For the 2011 National Electrical Code (NEC) process, Code-Making Panel 15 received many proposals recommending changes to Article 517. These proposals were intended to coordinate and correlate with changes to the 2010 NFPA 99 document. Unfortunately, the 2010 version of the NFPA 99 document was returned to committee without adoption at the 2009 NFPA annual meeting, so many of the proposals that Panel 15 accepted at the NEC proposal stage were rejected. However, enough important changes were accepted in Article 517, covering healthcare facilities in the 2011 NEC, that careful study of the new text is warranted.
A new definition was added to 517.2 for battery-powered lighting units as “individual unit equipment for backup illumination consisting of a rechargeable battery, a battery-charging means, provisions for one or more lamps mounted on the equipment, or with terminals for remote lamps, or both, and a relaying device arranged to energize the lamps automatically upon failure of the supply to the unit equipment.”
Accompanying this definition, text was added to 517.63(A), requiring one or more battery-powered lighting units be provided for grounded-power systems in anesthetizing locations. These lighting units shall be permitted to be wired to the critical lighting circuit in the area and connected ahead of any local switches. The purpose of the battery-powered lighting units is to ensure continuity of lighting during short-term power outages in operating rooms, anesthetizing areas and similar critical locations.
In 517.16, receptacles with insulated-grounding terminals [commonly called isolated ground or IG receptacles and identified with an orange triangle on the front of the receptacle and as described in 250.146(D)] are no longer permitted to be installed in patient-care areas of healthcare facilities. The purpose of an IG receptacle is to reduce the effects of electrical noise (electromagnetic interference) on electronic equipment.
In the 2008 NEC, an IG receptacle did not comply with 517.13(A) and (B), since it only provided one method of grounding (the insulated equipment-grounding conductor from the IG receptacle to the service or to an applicable derived system).
For both general-care patient bed locations in 517.18(A) and critical-care bed locations in 517.19(A), a sentence has been added, stating, “the branch circuit serving patient bed locations shall not be part of a multiwire branch circuit.” Not permitting the branch circuits to be multiwire branch circuits will ensure that disconnecting the power to one circuit will not affect the operation of any other branch circuits.
Remember, a multiwire branch circuit is defined as follows: “A branch circuit that consists of two or more ungrounded conductors that have a voltage between them, and a grounded conductor that has equal voltage between it and each ungrounded conductor of the circuit and that is connected to the neutral or grounded conductor of the system.”
For both general-care patient bed locations and critical-care patient bed locations, patient bed receptacles are permitted to be single-, duplex- or quadruplex--type receptacles with the total number of receptacles for each general-care or critical-care bed location still unchanged. The major change here is recognizing hospital-grade, quad-type or four-plex receptacles.
A major change has occurred in 517.30(C)(1), covering separation of the critical branch from the emergency system with the addition of two new paragraphs. The first new paragraph states: “Where general care locations are served from two separate transfer switches on the emergency system in accordance with 517.18(A), Exception No. 3, the general care circuits from the two separate systems shall be kept independent of each other. Where critical care locations are served from two separate transfer switches on the emergency system in accordance with 517.19(A), Exception No. 2, the critical care circuits from the two separate systems shall be kept independent of each other.” In other words, where two separate transfer switches provide emergency system power to a general-care or critical patient-care area and there are no normal circuits to the patient-care area, these two separate circuits must be isolated from each other at the source of the power at the transfer switch to the patient bed location.
Finally, a second paragraph has been added to 517.80, dealing with low-voltage circuits in a patient-care area as follows: “Class 2 and Class 3 signaling and communications systems and power-limited fire alarm systems shall not be required to comply with the grounding requirements of 517.13, to comply with the mechanical protection requirements of 517.30(C)(3)(5), or to be enclosed in raceways, unless otherwise specified by Chapter 7 or 8.”
The changes accomplished in Article 517 for the 2011 NEC cycle should help provide a safer installation for general and critical patient-care areas.
ODE is a staff engineering associate at Underwriters Laboratories Inc., based in Peoria, Ariz. He can be reached at 919.949.2576 and email@example.com.