The main electrical disconnect must be located within 8 feet of entering the building from the service meter. Most of the time you will see the main electrical panel located directly opposite the service meter to satisfy that rule. If a different location is desired, the main disconnect will often be located on the service meter itself, with a sub panel located anywhere in the house. That allows the wire from the new main disconnect to be protected from shorting out. Without that, the wire from the meter to the disconnect is not protected and susceptible to shorting out. Recently on a newer construction in the Waukesha area, the only panel in the house was located in the first floor laundry room.
This is unusual but it was properly wired as a sub panel with a raceway present from the meter to the sub panel. The distance from the meter however, through the basement and to the eventual sub-panel was more than 13 feet, longer than the maximum allowable 8 feet. Because this was newer construction, the Waukesha building inspector was consulted and agreed that the current setup was not right. A separate disconnect needed to be added within 8 feet.