Some people may not consider Article 90 of NFPA 70®, National Electrical Code® (NEC®), to be a backbone of electrical inspector knowledge. But a familiarity with Article 90 is crucial for electrical inspectors. The sections found within Article 90 provide a comprehensive overview of when the NEC applies and when it doesn’t, how the code is arranged, and how enforcement works—all information that is valuable to any electrical inspector. In this blog, we’ll go over some of the information in Article 90 that is important for electrical inspectors to know. What does the NEC cover? Section 90.2(C) lists areas covered by the NEC, and they are: 1.     Public and private premises, including buildings, structures, mobile homes, recreational vehicles, and floating buildings 2.     Yards, lots, parking lots, carnivals, and industrial substations 3.     Installation of conductors and equipment connecting to the supply of electricity 4.     Installations used by electric utility, such as office buildings, warehouses, garages, machine shops, and recreational buildings, that are not an integral part of a generating plant, substation, or control center 5.     Installations supplying shore power to ships and watercraft in marinas and boatyards, including monitoring of leakage current 6.     Installations used to export power from vehicles to premises wiring or for bidirectional current flow As you can see, the NEC addresses installations and methods of accomplishing those installations in its areas of coverage. The fifth item was added in the 2020 edition of the NEC to address installations of shore power and associated receptacles in marinas and boatyards, which may help lower the risk of exposure to electric shock drowning (ESD) through specific changes made in Article 555. The sixth item was also added in the 2020 NEC to deal with new technology around electric vehicles (EVs) and their ability to provide power to premises electrical systems through the EV charging equipment. The changes are reflected in Article 625. What doesn’t the NEC cover? Just as important as knowing what the NEC covers is knowing what it doesn’t. Section 90.2(D) lists the areas that are not under the purview of the NEC, which helps electrical inspectors navigate the out-of-bounds line. This is not to say there are no electrical inspections happening in those areas—just that if there are any, they are likely done using a code or standard other than the NEC for determining compliance. For example, utility-owned service or transmission line installations are covered by the National Electrical Safety Code (NESC) and not the NEC. How is the NEC arranged? The NEC arrangement is outlined in Section 90.3. The NEC is organized so that the requirements found in Chapters 1 through 4 apply generally to all electrical installations referenced in the code, except those referenced in Chapter 8, where the code language must have specific references to the first four chapters. This arrangement helps consolidate general requirements into a few chapters so that they’re not repeated elsewhere in the NEC, which makes it easier for electrical inspectors and installers to locate. Enforcement Information for electrical inspectors around enforcement, interpretations, specific requirements, and what to do with new products, constructions, or materials is found in Section 90.4. According to 90.4(A), the NEC is suitable for mandatory application by governmental bodies that have legal jurisdiction of electrical installations. These bodies are usually state, county, or city governments that incorporate the NEC by reference into their rules or laws. In most instances, electrical inspectors must be working under the authority of an enforcing agency or for an authority having jurisdiction (AHJ) to have any enforcement powers over permitted electrical installations within those jurisdictional boundaries. AHJs have the responsibility for making interpretations of the rules and for deciding on the approval or rejection of equipment or materials used in electrical installations. They may also grant special permission in certain circumstances as they deem necessary. There are two types of rules in the NEC: mandatory and permissive. They are expressed very differently. Mandatory rules are the shall or shall not rules. For example, a mandatory rule would be “the electrical connection of conductors to terminal parts shall ensure a mechanically secure connection without damaging the conductors,” whereas a permissive rule would be “reconditioned equipment shall be permitted except where prohibited elsewhere in the NEC.” As a former AHJ, I frequently would tell electrical inspectors that the code isn’t what you THINK it says; it is what it SAYS it is, so go read the code section before writing a violation or approving an installation. Understanding the difference between mandatory and permissive rules can help the enforcer-installer relationship by having a more accurate inspection. Where to go for more information Electrical inspectors, you are not alone in what you do. NFPA® has an Electrical Inspection Section membership just for you, where you can network with other electrical inspector members. Inspectors can share ideas, talk code, and collaborate on interpretations of the code through NFPA XchangeTM. Having these tools will help create a more consistent enforcement of the NEC.

