I always figured the big breakers at the top thing started because of the old style split bus panels. You always put the big guys up top because the bottom set of breakers was only fed from a 2 pole 50 at the top.
Do we have any pictures or other details about these panels anywhere on ECN?
Here in the U.K. it's been common practice for years to start with the largest breaker next to the main and then work down through the ratings, ending with the 5 or 6A lighting breakers at the far end. There's nothing to say it has to be done that way, but it's a very widely adopted convention.
