be used shall be based on reliability, design, and load considerations. Each branch of the essential electrical system shall be served by one or more transfer switches. One transfer switch shall be permitted to serve one or more branches or systems in a facility with a maximum demand on the essential electrical system of 150 kVA. [99:4.5.2.2.1]

FPN No. 1: See NFPA 99-2005, Standard for Health Care Facilities, 4.5.3.2, Transfer Switch Operation Type II; 4.4.2.1.4, Automatic Transfer Switch Features; and 4.4.2.1.6, Nonautomatic Transfer Device Features.
FPN No. 2: See FPN Figure 517.41, No. 1. FPN No. 3: See FPN Figure 517.41, No. 2.

Alternate power

equipment is provided that shall be effective for at

least Vh hours and is otherwise in accordance with

700.12 and that shall be capable of supplying lighting

for exit lights, exit corridors, stairways, nursing

stations, medical preparation areas, boiler rooms, and

communications areas. This system shall also supply

power to operate all alarm systems. [99:17.3.4.2.2(3),

18.3.4.2.2(3)]

FPN: See NFPA /0/-2OO6, Life Safety Code.

Normal . system

Normal power source

ri

Nonessential loads

Automatic switching

source

\°

(B) Inpatient Hospital Care Facilities. For those nursing homes and limited care facilities that admit patients who need to be sustained by electrical life support equipment, the essential electrical system from

T equipmen

t

Delayed automatic switching equipment

Critical branch

Life safety branch

the source to the portion of the facility where such

Essential electrical system

FPN Figure 517.41, No. 1 Nursing Home and Limited Health Care Facilities — Minimum Requirement for Transfer Switch Arrangement.

than those listed in 517.42(A) through (G) shall be connected to the life safety branch. The life safety branch shall supply power for the following lighting, receptacles, and equipment.

A

Normal system

\°'

Normal power

source

Nonessential L_

loads

Automatic switching equipmen

t

Critical branch

M

Life safety branch

lternate power source

FPN: The life safety branch is called the emergency system in NFPA 99-2005, Standard for Health Care Facilities.

(A) Ulumination of Means of Egress. Illumination of means of egress as is necessary for corridors, passageways, stairways, landings, and exit doors and all ways of approach to exits. Switching arrangement to transfer patient corridor lighting from general illumination circuits shall be permitted, providing only one of two circuits can be selected and both circuits cannot be extinguished at the same time.

FPN: See NFPA 707-2006, Life Safety Code, Sections 7.8 and 7.9.
(B)Exit Signs. Exit signs and exit directional signs.
FPN: See NFPA 707-2006, Life Safety Code, Section 7.10.

Essential electrical system

FPN Figure 517.41, No. 2 Nursing Home and Limited Health Care Facilities — Minimum Requirement (150 kVA or less) for Transfer Switch Arrangement.

(C) Capacity of System. The essential electrical system shall have adequate capacity to meet the demand for the operation of all functions and equipment to be served by each branch at one time.

(D) Separation from Other Circuits. The life safety branch shall be kept entirely independent of all other wiring and equipment and shall not enter the same raceways, boxes, or cabinets with other wiring except as follows: