diff --git a/scripts/reclassify_main_heating.py b/scripts/reclassify_main_heating.py
index c958458b4..0d070445e 100644
--- a/scripts/reclassify_main_heating.py
+++ b/scripts/reclassify_main_heating.py
@@ -38,7 +38,14 @@ from scripts.e2e_common import build_engine, load_env
 
 
 def electric_cpsu_for(description: str, main_fuel: Optional[str]) -> Optional[str]:
-    raise NotImplementedError
+    """``"Electric CPSU"`` for a CPSU-boiler override whose property's ``main_fuel``
+    override is electricity, else ``None`` (ADR-0045). ``"Boiler: A/C rated CPSU"``
+    is identical bar the band — the electric/gas split is *fuel*-determined, so this
+    keys on the fuel the guard cannot see; a gas / unknown fuel keeps Gas CPSU
+    (120), and a non-CPSU description is left to the guard."""
+    if "cpsu" in description.lower() and main_fuel == "electricity":
+        return MainHeatingSystemType.ELECTRIC_CPSU.value
+    return None
 
 
 def main_heating_corrections(
@@ -94,6 +101,30 @@ _ENUM_VALUES = text(
     "SELECT e.enumlabel FROM pg_enum e JOIN pg_type t ON t.oid = e.enumtypid "
     "WHERE t.typname = 'main_heating_system'"
 )
+# CPSU boilers still on Gas CPSU, each with its property's main_fuel override —
+# the electric/gas split the description can't carry (ADR-0045).
+_CPSU_ROWS = text(
+    """
+    SELECT mh.property_id AS property_id,
+           lower(mh.original_spreadsheet_description) AS description,
+           mf.override_value AS main_fuel
+    FROM property_overrides mh
+    LEFT JOIN property_overrides mf
+      ON mf.property_id = mh.property_id AND mf.override_component = 'main_fuel'
+    WHERE mh.override_component = 'main_heating_system'
+      AND mh.override_value = 'Gas CPSU'
+      AND lower(mh.original_spreadsheet_description) LIKE '%cpsu%'
+    """
+)
+_CPSU_PROPERTY_UPDATE = text(
+    """
+    UPDATE property_overrides
+       SET override_value = :new_value
+     WHERE property_id = :property_id
+       AND override_component = 'main_heating_system'
+       AND override_value = 'Gas CPSU'
+    """
+)
 
 
 def reclassify(conn: Connection, *, apply: bool) -> tuple[int, set[str]]:
@@ -115,6 +146,21 @@ def reclassify(conn: Connection, *, apply: bool) -> tuple[int, set[str]]:
             conn.execute(_OVERRIDES_UPDATE, params)
             if in_enum:
                 conn.execute(_CACHE_UPDATE, params)
+
+    # Fuel-aware phase: an electric CPSU (fuel-determined, per-property) — update
+    # only the TEXT layer. The description-keyed classifier cache cannot represent
+    # a fuel-dependent value, and "Electric CPSU" is a deferred pgEnum value anyway.
+    for row in conn.execute(_CPSU_ROWS):
+        new_value = electric_cpsu_for(row.description, row.main_fuel)
+        if new_value is None:
+            continue
+        total += 1
+        deferred.add(new_value)
+        if apply:
+            conn.execute(
+                _CPSU_PROPERTY_UPDATE,
+                {"property_id": row.property_id, "new_value": new_value},
+            )
     return total, deferred