Many AOE spells use a point as their origin, and from this point, area is calculated. Faerie Fire doesn't state where spells start. Often, AOE spells are cast in rooms near walls to avoid friendly fire, so part of the spell is negated by the wall, and friendly creatures are safe. Can Faerie Fire be cast this way?
Let's say caster and friendly creatures are in a room measuring 20 by 20 feet. The caster wants to use the Faerie Fire spell. This spell can affect the whole area, including caster and friends. Can caster cast spell partially "inside wall" to avoid affecting friendly creatures?