:alert",
+        formatter="format_round",
+    ),
     PlenticoreSensorEntityDescription(
         module_id="_virt_",
         key="pv_P",