diff --git a/src/ifcopenshell-python/ifcopenshell/util/system.py b/src/ifcopenshell-python/ifcopenshell/util/system.py
index 3a5be9693f..ac19ab3c35 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/system.py
+++ b/src/ifcopenshell-python/ifcopenshell/util/system.py
@@ -39,6 +39,12 @@ group_types: dict[str, tuple[str, ...]] = {
     "IfcSystem": ("IfcProduct",),
     "IfcGroup": ("IfcObjectDefinition",),
 }
+# Subclasses.
+group_types["IfcDistributionCircuit"] = group_types["IfcDistributionSystem"]
+# Replaced by IfcDistributionCircuit in IFC4, though it wasn't limited to IfcDistributionElements:
+# "Usage of IfcElectricalCircuit is as for the supertype IfcSystem".
+group_types["IfcElectricalCircuit"] = group_types["IfcSystem"]
+
 
 FLOW_DIRECTION = Literal["SINK", "SOURCE", "SOURCEANDSINK", "NOTEDEFINED"]
 
diff --git a/src/ifcopenshell-python/test/util/test_system.py b/src/ifcopenshell-python/test/util/test_system.py
index 2796c3c3d2..892d9e2fdf 100644
--- a/src/ifcopenshell-python/test/util/test_system.py
+++ b/src/ifcopenshell-python/test/util/test_system.py
@@ -21,7 +21,23 @@ import test.bootstrap
 import ifcopenshell.api
 import ifcopenshell.api.root
 import ifcopenshell.api.system
+import ifcopenshell.util.schema
 import ifcopenshell.util.system as subject
+from typing import get_args
+
+
+class TestValidateGroupTypes:
+    def test_run(self):
+        ifcsystem_classes = set()
+        for schema_name in get_args(ifcopenshell.util.schema.IFC_SCHEMA):
+            schema = ifcopenshell.schema_by_name(schema_name)
+            declaration = schema.declaration_by_name("IfcSystem")
+            declarations = ifcopenshell.util.schema.get_subtypes(declaration)
+            ifcsystem_classes.update(d.name() for d in declarations)
+
+        used_classes = set(subject.group_types)
+        unused_classes = ifcsystem_classes - used_classes
+        assert not unused_classes
 
 
 class TestIsAssignable(test.bootstrap.IFC4):