Selective coordination in low-voltage power distribution systems: Is the level important?

The requirements for selective coordination were expanded in the 2005 NEC. These mandatory requirements have removed the flexibility engineers previously had to balance coordination with other important system design criteria. What level of selective coordination really provides value and what level is unjustified because of other compromises? The various aspects of this question are discussed for the purpose of stimulating thoughtful discussion prior to the start of the 2011 NEC code revision cycle. Relevant literature is reviewed and a ldquoreal worldrdquo example is cited to illustrate the problem.