In bathrooms with single bowl vanities, it is best to position fixtures on both sides of the mirror to provide light to both sides of your face. These fixtures should be at least 28" apart and centered at 60" above the floor. If a lighting outlet is centered above the mirror, the fixture should be at least 18" wide; however, 24" is much better.
In bathrooms with double bowl vanities, it may be necessary to select two fixtures, positioning one fixture over each sink. Another alternative is to mount a single strip over the mirror. As a general rule, the fixture width should be at least 1/3 of the width of the vanity. Again, this allows the light to illuminate both sides of your face.
In rooms or hallways, sconces or brackets should be mounted so that the upper edge of the fixture is at least 74" from the floor. However, the fixture should be placed high enough that the tallest resident will not be able to see down into the fixture. If the sconce or bracket is going to be used in handicapped- accessible locations, the fixture must comply with the Americans with Disabilities Act (ADA). There are specific mounting criteria for these fixtures. Please check with your local building code authority for more information.
Chandelier Width Guidelines
Chandeliers should be scaled to the size of the table that it will be placed over. A starting point is to take the table's width and subtract 12 inches. Example: If the table is 42" wide, the chandelier should be 30" wide.
Another consideration is room size, especially if the chandelier is not going over a table (in a foyer for example). Determine the size of the chandelier relative to the room's size by measuring the room from corner to corner diagonally across the room. This dimension in feet should equal the fixture diameter in inches. Example: If the room measures 30' diagonally then you should buy a 30" diameter chandelier.
Chandelier Hanging Height
A good guideline is to make sure the fixture hangs at least 32" over the top of the table top (this is based on an 8' ceiling). Add 3 inches for every foot of additional ceiling height. Example: For a 9' ceiling the chandelier should hang 35" over the table.
When hanging a foyer fixture, always ensure that the bottom of the fixture does not extend below 84" above the floor (to ensure door swing and tall people clearance). If the foyer is a two story entry, try to center the hanging fixture in the space so that if windows are present, the fixture will be centered in the window when looking in from the outside