Technical Corner For the article this month we will take a look at routing of wiring that connects to life safety equipment such as an emergency light or exit sign. NEC 700 Emergency Systems deals with systems essential for safety of human life. NEC 701 Legally Required Standby Systems are intended to provide power to aid in firefighting, rescue operations and control of health hazards such as mechanical ventilation systems. NEC 702 Optional Standby Systems are those that upon failure can cause physical discomfort, interruption of an industrial process, damage to process equipment or disruption of business. NEC 700 is by far the most stringent with some extra ordinary requirements that are geared toward ensuring the operation of the emergency equipment in order to protect human life. An example of this is the wiring associated with an emergency light or exit sign. NEC 700.10 (B) basically states that wiring for emergency circuits must be kept independent of all other wiring systems. The idea here is that a fault in the other systems will not affect the performance of the emergency circuits. This is very similar to the concept of separating emergency loads from non-emergency loads by using separate transfer switches. An interesting note, it appears that 700.10 (B) allows 2 or more emergency circuits from the same source in the same raceway, cable, box, or cabinet. A good way to make sure a contractor captures this is to add it to a general note for your project or make sure this is described in the project specs. Code references courtesy of NEC 2017 Code version. Hopefully this article finds you well and can be used as a reference for your project needs. If anyone would like to contribute to the Rochester Engineer and add an article or would like to request information on a specific topic (not limited to Electrical) just email me at beliasz@bergmannpc.com. As always, any comments are appreciated…! Thank you for reading. Brett Eliasz, P.E., LEED AP BD+C , RES Director
8 | The ROCHESTER ENGINEER JUNE 2021
res - technical corner
