1. The place of supply of goods shall be deemed to be:
(a) in the case of goods dispatched or transported either by the supplier or by the person to whom they are supplied or by a third person: the place where the goods are at the time when dispatch or transport to the person to whom they are supplied begins. Where the goods are installed or assembled, with or without a trial run, by or on behalf of the supplier, the place of supply shall be deemed to be the place where the goods are installed or assembled. In cases where the installation or assembly is carried out in a Member State other than that of the supplier, the Member State within the territory of which the installation or assembly is carried out shall take any necessary steps to avoid double taxation in that State;
(b) in the case of goods not dispatched or transported: the place where the goods are when the supply takes place;
(c) in the case of goods supplied on board ships, aircraft or trains during the part of a trans