The European General Court provides clarification in a case concerning the use of Hypertherm electrodes in welding torches. The following aspects are of importance. The component has to be a consumable that must be replaced frequently and it can be replaced quickly and easily by the end user without taking the whole device apart. If this is the case, it seems more like a separate design than a component of a composite model.
If the item and the part are both for sale separately (if it is missing, the buyer will not immediately think the device is broken). Also important: if the part is interchangeable with other products/electrodes, this interchangeability is also a good indication that it is not a part of a composite product, but its own product for which design protection can be claimed.
