Work surface or countertop?

There are different code requirements for countertops and work surfaces. How do I know which one applies?

The terms counter, countertop and work surface are defined in Article 100. A countertop is a fixed or stationary surface typically used for food or beverage preparation or serving (such as in a kitchen, deli, restaurant or bar), personal lavation (bathroom) or laundering, or a similar surface that faces a routine risk of large quantities of liquids spilling onto outlets mounted directly on or in the surface. A work surface may look the same, but the location clearly intends dry use and tasks other than those in the definition of a countertop. A work surface presents an incidental risk of spilling much smaller quantities of liquids.

Wall or counter receptacles?

During a custom kitchen renovation, a peninsula counter was installed to separate the family room from the kitchen. The peninsula counter height was 36 inches. We installed wall receptacles in the family room under the peninsula counter as always. An inspector forced us to move the receptacles at 18 inches down to below 1 foot where the wall went along the peninsula. Is that right?

The inspector is correct. The general requirements for receptacles in wall spaces are found in 210.52(A), and those for countertops or work surfaces are located in 210.52(C). The space you have identified requires receptacles installed in accordance with 210.52(A)(1), meaning that no point measured horizontally along the floor line of any wall space is more than 6 feet from a receptacle outlet. Section 210.52(A)(2)(3) provides prescriptive requirements for wall spaces and list item (3) addresses spaces with fixed room dividers such as a bar-type counter that includes a peninsular countertop. Also see 210.52(A)(5), which mandates that receptacle outlets installed in these spaces [covered in 210.52(A)(2)(3)] below countertops or work surfaces are prohibited to be within 2 feet of the countertop or work surface.

Bonding metal raceway

When we install grounding electrode conductors (GECs), we typically install them in EMT. Is it acceptable to bond the GEC at just one end?

No. See Section 250.64(E)(1), which requires that ferrous metal raceways for GECs be electrically continuous from the point of attachment to cabinets or equipment to the grounding electrode and must be securely fastened to the ground clamp or fitting. This section mandates ferrous metal raceways be bonded at each end of the raceway to the GEC to create an electrically parallel path.

ESS disconnect marking

Are the disconnects for a data center energy storage system (ESS) required to have an incident energy analysis done with labeling?

An arc flash label applied in accordance with acceptable industry practice is required. See Section 706.15(C), which requires that each ESS disconnect clearly indicate whether it is in the open (off) or closed (on) position. This requirement also mandates permanent marking of the nominal ESS output voltage, the available fault current derived from the ESS, an arc flash label applied in accordance with acceptable industry practice and the date the calculation was performed.

The code user must go to NFPA 70E for an acceptable industry practice. The 70E requirement in Section 130.5(H) requires marking of the nominal system voltage and the arc flash boundary. Additional marking requires one of the following: (1) the available incident energy and corresponding working distance, or the arc flash PPE category, (2) the minimum arc rating of clothing or (3) a site-specific level of PPE. Note that the NEC mandates labeling of the date the calculation was performed, while NFPA 70E does not.

Explanatory material

Why does the NEC contain informational notes and annexes? Shouldn’t there just be requirements only? Seems to add confusion!

Explanatory material in the NEC is necessary. See Section 90.5(C), which explains that references to other standards, related sections within the NEC or information related to an NEC rule is included in the form of informational notes or informative annexes. The NEC technical committees make the determination on when and where additional information is required without adding mandatory text.

A good example is the requirement in Section 695.3, which mandates that the individual source [695.3(A)] chosen to supply a fire pump must be reliable, or multiple sources are required in 695.3(B). In this case, the code user would not know how to determine if the individual source (typically an electric utility service connection) is reliable. The informational note following 695.3 sends the user to the 2019 edition of NFPA 20, Standard for the Installation of Stationary Pumps for Fire Protection, sections 9.3.2 and A.9.3.2, for guidance on determining the power source reliability.

Large equipment

Are two means of egress required where there are multiple disconnects with a combined ampere rating of over 1,200A? We are getting mixed signals from the township’s plan reviewers.

TThe general requirement in Section 110.26(C)(2)(1) requires large equipment (rated 1,200A or more and more than 6 feet wide) containing overcurrent protective devices, switching devices or control devices to have one entrance to and egress from the required working space at each end of the working space. Section 110.26(C)(2)(2) addresses your question. This requirement applies the general rule for two means of entrance to and egress from the working space where the disconnects are installed in accordance with 225.33(A) (for outside feeders) or 230.71(B) (for service disconnecting means) where the combined ampere rating is 1,200A or more and the combined width is over 6 feet.

Section 225.33(A) permits not more than six feeders to supply a separate structure/building, provided the feeders originate in the same panelboard, switchboard or other distribution equipment, and each feeder terminates in a single disconnecting means in the same location. Section 230.71(B) permits two to six service disconnects in accordance with one or more of the five list items provided. Where the combined ampere rating is 1,200A or more and the combined width (of disconnects, circuit breaker enclosures, fused disconnects, panelboards, etc.) is 6 feet or more, the general rule is that two means of entrance to and egress from the working space is required. The permissive requirements in 110.26(C) for conditions including unobstructed egress or extra working space may permit a single entrance and egress.

60°C or 75°C ampacity?

A consultant is telling us that where MC cable is installed in thermal insulation, the maximum ampacity is the 60°C ampacity. We installed 3-conductor MC cable with 2-AWG copper and an equipment ground as seen on approved drawings. This feeder is protected at 125A. The calculated load is less than 70A. Is the consultant correct?

No, see Section 330.80(C) for requirements affecting Type MC cable installed in thermal insulation. This requires derating only where more than two Type MC cables containing two or more current-­carrying conductors in each cable are installed in contact with thermal insulation, without maintaining spacing between the MC cables. In this case, the 75°C ampacity, 115A, can be applied.

Since 115A does not correspond to a standard size amp rating for a fuse or circuit breaker, Section 240.4(B) permits rounding up to the next standard size at 125A. It is likely that the consultant is confused and is applying Section 320.80(A)(1), which applies to Type AC cable. Where installed in thermal insulation, Type AC cable must have conductors rated at 90°C and the final ampacity in these applications cannot exceed the ampacity of a 60°C-rated conductor.

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