When Penny was a pup we spent most of the time in the dining room and kitchen, with all books, cables etc either barriacaded off or out of reach ( I wasn't too bothered about the furniture as we have ... erm ... a shabby chic approach to that

). However, the one absolute no no was the cable from the freezer to the socket, which I couldn't cover 'cos of a door that swung open near it. I tacked it too the wall and rubbed neat washing up liquid on it and (touch wood) she never went near it. I'm not saying it's the best way to deal with it, but it did work.
I have read about a bitter apple spray, but don't know if it's any good.