NEC 725.136

NEC 700.10(B)(1)

NEC 700.10(B)(1) requires emergency circuit wiring to be kept entirely independent of all other wiring and equipment. Routing emergency and normal power in the same raceway means a single fire or physical damage event can disable both systems simultaneously, eliminating the redundancy that emergency power provides.

NEC 700.32 / 701.27

NEC requires selective coordination of overcurrent protective devices for emergency systems, legally required standby systems, and critical operations power systems. Without it, a fault on one circuit can trip upstream devices, blacking out the entire system.

NEC 708.22

This fails code. NEC Article 708 (Critical Operations Power Systems) Section 708.22 (Capacity of Power Sources) requires the alternate power source to be sized for a minimum of 72 hours (3 days) of full-load operation of the Designated Critical Operations Area. The 24-hour supply provides only about 33% of the required minimum run time. The 72-hour requirement exists because during major disasters such as hurricanes, earthquakes, or ice storms, fuel delivery infrastructure can be disrupted for days or even weeks. A COPS facility must be capable of sustaining critical operations independently during extended emergencies, regardless of assumptions about local fuel delivery availability. Management convenience or cost considerations do not override this code requirement.

NEC 760.49 / IBC 909.11

NEC 760.49 and IBC 909.11 require fire alarm circuits serving smoke control functions to use fire-rated wiring (2-hour rated CI cable or wiring in 2-hour rated enclosures). Standard fire alarm cable that burns through in the first minutes of a fire will disable smoke damper control precisely when it is needed most.

NEC Article 725.136(A)

Low-voltage sensor wiring (Class 2) must be run in separate conduit from line-voltage power wiring per NEC Article 725.136(A). Electromagnetic interference from the 120V power induces noise on the sensor signal, causing erratic readings and unstable control loops on the new DDC system.

NEC Chapter 9 Table 1 & Annex C Table C.1 / Article 358.22

1/2" EMT has only 0.122 sq in of usable area at 40% fill (Chapter 9, Table 4). Each #12 THHN is 0.0133 sq in (Chapter 9, Table 5), so ten conductors require 0.133 sq in — over the 40% limit. NEC Annex C, Table C.1 permits a maximum of 9 #12 THHN in 1/2" EMT.