@@ -714,6 +714,7 @@ def load_component_class(component_info):
             "gateway_inverter_serial": {"required": False, "config": "gateway_inverter_serial", "default": None},
             "gateway_evc_automatic": {"required": False, "config": "gateway_evc_automatic", "default": False},
             "gateway_evc_control": {"required": False, "config": "gateway_evc_control", "default": False},
+            "gateway_shared_ct": {"required": False, "config": "gateway_shared_ct", "default": False},
         },
         "phase": 1,
         "can_restart": True,
 
@@ -2896,6 +2896,7 @@
     "gateway_mqtt_host": {"type": "string", "empty": False},
     "gateway_mqtt_port": {"type": "integer", "zero": False},
     "gateway_mqtt_token": {"type": "string", "empty": False},
+    "gateway_shared_ct": {"type": "boolean"},
     # User-maintained log/debug redaction denylist (GH#4770): literal strings to mask wherever a
     # value appears in predbat.log or a debug dump, for anything Predbat cannot recognise as a
     # credential from its own config - an MPAN or account number surfaced by a third-party HA
 
@@ -212,7 +212,7 @@ class GatewayMQTT(ComponentBase):
     # control writes (engine thread) and by acks arriving on the MQTT listener's loop.
     _command_lock = threading.Lock()
 
-    def initialize(self, gateway_device_id=None, mqtt_host=None, mqtt_port=8883, mqtt_token=None, gateway_inverter_serial=None, gateway_evc_automatic=False, gateway_evc_control=False, **kwargs):
+    def initialize(self, gateway_device_id=None, mqtt_host=None, mqtt_port=8883, mqtt_token=None, gateway_inverter_serial=None, gateway_evc_automatic=False, gateway_evc_control=False, gateway_shared_ct=False, **kwargs):
         """Initialize gateway configuration and build MQTT topic strings.
 
         Args:
@@ -228,11 +228,16 @@ def initialize(self, gateway_device_id=None, mqtt_host=None, mqtt_port=8883, mqt
             gateway_evc_control: When True (requires gateway_evc_automatic), check once per minute whether
                 the current time falls inside a planned car-charging window and send RemoteStartTransaction
                 plus SetChargingProfile on window entry, or RemoteStopTransaction on window exit.
+            gateway_shared_ct: When True, several inverters share one grid CT clamp, so each reports the
+                same grid and load power. Only the first inverter's readings are then used, so the
+                house's grid and load are not counted once per inverter. Off by default, where each
+                inverter is taken to have its own clamp and the readings are summed.
             **kwargs: Additional keyword arguments (ignored).
         """
         self.gateway_device_id = gateway_device_id
         self.gateway_evc_automatic = bool(gateway_evc_automatic)
         self.gateway_evc_control = bool(gateway_evc_control)
+        self.gateway_shared_ct = bool(gateway_shared_ct)
         self.mqtt_host = mqtt_host
         self.mqtt_port = mqtt_port
         self.mqtt_token = mqtt_token
@@ -1368,6 +1373,12 @@ def automatic_config(self):
         self.set_arg("soc_max", soc_max_entities)
         self.set_arg("battery_power", battery_power_entities)
         self.set_arg("pv_power", pv_power_entities)
+        # Inverters sharing one grid CT clamp each report the same grid and load reading, so they must
+        # not be summed. Same "single source + zeros" pattern as gecloud.py's ge_cloud_automatic_shared_ct.
+        if self.gateway_shared_ct and num_inverters > 1:
+            self.log("Info: GatewayMQTT: Multiple inverters sharing a single CT clamp (gateway_shared_ct) — using first inverter only for grid and load measurements")
+            grid_power_entities = grid_power_entities[:1] + [0 for _ in range(num_inverters - 1)]
+            load_power_entities = load_power_entities[:1] + [0 for _ in range(num_inverters - 1)]
         self.set_arg("grid_power", grid_power_entities)
         self.set_arg("load_power", load_power_entities)
         self.set_arg("charge_rate", charge_rate_entities)
 
@@ -878,6 +878,7 @@ def _make_gateway(self):
         gw.gateway_inverter_serial = []
         gw.gateway_evc_automatic = False
         gw.gateway_evc_control = False
+        gw.gateway_shared_ct = False
         gw._dashboard_calls = {}
 
         def capture_set_arg(key, value):
@@ -1606,6 +1607,7 @@ def _make_gateway(self):
         gw.gateway_inverter_serial = []  # default: no serial filter
         gw.gateway_evc_automatic = False
         gw.gateway_evc_control = False
+        gw.gateway_shared_ct = False
 
         def capture_set_arg(key, value):
             gw._args[key] = value
@@ -1826,6 +1828,76 @@ def test_multi_inverter_battery_args_have_one_entry_per_inverter(self):
         assert gw._args["battery_rate_max"] == [f"sensor.{base0}_battery_rate_max", f"sensor.{base1}_battery_rate_max"]
         assert gw._args["inverter_time"] == [f"sensor.{base0}_inverter_time", f"sensor.{base1}_inverter_time"]
 
