diff --git a/src/units.c b/src/units.c
index 2241d441ec9af9b6d5083191e8f61010ebaccb20..05b83a3427cc40efe8a9cc3a79aa48fec4af05c1 100644
--- a/src/units.c
+++ b/src/units.c
@@ -320,9 +320,15 @@ void units_get_base_unit_exponants_array(float baseUnitsExp[5],
 
     case UNIT_CONV_VOLUME:
       baseUnitsExp[UNIT_LENGTH] = 3.f;
+      break;
 
     case UNIT_CONV_INV_VOLUME:
       baseUnitsExp[UNIT_LENGTH] = -3.f;
+      break;
+
+    default:
+      error("Invalid choice of pre-defined units");
+      break;
   }
 }