diff --git a/datatypes/epc/domain/tests/test_from_site_notes.py b/datatypes/epc/domain/tests/test_from_site_notes.py
index 52598b720..e23d71f57 100644
--- a/datatypes/epc/domain/tests/test_from_site_notes.py
+++ b/datatypes/epc/domain/tests/test_from_site_notes.py
@@ -842,3 +842,20 @@ class TestPasHubUnmappedMainFuel:
         # Act / Assert
         with pytest.raises(UnmappedPasHubLabel, match="Anthracite"):
             EpcPropertyDataMapper.from_site_notes(survey)
+
+    def test_blank_fuel_electric_system_resolves_to_electricity_code(self) -> None:
+        # Arrange — an all-electric system whose surveyed Fuel cell is blank;
+        # the existing electric-system inference must survive normalization and
+        # emit the standard-electricity SAP fuel code (30), not the label.
+        raw = load("pashub_rdsap_site_notes_example1.json")
+        raw["heating_and_hot_water"]["main_heating"]["fuel"] = ""
+        raw["heating_and_hot_water"]["main_heating"][
+            "system_type"
+        ] = "Electric storage heaters"
+        survey = from_dict(PasHubRdSapSiteNotes, raw)
+
+        # Act
+        result = EpcPropertyDataMapper.from_site_notes(survey)
+
+        # Assert
+        assert result.sap_heating.main_heating_details[0].main_fuel_type == 30