diff --git a/sources/conductorpropertieswidget.cpp b/sources/conductorpropertieswidget.cpp
index 6fe1ba5b9..94a6f9f8d 100644
--- a/sources/conductorpropertieswidget.cpp
+++ b/sources/conductorpropertieswidget.cpp
@@ -227,7 +227,7 @@ void ConductorPropertiesWidget::updateDisplay() {
 	ground_checkbox -> setChecked(properties_.singleLineProperties.hasGround);
 	neutral_checkbox -> setChecked(properties_.singleLineProperties.hasNeutral);
 	merge_checkbox -> setChecked(properties_.singleLineProperties.is_pen);
-	merge_checkbox -> setEnabled(!isReadOnly() && ground_checkbox -> isChecked() && neutral_checkbox -> isChecked());
+	merge_checkbox -> setEnabled(!isReadOnly() && properties_.type == ConductorProperties::Single && ground_checkbox -> isChecked() && neutral_checkbox -> isChecked());
 	phase_spinbox -> setValue(properties_.singleLineProperties.phasesCount());
 	phase_slider -> setValue(properties_.singleLineProperties.phasesCount());
 	phase_checkbox -> setChecked(properties_.singleLineProperties.phasesCount());