This is the last in a three-part series on electrical rooms. Read Part 1 here and Part 2 here. Working space about electrical equipment is covered in Article 110 of the NEC.  Up to this point, we have discussed electrical rooms and how the National Electrical Code® (NEC®)—specifically, 110.26—helps ensure there is enough space, especially working space, in those rooms or areas. In Part 2, we observed that changing the voltage alters some of the clearance requirements for the equipment in electrical rooms (see 110.32 and 110.34 of the NEC). Now, we will look at an electrical enclosure, vault, or tunnel that is being used as a method for guarding electrical equipment and see how it affects clearances for working space about electrical equipment. What is an electrical enclosure?  First, let’s look in Article 100 to see if there is a definition for a vault or tunnel. We find there isn’t one, but we do find a definition for enclosure. Enclosure is defined as “the case, housing of an apparatus, or the fence or walls surrounding an installation to prevent personnel from accidentally contacting energized parts, or to protect the equipment from physical damage.” So, does this definition cover an electrical room or vault? I think it could, because the vaults are areas typically surrounded by walls and frequently some form of lockable entrance. Does a vault or enclosure still require working space for electrical equipment? Yes, Parts II and III of Article 110 cover these requirements. For voltages of 50 to 1000 volts, nominal, 110.27(A)(1) would address the use of a room, vault, or similar enclosure that is accessible only to qualified persons, as a means of protection against accidental contact with live parts. For the over 1000 volts, nominal, installations, 110.31(A)—which deals with electrical vaults, including their construction requirements—would apply. Often, we see vaults being utilized as electrical rooms for installations over 1000 volts versus the under-1000-volt installations. This is in part due to electrical installations using exposed terminations or the use of larger substations and switches, which could increase the risk of accidental contact with live parts, depending on the type of equipment. Construction of enclosures  Construction of the vault roof and walls must not be made from studs or wall board, but instead from construction materials that will provide adequate structural strength for the conditions and possess at minimum a 3-hour fire rating. This is usually accomplished using materials that are made from or contain concrete, like a masonry block wall with pre-cast concrete planks for the roof and floor, or a complete pre-cast concrete unit. Where the floor is in contact with earth it must not be less than 4-inch-thick concrete. However, where vacant space or stories are below the floor, it may need to be engineered to be able to structurally withstand the loads imposed on the floor. A vault will normally have access doors as well, which are required to be tight-fitting and have a 3-hour fire rating, unless the vault has an approved fire suppression system installed, in which case the doors can be 1-hour fire rated. These doors must also be lockable, to restrict access to unqualified persons. To allow safe egress in the event of an electrical injury, the doors must be equipped with panic hardware and open 90 degrees in the direction of egress. Don’t forget the signage that must be on the doors (See Part 2 in this blog series for more on signage). Should an electrical catastrophic failure occur, the vault’s robust construction will help mitigate damage to other portions of the building, which could ultimately save lives. This type of heavy-duty construction requires detailed planning from the electrical contractor and design professional for all electrical equipment locations and the penetrations into the vault from feeders, branch circuits, or raceways that will be connecting to that electrical equipment. These penetrations must not reduce the rating of the vault. The electrical equipment contained in the vault, such as the switchgear, transformers/substations, and motor control centers (MCC), must meet the working space requirements found in 110.26, 110.32, and 110.34 of the NEC. The applicable NEC section is determined by the highest nominal voltage for the equipment in a particular area, since there may be more than one voltage within a vault. Where high-voltage equipment is contained within the same vault as equipment 1000 volts or less, there may need to be some separation in accordance with 110.34(B). If the separation is accomplished with a fence controlled by locks, then 110.31 would apply. Table 110.31 contains distance values for the required space between the equipment and the separating fence. Note that the fence cannot be within the working space measurements found in Table 110.34(A). Adding electrical equipment in a vault does not reduce the working space requirements found in 110.26 or 110.34. It just adds some additional items to work around. Whether your electrical equipment is in an electrical room or a vault, you must maintain proper clearances for worker safety. A great way to learn more about working space about electrical equipment is to register for the NFPA online training series on the 2023 edition of the NEC. Working space about electrical equipment is covered in the General Equipment Installation Practices section of this training. Learn more about this comprehensive, self-paced training.  

