The Annexes of the NEC are often overlooked, yet can make a huge difference in the cost and delivery of projects that involve expansion, renovation, or upgrades. Reviewing your bill of materials against Annex A can prevent the cost of ripping out installed equipment and materials, then replacing with other equipment and materials your insurer will accept.

For example, suppose your company has decided to bring database work in-house for security reasons. So, you're going to have a UPS and some high-end work stations. The electrical equipment isn't an issue, because the distributor you deal with carries only listed components. But what about those office furnishings?

You can look that up in Annex A and then specify they must conform to UL1286. That UPS, by the way, should conform to UL 1778. The surge protectors you're going to install should conform to IEEE C62. If you were doing a project that involved combustibles, you'd look in Annex A for the relevant ISA standards.

Annex E is another NEC resource that applies to the expansion and renovation projects with which you might become involved. If you're doing those kinds of projects, it really is essential reading, because it helps make sense of the fire-resistance ratings by putting them in the framework of five types of construction.

Will a new project have power systems for critical operations (operations vital to public safety)? If so, turn to Annex F.

Power generation stations have long had supervisory control and data acquisition (SCADA) systems. With onsite power generation becoming increasingly common, SCADA is finding its way into MRO settings. Consult Annex G.