I wouldn't spray it on any kind of electronics, the cord itself would be fine, providing its in good condition, just be aware some dogs don't mind bitter apple. Keeping your pup away from these things would be your best bet. If you are unable to watch him/her, kennel up or crate.
However, my mom's Frenchie's LOVED the taste of bitter apple spray! D:
My lab was the same way. I would recommend testing it on something less valuable before you spray it on anything you actually want to protect, just in case. I sprayed on a piece of wood (my sliding glass door jammer) and that was the next thing that she wanted to eat.