This is the second in a series of blogs on electrical rooms. Read Part 1 here. In my previous blog, we discussed the misconception that electrical rooms are covered in 110.26 of NFPA 70®, National Electrical Code® (NEC®), when they are actually covered as an option for guarding against accidental contact with live parts in 110.27. Now, we will explore the electrical room and working space for equipment over 1,000 volts, nominal. Does 110.26 still apply to that working space within the electrical room? The answer would be no, because 110.26 is in Part II of Article 110, which covers installations under 1,000 volts, nominal. The applicable part of 110 is Part III: Over 1,000 Volts, Nominal. Specifically, 110.32, Work Space about Equipment; 110.33, Entrance to Enclosures and Access to Working Space; and 110.34, Work Space and Guarding. Coincidently, these sections have some similarities to 110.26, such as requiring: ·       Height for working space of 6.5 feet, measured from floor or platform ·       Working space not to be used for storage ·       90-degree opening of equipment doors or hinged panels ·       Equipment doors not to impede entrance to and egress from the working space ·       Grade, floor, or platform to be as level as practical for the entirety of the working space ·       24-inch wide by 6.5-foot high entrance to and egress from the working space As you can see, the NEC correlates sections with one another when it makes sense. There are, however, a few differences among these sections, one of which is the width of the working space. Section 110.26(A)(2) allows a minimum width of 30 inches for working space, while 110.32 allows a minimum width of 36 inches for that same space. Another difference is the depth of the working space. Table 110.26(A) has varying depths from 3 to 5 feet, while Table 110.34(A) has depths ranging from 3 to 12 feet. All these distances are dependent on the specific condition and nominal voltage to ground. So, for example, for a high-voltage switchgear operating at 13,200 volts to ground, with grounded parts on the opposite side, the depth of working space would be 6 feet, measured from the front of the enclosure or exposed live parts. You will notice that higher voltages and higher hazard conditions require a greater depth of working space for worker safety. Section 110.27 covers the guarding of live parts under 1,000 volts, which in my previous blog could be considered a locked electrical room. For voltages over 1,000 volts, nominal, 110.31, Enclosures for Electrical Installations, would address the electrical room or enclosure for those installations. Some methods of enclosure could be: ·       An electrical vault ·       Electrical room or closet ·       A specific area surrounded by a wall, screen, or fence These methods are designed and constructed according to the nature and degree of hazard associated with the installation. Additional protective measures are required for installations involving walls, screens, or fences that are used to deter access by unqualified persons. These measures may include additional height or barbed wire. These requirements are different from those found in 110.26 and 110.27. Typically, the electrical room or vault access doors are locked to prevent access by unqualified persons, or those doors must be under continuous observation. The doors to these areas are required to open in the direction of egress and be equipped with panic hardware or listed fire exit hardware that opens upon simple pressure. For installations over 1,000 volts, nominal, these locked or monitored rooms, enclosures, or vaults must have a warning sign on the door reading, “DANGER – HIGH VOLTAGE – KEEP OUT.” This sign must also comply with the provisions outlined in 110.21(B) around their durability to withstand exposure to the environment and specific marking requirements. Section 110.27(C) also requires a warning sign for installations of 1,000 volts or less, where there are exposed live parts. It must be placed on the door but is only required to be marked to forbid unqualified persons to enter the electrical room or other guarded area. The wording for the warning sign outside of spaces with over 1,000 volts is much stronger because of the potential exposure to high-voltage electrical hazards. Any exposed live parts adjacent to the electrical room, vault, or enclosure entrance must be suitably guarded. Other exposed parts may require additional means to prevent inadvertent contact with exposed live parts, such as screens, partitions, or fences within the electrical room. Any exposed live parts above the working space are required to be elevated at the distances found in Table 110.34(E) and have permanent ladders for access according to 110.33(B). These codes around working space and electrical rooms are for the protection of qualified persons who may be working on or in this equipment. Stay tuned to NFPA Today for Part 3 in this blog series titled Electrical Rooms, where we will explore electrical vaults. We will look at their construction and some of the requirements for electrical equipment being installed in them.  

