diff --git a/src/power_grid_model/validation/rules.py b/src/power_grid_model/validation/rules.py
index 721b43b8b..0b197fbc2 100644
--- a/src/power_grid_model/validation/rules.py
+++ b/src/power_grid_model/validation/rules.py
@@ -917,10 +917,11 @@ def all_supported_tap_control_side(  # pylint: disable=too-many-arguments
     invalid = np.zeros_like(mask)
 
     for ref_component, ref_field in tap_side_fields:
-        indices = get_indexer(data[ref_component]["id"], data[component][regulated_object_field], default_value=-1)
-        found = indices != -1
-        ref_comp_values = data[ref_component][ref_field][indices[found]]
-        invalid[found] = np.logical_or(invalid[found], values[found] == ref_comp_values)
+        if ref_component in data:
+            indices = get_indexer(data[ref_component]["id"], data[component][regulated_object_field], default_value=-1)
+            found = indices != -1
+            ref_comp_values = data[ref_component][ref_field][indices[found]]
+            invalid[found] = np.logical_or(invalid[found], values[found] == ref_comp_values)
 
     if invalid.any():
         return [
diff --git a/src/power_grid_model/validation/utils.py b/src/power_grid_model/validation/utils.py
index e8dd226aa..ed2a0347e 100644
--- a/src/power_grid_model/validation/utils.py
+++ b/src/power_grid_model/validation/utils.py
@@ -196,12 +196,16 @@ def get_indexer(source: np.ndarray, target: np.ndarray, default_value: Optional[
     Raises:
         IndexError: if default_value is None and there were values in target that were not in source
     """
+
     permutation_sort = np.argsort(source)  # complexity O(N_input * logN_input)
     indices = np.searchsorted(source, target, sorter=permutation_sort)  # complexity O(N_update * logN_input)
 
     if default_value is None:
         return permutation_sort[indices]
 
+    if len(source) == 0:
+        return np.full_like(target, fill_value=default_value)
+
     clipped_indices = np.take(permutation_sort, indices, mode="clip")
     return np.where(source[clipped_indices] == target, permutation_sort[clipped_indices], default_value)
 
diff --git a/tests/unit/validation/test_rules.py b/tests/unit/validation/test_rules.py
index c21ee785f..6f258826e 100644
--- a/tests/unit/validation/test_rules.py
+++ b/tests/unit/validation/test_rules.py
@@ -27,6 +27,7 @@
     NotUniqueError,
     SameValueError,
     TwoValuesZeroError,
+    UnsupportedTransformerRegulationError,
 )
 from power_grid_model.validation.rules import (
     all_between,
@@ -44,6 +45,7 @@
     all_less_than,
     all_not_two_values_equal,
     all_not_two_values_zero,
+    all_supported_tap_control_side,
     all_unique,
     all_valid_clocks,
     all_valid_enum_values,
@@ -545,3 +547,35 @@ def test_all_valid_fault_phases():
     errors = all_valid_fault_phases(invalid, "fault", "foo", "bar")
     assert len(errors) == 1
     assert FaultPhaseError("fault", fields=["foo", "bar"], ids=list(range(26))) in errors
+
+
+def test_supported_tap_control_side():
+    valid = {
+        "foo": np.array([(0, 4)], dtype=[("id", "i4"), ("foofoo", "i1")]),
+        "bar": np.array([(1, 5)], dtype=[("id", "i4"), ("barbar", "i1")]),
+        "baz": np.array([], dtype=[("id", "i4"), ("bazbaz", "i1")]),
+        "regulator": np.array([(2, 0, 6), (3, 1, 7)], dtype=[("id", "i4"), ("regulated", "i4"), ("control", "i1")]),
+    }
+    errors = all_supported_tap_control_side(
+        valid,
+        "regulator",
+        "control",
+        "regulated",
+        [("foo", "foofoo"), ("bar", "barbar"), ("baz", "bazbaz"), ("bla", "blabla")],
+    )
+    assert not errors
+
+    invalid = {
+        "foo": np.array([(0, 4)], dtype=[("id", "i4"), ("foofoo", "i1")]),
+        "bar": np.array([(1, 5)], dtype=[("id", "i4"), ("barbar", "i1")]),
+        "regulator": np.array([(2, 0, 4), (3, 1, 5)], dtype=[("id", "i4"), ("regulated", "i4"), ("control", "i1")]),
+    }
+    errors = all_supported_tap_control_side(
+        invalid,
+        "regulator",
+        "control",
+        "regulated",
+        [("foo", "foofoo"), ("bar", "barbar"), ("baz", "bazbaz")],
+    )
+    assert len(errors) == 1
+    assert UnsupportedTransformerRegulationError(component="regulator", fields=["control", "regulated"], ids=[2, 3])