Jim Dollard has an extensive background in codes and standards. If you have a query about the National Electrical Code (NEC), Jim will help you solve it. Send questions to firstname.lastname@example.org. Answers are based on the 2017 NEC.
Patient bed locations
How does the definition of receptacle affect the number of contact devices for patient bed locations? Who determines the minimum number of things that can be plugged in at one bed location?
Section 517.18(B) requires patient bed locations in Category 2 spaces (old general care areas) to be provided with a minimum of eight receptacles. Patient bed locations in Category 1 spaces (old critical care areas) are required in Section 517.19(B) to be provided with a minimum of 14 receptacles. Each requirement prescriptively states the required receptacles may be of the single, duplex or quadruplex receptacle types or any combination of these three. The required number of receptacles is clear.
In a Category 2 space, there could be eight single receptacles with eight contact devices, eight duplex receptacles with 16 contact devices or eight quadruplex receptacles with 32 contact devices. The designing engineer or the governing body will determine the number of contact devices on each receptacle. A new definition in 517.2 explains the “governing body” is a person (or people) who has the overall legal responsibility for the operation of a healthcare facility.
The Article 100 definition of “receptacle” does not address the terms “duplex” or “quadruplex.” These are considered as a “multiple receptacle.” It is important to note that these NEC requirements are minimum requirements. The designing engineer and governing body will make the determination. Additional requirements and information can be found in NFPA 99, Healthcare Facilities Code.
A change was made in the 2017 NEC to require the testing of ground-fault protection at services with a test method called primary current injection. Why was this added? Why is secondary injection testing not permitted?
The requirement you are referring to is located in Section 230.95(C), which addresses performance testing of the required ground-fault protection of equipment (GFPE) in 230.95. There were multiple changes in this requirement. The first revision requires a qualified person to conduct performance testing of the GFPE.
The public input that drove this revision requested the performance testing to be done by a “qualified testing agency.” The rationale for this suggested revision was to ensure people performing these tests are properly trained, properly equipped and certified to perform the test. The requirement in 230.95(C) is for “the ground-fault protection system” to be “performance tested” when first installed on-site. This requires the test method applied to test all of the GFPE components. Only “primary current injection” tests the entire ground-fault protection system. While there may be a push-to-test button, it only initiates a test-current within the relay or trip unit, not the entire GFPE system. The use of secondary-injection test methods will test the electronics of the relay or trip unit but does not ensure the current installation and wiring are correct.
Requiring performance testing to use a “test process of primary current injection” does not necessarily mandate a specific test. It clarifies the need for an overall procedure that ensures the entire ground-fault protection system is operating satisfactorily.
In Article 100, “receptacle” is defined as a contact device installed at the outlet for the connection of an attachment plug or for the direct connection of electrical utilization equipment designed to mate with the corresponding contact device.
Receptacle, single or multiple?
Perhaps you can weigh in on an issue we have been kicking around on the job. If we install a 20-ampere (A) branch circuit that supplies only one duplex receptacle, is that branch circuit considered a “general-purpose branch circuit,” or is it an “individual branch circuit”?
To answer your question, we must review multiple definitions. In Article 100, “receptacle” is defined as a contact device installed at the outlet for the connection of an attachment plug or for the direct connection of electrical utilization equipment designed to mate with the corresponding contact device. The definition goes further to provide two prescriptive descriptions for different types of receptacles. A “single receptacle” is a single contact device with no other contact device on the same yoke. A “multiple receptacle” is two or more contact devices on the same yoke.
The problem here is we have two definitions that are buried inside the definition of the term “receptacle.” Throughout the NEC, there are prescriptive requirements that specifically identify a “receptacle,” a “single receptacle” or a “multiple receptacle.” The use of each of these terms is very different. For example, 210.21(B)(1) requires that a “single receptacle” on an “individual branch circuit” be protected at an ampere rating not less than that of the branch circuit. As defined in Article 100, an “individual branch circuit” can supply only one utilization equipment.
Taking this a step further, if we remove the “single receptacle” from the previous example and replace it with a duplex receptacle—which is a “multiple” receptacle—the duplex receptacle would not be required to have an ampere rating not less than that of the branch circuit. Furthermore, it would not be an “individual branch circuit” because it could serve more than one utilization equipment. By definition, a “general-purpose branch circuit” supplies two or more receptacles or outlets for lighting and appliances. The definition does not specify “single receptacle” or “multiple receptacle.” Where a branch circuit supplies only one duplex receptacle, it is not a general-purpose branch circuit because it supplies only one receptacle.
Interestingly, by definition, it is not an individual branch circuit either, because it can supply more than one utilization equipment. The complete answer to your question is that we need some work in this NEC revision cycle for clarification.
Disconnect within sight?
The Code does not always require a disconnect to be installed immediately inside the building for a permanently installed 20-kilowatt (kW) generator supplying an optional standby system. We have installed many systems and the disconnect at the generator is the required disconnect. The generator housing is 30 feet from the building it supplies. An engineer is telling us that the generator disconnect is not in sight from the building because it is inside an enclosure. Adding an outdoor disconnect, in my opinion, will not increase safety or enhance the installation. Is the disconnect required?
Section 702.12(A) contains the permissive requirement you address. An additional disconnect (as required by 225.32) is not required where ungrounded conductors from the standby generator serve the building, provided that: the outdoor housed generator set is greater than 15 kW in size, is equipped with a readily accessible disconnecting means accordance with 445.18, and the disconnecting means is located within sight of the building or structure supplied.
The issue here is the application of the defined terms “within sight” and “readily accessible.” In order to be considered within sight, equipment must be visible and not more than 50 feet away. The fact that the disconnecting means is inside an enclosure door does not mean that the disconnect is not within sight. As long as the enclosure containing the disconnecting means is readily accessible, is visible from the building, and is within 50 feet from the building, the requirements of 702.12(A) are met and an additional disconnect is not required.
Extension cord requirements
Does the Code permit replacement cord caps on extension cords? During a recent safety walk-through, we were told that we could not replace a male cord cap on an extension cord. We were also told that we needed to completely roll out the extension cord. We had a 50-foot cord that was only partially unrolled. Is that a requirement?
The NEC does not specifically address replacing an attachment plug on an extension cord. However, Section 240.5(B)(4) specifically addresses overcurrent protection of “field assembled extension cord sets” made with separately listed and installed components.
Requirements for cord types typically used for extension cords are located in Article 400 and Table 400.4. General requirements for attachment plugs and cord connectors are in Section 406.7.
There is no specific reference in the NEC on the replacement of an attachment plug or cord connector on an extension cord. There are multiple OSHA letters of interpretation that address this issue. OSHA permits the replacement of an attachment plug or cord cap, provided the extension cord is returned to its “approved” state. “Approved,” as used in OSHA standards for extension cords, essentially means “listed.”
There may be issues with a molded cord cap that is replaced based on the type of replacement used. However, it is a common practice to replace an attachment plug that may be missing an equipment grounding conductor prong with a listed hard or extra-hard-use cord cap. This is based on a memorandum from OSHA that provides prescriptive requirements for job made cords.
With respect to completely unrolling an extension cord, see the UL product listing for cord sets and power-supply cords ELBZ. The listing information notes that when used in a coiled form, excessive heating may occur. Therefore, when placed into service, all wrappings should be removed, and the flexible cord should be extended for its entire length.