The NEC requires that breaker boxes be installed at a maximum height of 6 feet 7 inches off the floor of your home. This measurement pertains to the breaker box's master shut-off handle, rather than the top or bottom of the box itself. Electricians have the freedom to install the box at any height within this range. When building a home, always check if your municipality's building code contains instructions about the breaker box's height.
The chief reason for the breaker box to be installed at this height is because the shut-off handle is accessible for the majority of people. If the box was installed higher, short people would not be able to reach the handle, which could be a safety hazard.
Although it is permissible to cover the breaker box with wood, the cover must be hinged or otherwise able to open. Never close off the breaker box. Not only would closing it be inconvenient when you need to reset a breaker that has tripped, it would also be dangerous because you wouldn't be able to access the box in the event of an electrical short-circuit or fire.
Breaker boxes are typically located in one of a few different areas. Because they are somewhat of an eyesore, they are most common in areas such as garages and basements. In apartments without garages or basements, breaker boxes are often located in a utility closet. The NEC dictates that the box should not be located in bathrooms or above steps.