This is the first in a series of blogs on electrical rooms Frequently, people associate an electrical room with Article 110 of the National Electrical Code® (NEC®).  More specifically, they associate it with section 110.26. But is that accurate? The answer would be kind of. Section 110.26 deals with what it calls working space about electrical equipment, not electrical rooms. After all, these rooms are sometimes used for other mechanical equipment like furnaces or water heaters, which is why they are sometimes referred to as mechanical rooms. The one thing they are not is storage rooms. The sections within 110.26 are specific to working spaces about electrical equipment that may or may not be within a room. Working space may be in a corridor, basement, exterior, or even a garage. However, the section that could be interpreted to require an electrical room is 110.27, which requires live parts be guarded against accidental contact. One of several methods to accomplish this is by placing electrical equipment in an electrical room or vault. Therefore, most architects design a separate electrical room, or mechanical room, for the main service equipment and mechanical equipment for the building, which is usually less expensive than an electrical vault. In most cases, the room is locked, which helps create a method of control to ensure only qualified persons have access to energized electrical equipment as outlined in 110.26(F). Contained within the electrical room is the working space about the electrical equipment as described in the 2023 NEC, section 110.26(A). This space consists of several parameters, some of which are outlined below. ·       Depth of Working Space is a measurement that considers nominal voltage to ground and if there are grounded parts or exposed live parts across from the equipment. This information lines up with the conditions outlined in Table 110.26(A)(1). To determine this measurement, one must select the condition that applies to the installation. Then measure from exposed parts (soon to be live) or from the face of the enclosure, if live parts are enclosed, extending out the front until the minimum distance within the table is achieved. ·       Width of Working Space is a dimension derived from measuring the width across the front of the electrical equipment. This can be taken from center (15 inches in middle of equipment), from left side of equipment or from right side. No matter the amperage the maximum width will be equal to the width of the equipment but will not be less than 30 inches. ·       Height of Working Space is measured from grade, floor, or platform to a height of 6.5 feet and is the width of the equipment or at least 30 inches and extends out to the depth of the working space. Other items such as luminaries or sprinkler pipes may be above this space, but not within it. ·       Grade, Floor, or Working Platform requires the grade, floor or working platform to be kept clear and that the floor, grade, or working platform be as level and flat as practical for the entire depth and width of the working space for the applicable working space. This is largely because electrical equipment that requires servicing may be in different environments. ·       Entrance to and Egress from Working Space requires at least one entrance of sufficient area to give access to and egress from the working space. Depending on the size of the equipment (see 110.26(C)(2)), the entrance and egress to/from the working space could be 24 inches wide by 6.5 feet high. Open equipment doors must not impede access to and egress from the required working space. If one or more equipment doors are open and access to and egress from the working space is reduced to less than 24 inches wide and 6.5 feet high, the access is considered impeded. Most of us have seen electrical equipment located outside of the electrical room. Sometimes a panel is in a corridor of a school or back hall of a store or even outside. Panels located outside of a building may require other means to guard the live parts from accidental contact and to create a compliant working space. No matter where the electrical equipment that may require servicing is located, all of section 110.26 applies. So, working space and section 110.26 must be accounted for by architects and design professionals in the overall layout and installation of electrical equipment to allow for safe access, operation, and maintenance of that equipment. Stay tuned to NFPA Today for part two in this blog series titled Electrical Rooms, where we will explore the working space requirements for equipment over 1,000 volts, nominal.

As the holidays approach us some may wonder, do I need an electrical inspection to hang my holiday decorative lighting? The answer is maybe. I know, probably not the answer you were thinking. The decision to require an inspection often lies with the authority having jurisdiction (AHJ) along with any applicable laws. The AHJ will likely consider the type of lighting or wiring that is being installed when making the decision. If you are just hanging a few twinkling decorative lights around the house and on trees an inspection might not be needed, but if you are putting on a holiday lighting extravaganza like Clark Griswold in Christmas Vacation, an inspection might be necessary, or probably should be. The 2023 National Electrical Code®, (NEC®), section 590.3(B) permits the installation of temporary holiday decorative lighting and associated wiring, as long as it is not up more than 90-days. This permission has nothing to do with the requirement or wavier of an electrical inspection but does provide the inspector with valuable information. Another question that comes to mind surrounding string lights, the ones that are hung around a patio or along a fence for ambiance, would that require an inspection? Possibly, since the string lights may be considered lampholders by the AHJ and are often left up for longer periods. NEC Article 410, Part VIII, and section 225.24 cover lampholders and their wiring. Because string lights are installed in a more permanent manner, frequently, a fixed and not temporary wiring method is used to supply the power. Section 590.2(B) indicates temporary wiring methods, including lighting, are acceptable only if approved based on conditions of use and any special requirements of the temporary installation. So how is it approved if it is not inspected by a qualified electrical inspector? Simple, it is not approved. So what is the AHJ looking for with temporary wiring or holiday decorative lighting installations? Typically, they are looking for: listing and labeling, sections 590.5, 410.6 wet locations for lampholders, 410.96 Location of outdoor lamps, section 225.25 installation methods, section 225.24, 590.2 So, as the holidays near and we start digging into the boxes in our basements and attics for holiday decor, now is the time to consider your approach to safety. Ensure your holiday decorative lights, string lights, and associated wiring are hung in a safe and code compliant manner and request an inspection where available. By reducing electrical hazards in your home, you can help assure you and your family will enjoy a fun, festive, and safe holiday season. NFPA has free resources to download and share, including a safety tip sheet on outdoor electrical safety, and a safety checklist. For more information, visit nfpa.org/electricalsafety.

