At the end of each workshop on the National Electrical Code (NEC), I allow time for discussion. At a major healthcare facility in Houston, I fielded questions pertaining to installations of receptacles and other related equipment. Here are those questions and my answers, which are based on the 2011 NEC.
What is a battery-powered lighting unit (B-PLU), and how is it supposed to be connected and used in an anesthetizing location?
A battery-power lighting unit is manufactured for backup power for illumination in anesthetizing locations and can be connected to the critical branch circuit in the area ahead of any local switches.
Will the B-PLU provide backup power for lighting in the anesthetizing area until the normal or generator set comes online?
B-PLUs provide power for lighting during the transitional period that the generator set is coming online, but they have the capacity to power the lighting for 90 minutes. The units provide this time (90 minutes), in case the generator fails to come online for some reason. See Section 517.2 in the 2011 NEC that defines a B-PLU that is used for this type of installation.
Has there been a change in the way the insulated equipment-grounding conductor (IEGC) is installed and used in the patient-care area of a healthcare facility? If so, please explain the new requirements.
Yes, there has been a revision to 517.13(B) in the 2011 NEC that requires the following items to be connected to the IEGC: (1) the grounding terminals of all receptacles, (2) the metal boxes and enclosures containing receptacles, and (3) all noncurrent-carrying conductors of fixed equipment likely to become energized that are subject to personal contact and are operating at more than 100 volts.
Note that the IEGC must be sized per 250.122 and 517.13(B)(2). An insulated equipment-bonding jumper is permitted to be connected directly to the IEGC and then to the metal box as outlined in 517.13(B)(1). Table 250.122 was changed to 250.122 so that all of the section requirements are addressed. For example, if adjustment factors, correction factors or voltage-drop problems caused the ungrounded conductors to be increased, the IEGC must be increased if necessary per 250.122(B).
Can an electrical contractor install a receptacle with an insulated-grounding terminal where a customer wants such an installation? Will the 2011 NEC permit this type of installation? If not, please explain why it has been changed.
No, it can’t be installed. Section 517.16 has been revised, and the fine print note in previous versions has been deleted. The new language prohibits isolated--grounding receptacles and circuits to be installed in patient care locations. The Code-making panel accepted this revised wording because they felt safety for patients was more important than installing a redundant grounding path for reducing electrical noise on grounding circuits. Note that inspections have been made where the insulated-equipment conductor was connected directly to the isolated-grounding receptacle terminals and insulated equipment-grounding conductor, removing the redundant grounding scheme required by the 2011 NEC. So, this revised section puts more emphasis on patient safety than it does on reducing electrical noise.
Will 517.17(B) in the 2011 NEC permit ground-fault protection (GFP) to be installed? Can GFP be installed ahead of the transfer switch at the service equipment or at the generator set? Can it be installed on the load side of the transfer switch, or does GFP have to be installed on the line side of the transfer switch?
First of all, revisions and deletions were incorporated into the GFP requirements pertaining to feeders installed in healthcare facilities and permits GFP be installed on the line side but not on the load side of the transfer equipment. Secondly, GFP can be installed ahead of the transfer equipment at the service equipment and also is permitted to locate at the generator set.
Is it permissible per 517.18(A) to use a multiwire circuit to supply power to receptacles located at the patient bed location in a healthcare facility? If so, can two ungrounded conductors from the same phase having an oversized neutral conductor be considered a multiwire circuit?
First, no. The 2011 NEC will not permit branch circuits to be part of a multiwire circuit system when they serve receptacles located at the bed location in general care and critical-care areas. Second, no. It is 200.4 and not 210.4 that prohibits two ungrounded conductors with an oversize neutral to be considered a multiwire circuit to be used for supplying these branch circuits.
STALLCUP is the CEO of Grayboy Inc., which develops and authors publications for the electrical industry and specializes in classroom training on the National Electrical Code and other standards, including those from OSHA. Contact him at 817.581.2206.