diff --git a/_unittest/test_28_Maxwell3D.py b/_unittest/test_28_Maxwell3D.py
index 9cb02156b5e..fb1a7b4ede0 100644
--- a/_unittest/test_28_Maxwell3D.py
+++ b/_unittest/test_28_Maxwell3D.py
@@ -483,12 +483,16 @@ def test_32_matrix(self, add_app):
         rectangle2 = m3d.modeler.create_rectangle(0, [9, 1.5, 0], [2.5, 5], name="Sheet2")
         rectangle3 = m3d.modeler.create_rectangle(0, [16.5, 1.5, 0], [2.5, 5], name="Sheet3")
         rectangle4 = m3d.modeler.create_rectangle(0, [32.5, 1.5, 0], [2.5, 5], name="Sheet4")
+        box1 = m3d.modeler.create_box([0, 0, 0], [10, 10, 5], "MyBox1")
+        box2 = m3d.modeler.create_box([10, 10, 10], [10, 10, 5], "MyBox2")
 
         m3d.assign_voltage(rectangle1.faces[0], amplitude=1, name="Voltage1")
         m3d.assign_voltage("Sheet1", amplitude=1, name="Voltage5")
         m3d.assign_voltage(rectangle2.faces[0], amplitude=1, name="Voltage2")
         m3d.assign_voltage(rectangle3.faces[0], amplitude=1, name="Voltage3")
         m3d.assign_voltage(rectangle4.faces[0], amplitude=1, name="Voltage4")
+        m3d.assign_voltage(box1.faces, amplitude=1, name="Voltage6")
+        m3d.assign_voltage(box2, amplitude=1, name="Voltage7")
 
         L = m3d.assign_matrix(assignment="Voltage1")
         assert L.props["MatrixEntry"]["MatrixEntry"][0]["Source"] == "Voltage1"
diff --git a/pyaedt/maxwell.py b/pyaedt/maxwell.py
index 99a61115fe3..bb1b321f486 100644
--- a/pyaedt/maxwell.py
+++ b/pyaedt/maxwell.py
@@ -1007,7 +1007,13 @@ def assign_voltage(self, assignment, amplitude=1, name=None):
                 else:
                     props = OrderedDict({"Faces": assignment, "Value": amplitude})
             else:
-                props = OrderedDict({"Faces": assignment, "Voltage": amplitude})
+                object_names_set = set(self.modeler.object_names)
+                props = OrderedDict({"Faces": [], "Objects": [], "Voltage": amplitude})
+                for element in assignment:
+                    if isinstance(element, str) and element in object_names_set:
+                        props["Objects"].append(element)
+                    else:
+                        props["Faces"].append(element)
         bound = BoundaryObject(self, name, props, "Voltage")
         if bound.create():
             self._boundaries[bound.name] = bound