diff --git a/datatypes/epc/domain/epc_property_data.py b/datatypes/epc/domain/epc_property_data.py
index 17437f6f..895e4ab3 100644
--- a/datatypes/epc/domain/epc_property_data.py
+++ b/datatypes/epc/domain/epc_property_data.py
@@ -370,7 +370,12 @@ class SapEnergySource:
     wind_turbines_terrain_type: str  # int in API, str (e.g. "Suburban") in site notes
     electricity_smart_meter_present: bool
 
-    pv_connection: Optional[Union[int, str]] = None  # int from API; str from site notes
+    # gov-API enum (int): 0 = no PV, 1 = PV present but NOT connected to the
+    # dwelling's own electricity meter (communal / separately metered), 2 = PV
+    # connected to the dwelling's meter. Per RdSAP 10 §11.1 / SAP 10.2 Appendix M,
+    # PV is credited to the dwelling's SAP only when connected (== 2); see
+    # `_pv_connected_to_dwelling_meter` in cert_to_inputs. str from site notes.
+    pv_connection: Optional[Union[int, str]] = None
     photovoltaic_supply: Optional[PhotovoltaicSupply] = None
     photovoltaic_arrays: Optional[List[PhotovoltaicArray]] = None
     wind_turbine_details: Optional[WindTurbineDetails] = None