Perhaps I am interpreteing the article incorrectly when it says
the unit equipment shall supply and maintain not less than 60 percent of the initial emergency illumination for a period of at least 1? hours. Your thoughts?
Are they saying 60% of the initials battery powered illumination. I took it to mean 60% of the emergency(Emergency/Critical branch) powered lighting.
The more I think of it I have not seen more than 3 or 4 in any OR's I been in, But then again I am pretty sure all of the hospitials I have worked in was built prior to the NEC adoption of NEC 517.63. This article was not in the 1996. What is your interpretation of the sentence/Article highlighted in red?
NEC 517.63 Grounded Power Systems in Anesthetizing Locations. (Located in Health Care Facilities of 2008 National Electric Code)
(A) Battery-Powered Emergency Lighting Units. One or more battery-powered emergency lighting units shall be provided in accordance with 700.12(E).
NEC -III. Sources of Power
Article 700.12(E) Unit Equipment. Individual unit equipment for emergency illumination shall consist of the following:
(1) A rechargeable battery
(2) A battery charging means
(3) Provisions for one or more lamps mounted on the equipment, or shall be permitted to have terminals for remote lamps, or both
(4) A relaying device arranged to energize the lamps automatically upon failure of the supply to the unit equipment
The batteries shall be of suitable rating and capacity to supply and maintain at not less than 87? percent of the nominal battery voltage for the total lamp load associated with the unit for a period of at least 1? hours, or the unit equipment shall supply and maintain not less than 60 percent of the initial emergency illumination for a period of at least 1? hours. Storage batteries, whether of the acid or alkali type, shall be designed and constructed to meet the requirements of emergency service.
Unit equipment shall be permanently fixed in place (i.e., not portable) and shall have all wiring to each unit installed in accordance with the requirements of any of the wiring methods in Chapter 3. Flexible cord-and-plug connection shall be permitted, provided that the cord does not exceed 900 mm (3 ft) in length. The branch circuit feeding the unit equipment shall be the same branch circuit as that serving the normal lighting in the area and connected ahead of any local switches. The branch circuit that feeds unit equipment shall be clearly identified at the distribution panel. Emergency luminaires (illumination fixtures) that obtain power from a unit equipment and are not part of the unit equipment shall be wired to the unit equipment as required by 700.9 and by one of the wiring methods of Chapter 3.
Exception: In a separate and uninterrupted area supplied by a minimum of three normal lighting circuits, a separate branch circuit for unit equipment shall be permitted if it originates from the same panelboard as that of the normal lighting circuits and is provided with a lock-on feature.
