For the 2011 edition of the NEC on page 275 of the softbound Code book, they have added the requirement for field identification of all switchboards and panelboards, to indicate where the power to that equipment originates. It will be easier to mark these panel and switch boards when they are installed. Trying to find the source 5 or 10 years down the road has always been a time consuming project that only takes minutes when first installed. A great addition to the code, will make life as an electrician easier in the future. Till next time work safe and be safe.
Jake