Electrical space: the final frontier. “These are the voyages of the electrical inspector.” This plays on a quote from one of my favorite Star Trek movies. Space, especially electrical equipment space in buildings, can seem like it is a final frontier because it is getting harder to come by. Or is it? Prior to the COVID outbreak, buildings were being built to house hundreds, even thousands of employees, so space for electrical and mechanical rooms was at a premium and in tight quarters. Office space, especially when being rented by the square foot, was made a higher priority. With the way that many of us work shifting due to the pandemic, designs of buildings are likely to also start shifting to accommodate the move to a more remote workforce, which occupies less space within buildings. This may cause office spaces to be consolidated, therefore giving more room for electrical and mechanical rooms. Consolidation of space for offices may be occurring, but the change in how we work appears aimed more at having open spaces being converted to conference rooms for team meetings. But no matter what is occurring in the space designated for offices or meeting rooms, the one area that cannot be compromised is the spaces about electrical equipment. There are two types of spaces around electrical equipment mentioned in the 2023 National Electrical Code® (NEC®): working space and dedicated equipment space. Each one has quite different requirements, but all aid in the safety of the worker and longevity of the installation. Working space within the NEC, in general, is comprised of three parts: Depth of Working Space - found in section 110.26(A)(1). This measurement factors in nominal voltage to ground and if there are grounded parts or exposed live parts across from the equipment. Measurements are taken from live exposed parts or from enclosure if live parts are enclosed, out the front until the minimum distance found in Table 110.26(A)(1) is met. Width of Working Space –in section 110.26(A)(2). This dimension is derived by measuring the width across the front of the equipment. This can be taken from center (15 inches in middle of equipment), from left side of equipment or from right side. No matter the voltage or amperage the width will never be less than 30 inches. Height of working Space – addressed in 110.26(A)(3). This is measured from grade, floor, or platform to a height of 6.5 feet and is the width of the equipment or minimally 30 inches. All these spaces combine to form a box, if you will, that is for the qualified worker to occupy when servicing or working on the equipment. This is intended to provide room to move, which is necessary to keep them from bumping into something and possibly getting shocked or causing an arc flash. This area also allows easy access to equipment should a breaker or disconnect need to be shut off quickly. Working space is not to be used for storage according to 110.26(B). In all my years as an inspector I can’t tell you how many times I have had to write that violation during the electrical inspections. These mostly occurred on remodels where circuits and wiring were added to the existing electrical systems. I would politely remind the building owner/occupant that working space was required to help keep the electrical worker safe from exposure to electrical hazards that may be present. New to the 2023 NEC in section 110.26(A)(6) is the requirement that the grade, floor or platform in the working space be clear and as level or flat as practical for the entire required depth and width. The dedicated equipment space in 110.26(E) is just what you would think it would be; space dedicated solely for the installation of electrical equipment. Indoor dedicated electrical space is found in 110.26(E)(1)(a), which electrical inspectors often refer to as the “thumb print” of the equipment plus six feet above the top of the equipment. For example, a panelboard 20-inches wide x 6-inches deep mounted to the surface of the wall at seven feet to the top would have dedicate electrical space extending up to 13 ft above the finished floor. So the overall dedicated space is 20-inches wide x 6-inches deep up to 13 ft. In general, only electrical items are allowed within that space, which might include: raceways (and associated fittings) wireways junction boxes This list is not all inclusive, but an idea of what may be seen within the vicinity of electrical equipment. One exception to the dedicated space requirement is made for suspended ceilings with removable panels. With design limitations imposed on room size, there may be the occasional foreign system intruding into the dedicated electrical space required by section 110.26(E)(1)(a), typically becoming a violation. So, if the system was installed in accordance with 110.26(E)(1)(b), which addresses foreign systems over the dedicated electrical space, there would not be a problem. Remember our example, the top of the dedicated electrical space was 13 feet above finished floor, so the foreign system would need to be higher than 13 feet. If a foreign system is subject to condensation or leaks, the electrical equipment would require protection from such occurrences, which may also mean the system needs to be higher since the method of protection is not allowed within the dedicated electrical space. This space was put into the code to ensure adequate access to the electrical system for the installation of associated parts and to protect the electrical installation from other systems foreign to the electrical system. Electrical space: the final frontier where the voyages of the electrical inspector have explored two of the many requirements of section 110.26(A). Find more information for electrical inspectors by visiting nfpa.org/electricalinspection. You can explore the 2023 NEC by purchasing a printed copy or have NFPA LiNK® beamed to your computer.