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Health Care Power Distribution

Question asked by yasser.amer@dargroup.com on Mar 14, 2018

Reference to NEC Article 517, section 517.30 (B), (2) titled “Transfer switches”: The number of transfer switches to be used shall be based on reliability, design, and load considerations. Each branch of the essential electrical system shall have one or more transfer switches. One transfer switch and downstream distribution system shall be permitted to serve one or more branches in a facility with a maximum demand on the essential electrical system of 150 kVA.

And to NFPA 99, paragraph 6.4.2.2.1.4: “The number of transfer switches to be used shall be based upon reliability, design, and load considerations.

(A) Each branch of the essential electrical system shall have one or more transfer switches.

(B) One transfer switch shall be permitted to serve one or more branches in a facility with a continuous load on the switch of 150 kVA (120 kW) or less.

 

My question: If the life safety and critical branch loads exceed the 150 KVA (for example 600 KVA), shall I divide the load into 4 bunches of 150 KVA?

And if my load is 200 KVA, shall it be divided into two bunches so that no to exceed the 150 KVA limit?

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