I have a question about the current rating of bus bars and switches. I have a 12V system, and the bus bar I was planning on using has a rating of 250A. However, it says that this rating is for a 48V system. Does this mean that it has a rating of 1000A for a 12V system? Or does it not work like that - is it only the current value that matters? An explanation of the physics behind this would be greatly appreciated! Thanks