According to the National Electrical Code (NEC), luminaires, also referred to as lighting fixtures, have some specific rules for clothes closets in homes. For starters, if you have an incandescent light fixture installed, it must be fully enclosed with a glass over. This keeps hot bulbs from coming into direct contact with a flammable material like a blanket or clothing item. It also allows a safeguard for breaking bulbs.
Second, flourescent fixtures are allowed and can be either recessed or surface-mounted, however, they have their minimum clearance requirements as well.
LED luminaires are also allowed in closets and storage areas. These also need to be fully enclosed, but have specific distances from walls and ceilings. These distances range from 6 inches to 12 inches from walls and ceilings.
As a word of caution remember, things that you place or store in your closet can become the catalyst for a fire in your home. Something that you store on the top shelf of your closet can be placed too close to the light bulb, could fall towards and end up touching the bulb, or ever break the bulb. By relacing a fixture that is not up to safety standards today, you'll have the peace of mind that your home is safe. As for cost, light fixtures that sport a glass housing vary in price from a few dollars on up. It is a small price to pay now versus a big price if the fixture causes a fire in your home. Be on the safe side and update your home's closet lighting today!