Mike Dolt Enterprises
Mike Dolt Enterprises
User: ncwirenut, Location: Fl
Asked on: Friday, April 1, 2011 at 12:54 pm EDT
Answered on: Tuesday, May 14, 2024 at 3:37 am EDT
Question: Plan review has turned us down because we have set a panel beside of the generator to distribute the generator power at a nursing home. They say we cannot share the Life Safety and the Critical Care power after it leaves the generator. This is a new building with one Life Safety ATS and three Critical Care ATS. Their recomendation is to set a trough inside of the generator and tap these panels in the trough. I'm probably wrong but I never thought that the seperation applied before the transfer switch. Any thoughts?
NFPA 70: National Electrical Code (NEC)
Section 700.12(B) of the NEC states that "Life safety branch circuits shall not be connected to the same emergency source as other circuits except where required for the operation of emergency systems and equipment as permitted in 700.16(B) through (G)."NFPA 99: Health Care Facilities Code
Section 4.3.
3.4.3 of NFPA 99 states that "Life safety branch circuits shall not be connected to the same emergency source as other circuits, except where required for the operation of emergency systems and equipment as permitted by 4.
3.3.4.4 through 4.
3.3.4.
7."Interpretation
Based on the above code requirements, the plan review authority's interpretation that the Life Safety and Critical Care power cannot be shared outside the generator is correct.
Separation of Power Sources
The purpose of separating Life Safety and Critical Care power sources is to ensure that critical loads, such as fire alarms, emergency lighting, and medical equipment, are not disrupted in the event of a failure of one power source. By sharing power after the generator, this separation is compromised, as a fault in the shared distribution panel could affect both Life Safety and Critical Care circuits.
Trough Inside the Generator
The recommendation to install a trough inside the generator to tap panels is a common practice that complies with the code requirements. By installing the panels within the generator enclosure, the separation of power sources is maintained, as the Life Safety and Critical Care panels are not connected to the same emergency source outside the generator.
Exemptions
The NEC and NFPA 99 allow for certain exceptions to the separation rule, such as: Connecting Life Safety circuits to the same emergency source as Critical Care circuits for operation of emergency systems and equipment. Connecting Life Safety circuits to a single emergency source that also supplies other branch circuits, provided that the Life Safety circuits are isolated by automatic transfer switches.However, these exceptions do not apply in this case, as the plan reviewer has specifically disallowed sharing of power after the generator.
Conclusion
Based on the applicable code requirements and the plan reviewer's interpretation, it is not permissible to set a panel beside the generator to distribute power to both Life Safety and Critical Care circuits. The recommended solution of installing a trough inside the generator to tap panels is an acceptable practice that complies with the code requirements. Flag for review