Speed of electro-magnetic waves in different medias is different. In some it's faster in some it's slower. The term speed of light is related to SPEED OF LIGHT IN VACUUM (But noone knows what vacuum really is). Also there is a few phenomena.. Speed of radio wave near powerfull transmitting antenna is faster the a speed of light. There are some more known phenomenas plus toooooooons we don't know yet.
I hired an Italian guy to do my wires. Now they look like spaghetti!