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Friday, June 16, 2023
Question:
Hello CQD, the 2020
NEC® 700.3(F) requires a permanent switching means to connect a temporary power source for emergency systems. What is the definition of an emergency system? What loads are considered emergency system loads? Does this include Article 701 systems? Is a fire pump an emergency load? If this does include fire pumps, Article 695 does not allow for multiple fire pump disconnects? This is a very grey area in my opinion. The issue is that the facility we are performing maintenance on is always occupied so therefore the emergency system needs to stay operational during maintenance. Thanks for your insight, Lee Newton
A
Answer:
Hello Lee, and thanks for your questions. There is a lot to unpack here so let’s go through them one at a time.
- Section 700.2 of the 2020 NEC® defines Emergency Systems as: Those systems legally required and classified as emergency by municipal, state, federal, or other codes, or by any governmental agency having jurisdiction. These systems are intended to automatically supply illumination, power, or both, to designated areas and equipment in the event of failure of the normal supply or in the event of accident to elements of a system intended to supply, distribute, and control power and illumination essential for safety to human life.
- The loads connected to the emergency system are typically those loads necessary to aid in the speedy evacuation of a building or structure. The 2021 International Building Code (IBC) Chapter 27 provides guidance on what loads are required to be supplied by the emergency system. Specifically, Section 2702.2 provides guidance on which electrical loads get connected to the emergency system and which loads get connected to the legally required standby system.
- The requirement found in Section 700.3(F) for permanent provisions for the connection of a temporary power source does not extend to legally required standby systems as covered by Article 701.
- In certain buildings fire pumps are required to be connected to the emergency system. Section 695.4(B)(c) permits an additional disconnect for fire pumps supplied by an on-site generator.