I was merrily tabbing my new NEC 2008 when - wow - new article! With some unexpected surprises. From what I gather, article 708 "Critical Operations Power Systems (COPS)" was based in large part on Army Corps of Engineer tech manuals which I've already been using for years, and most of the article is common sense stuff finally put to paper, but there were a few points that I'm not quite clear on. Or maybe I am perfectly clear on, but just don't want to believe it. What's your all take on this?
709.10(C) appears to essentially prohibit EMT, cable trays and cable trenches from pretty much anything connecting to a generator or UPS upstream of the final power distribution unit/branch panel. Are cables allowed to be exposed when transitioning between duct banks in manholes?
708.10(C) requires 1-hour fire resistance on all feeders... is THHN in IMC 1-hour fire resistant?
708.14(1) requires all signal and communications wire to be shielded twisted pair. Does this apply to thermostat bell wire? And #14 alarm cabling? I don't believe I've seen shielded twisted pair in gauges that large. I can see the IT guys going nuts over this one, too, though honestly, there's no reason NOT to be using shielded Cat5 for critical applications.
708.14(8) further requires HVAC cables (including shielded bell wire?) to have a 2-hour fire rating.
708.22(A) appears to require prime-rated generators, even in standby applications.
708.52(B) appears to require individual ground fault protection on all circuits of a ground-fault protected wye switchboard. Coordinated, too, I'd hope, though coordination isn't explicitely mentioned. Makes sense, but I don't think I've seen this on any LV switchgear.
Last edited by SteveFehr; 01/29/08 08:04 AM.