+    def _two_inverter_status(self):
+        """Two primary inverters with no EMS or Gateway coordinating them."""
+        status = pb.GatewayStatus()
+        status.device_id = "pbgw_multi"
+        status.firmware = "1.0.0"
+        status.schema_version = 1
+        self._make_inverter(status, serial="CE2223G800", primary=True)
+        self._make_inverter(status, serial="CE2225G400", primary=True)
+        return status
+
+    def test_multi_inverter_grid_and_load_power_are_summed_by_default(self):
+        """Without gateway_shared_ct each inverter's grid and load power is bound, as each has its own CT clamp."""
+        gw = self._make_gateway()
+        gw._last_status = self._two_inverter_status()
+        gw.automatic_config()
+
+        base0 = f"{gw.prefix}_gateway_23g800"
+        base1 = f"{gw.prefix}_gateway_25g400"
+        assert gw._args["grid_power"] == [f"sensor.{base0}_grid_power", f"sensor.{base1}_grid_power"]
+        assert gw._args["load_power"] == [f"sensor.{base0}_load_power", f"sensor.{base1}_load_power"]
+
+    def test_shared_ct_uses_first_inverter_for_grid_and_load_power(self):
+        """gateway_shared_ct binds grid and load power to the first inverter only, with zeros for the rest.
+
+        Two inverters on one CT clamp both report the same grid and load reading, so summing them doubles it.
+        The battery and PV args stay per inverter - those are measured by each inverter itself.
+        """
+        gw = self._make_gateway()
+        gw.gateway_shared_ct = True
+        gw._last_status = self._two_inverter_status()
+        gw.automatic_config()
+
+        base0 = f"{gw.prefix}_gateway_23g800"
+        base1 = f"{gw.prefix}_gateway_25g400"
+        assert gw._args["grid_power"] == [f"sensor.{base0}_grid_power", 0]
+        assert gw._args["load_power"] == [f"sensor.{base0}_load_power", 0]
+        assert gw._args["battery_power"] == [f"sensor.{base0}_battery_power", f"sensor.{base1}_battery_power"]
+        assert gw._args["pv_power"] == [f"sensor.{base0}_pv_power", f"sensor.{base1}_pv_power"]
+        assert gw._args["num_inverters"] == 2
+        logged = " ".join(str(call) for call in gw.log.call_args_list)
+        assert "sharing a single CT clamp" in logged
+
+    def test_shared_ct_has_no_effect_on_a_single_inverter(self):
+        """With one inverter there is nothing to double, so gateway_shared_ct changes nothing."""
+        gw = self._make_gateway()
+        gw.gateway_shared_ct = True
+        gw._last_status = self._basic_status()
+        gw.automatic_config()
+
+        base = f"{gw.prefix}_gateway_456789"
+        assert gw._args["grid_power"] == [f"sensor.{base}_grid_power"]
+        assert gw._args["load_power"] == [f"sensor.{base}_load_power"]
+
+    def test_shared_ct_is_read_from_the_component_argument(self):
+        """initialize() takes gateway_shared_ct from apps.yaml and defaults it to off."""
+        from gateway import GatewayMQTT
+        from unittest.mock import MagicMock
+
+        gw = GatewayMQTT.__new__(GatewayMQTT)
+        gw.base = MagicMock()
+        gw.args = {}
+        gw.initialize(gateway_device_id="pbgw_test", mqtt_host="mqtt.example", mqtt_token="token")
+        assert gw.gateway_shared_ct is False
+
+        gw = GatewayMQTT.__new__(GatewayMQTT)
+        gw.base = MagicMock()
+        gw.args = {}
+        gw.initialize(gateway_device_id="pbgw_test", mqtt_host="mqtt.example", mqtt_token="token", gateway_shared_ct=True)
+        assert gw.gateway_shared_ct is True
+
     # ------------------------------------------------------------------
     # Secondary (cloud) and unsupported feature args
     # ------------------------------------------------------------------
@@ -3208,6 +3280,7 @@ def _make_gateway(self):
         gw.gateway_inverter_serial = []
         gw.gateway_evc_automatic = False
         gw.gateway_evc_control = False
+        gw.gateway_shared_ct = False
         gw._configured_ev_chargers = frozenset()
 
         def capture_set_arg(key, value):
 
@@ -613,6 +613,12 @@ See also **ge_cloud_automatic_split_ct** which takes priority over this setting
 Use this to override automatic shared-CT detection if Predbat incorrectly identifies your system as sharing a CT clamp (e.g. when duplicate meter serials are reported by the cloud API but the inverters actually have separate CT clamps).
 This setting takes priority over **ge_cloud_automatic_shared_ct** if both are set.
 
+- **gateway_shared_ct** - Optional, defaults to false. The equivalent of **ge_cloud_automatic_shared_ct** for inverters controlled through the Predbat Gateway.
+When set to `true`, Predbat will treat multiple inverters as sharing a single physical CT clamp for grid and load measurement,
+so only the first inverter's grid and load power readings are used (the rest are zeroed out), preventing double-counting of grid import/export and house load.
+Use this if you have two or more inverters connected to a single CT clamp with no EMS or Gateway coordinating them. The Predbat Gateway does not detect a shared CT automatically.
+Battery and solar readings are unaffected and are still taken from each inverter.
+
 - **ge_cloud_automatic_split_pv** - Optional, defaults to false. When set to `true`, Predbat will also include any standalone PV-only inverters (e.g. a GivEnergy AC-coupled PV inverter with no battery attached) in **pv_today** and **pv_power**, in addition to the battery inverters.
 Use this if you have a separate PV-only inverter alongside your battery inverter(s) and want its solar generation included in Predbat's totals. Leave this off (the default) if your battery inverters already report all of your solar generation, to avoid duplicating or including unwanted readings.