Jim Dollard has an extensive background in codes and standards. Send questions about the National Electrical Code (NEC) to Jim at firstname.lastname@example.org. Answers are based on the 2020 NEC.
Panic versus fire exit hardware
Where the NEC requires that doors from an electrical equipment room open in the direction of egress, the doors must open with either panic or fire exit hardware. What is the difference?
During the 2020 NEC revision cycle, permission to use “fire exit hardware” was added in each location that previously mandated only panic hardware. For example, see Section 110.26(C)(3). This requirement impacts personnel doors intended for entrance and egress that are less than 25 feet from the nearest edge of the working space of equipment rated 800A or more that contains overcurrent, switching or control devices. These doors are required to open in the direction of egress and be equipped with listed panic or fire exit hardware.
Prior to the 2020 edition, only panic hardware was permitted, leading some AHJs to fail an installation using fire exit hardware. Where these doors are required to be fire-rated assemblies, the hardware must be listed as fire exit hardware. NFPA 101, Life Safety Code, does not permit panic hardware on a fire-rated assembly. Panic hardware is an exit device allowing for quick egress, but it cannot be used on a fire door. Fire exit hardware is a device tested for panic and fire conditions. It is required to be used on fire doors where panic hardware is required.
Equipotential bonding and hot tubs
Do we need to install equipotential bonding of walking surfaces for an outdoor hot tub? I get conflicting answers when contacting different townships.
It is important to understand that hot tubs/spas are specifically addressed in Part IV, Spas and Hot Tubs, in Article 680. The first section in this part, 680.40, requires that spas and hot tubs comply with parts I and IV of Article 680. This gets confusing, because the requirements for outdoor and indoor hot tubs/spas (680.42 and 680.43) require compliance with parts I and II of Article 680. One would think that “indoor and outdoor” cover all the bases. The requirements in 680.40 are unnecessary and confusing.
Section 680.42 addresses outdoor installations. See 680.42(B), which does not require equipotential bonding of perimeter surfaces (as required in 680.26(B)(2)), provided that the hot tub/spa: (1) is listed, labeled and identified as a self-contained spa for aboveground use; (2) is not identified as suitable only for indoor use; (3) is installed in accordance with the manufacturer’s instructions and located on or above grade; and (4) the top rim of the hot tub is at least 28 inches above all perimeter surfaces within 30 inches measured horizontally from the hot tub/spa.
Indoor hot tubs are addressed in 680.43. See Exception No. 2, which exempts the hot tub/spa from the perimeter equipotential bonding requirements in 680.26(B)(2), provided it is a listed self-contained hot tub/spa installed above a finished floor.
Type NM cable support
At a recent code seminar, we were informed that “Romex” can be supported within 18 inches of a box. We did that and had to go back and add staples at 12 inches. Did that change again? Additionally, how can we identify ty-wraps that can be used for securement and support?
The revision that you are referencing did not extend the minimum support requirement from 12–18 inches, it simply added an allowance to “loop up to 6 inches” of Type NM cable to allow for rework, etc. See Section 334.30, which contains requirements for securing and supporting Type NM cable.
The cable assembly must be supported and secured at intervals not exceeding 4½ feet and within 12 inches of every cable entry into enclosures such as outlet and junction boxes, cabinets or fittings. The length of Type NM cable between the cable entry and the closest cable support (staples typically at 12 inches) cannot be longer than 18 inches. This section also prohibits stapling Type NM cable on edge—it must be stapled flat against a surface or support. Section 334.30 requires that where Type NM cable is secured and supported by cable ties, they must be listed and identified for securement and support. Cable ties meeting this requirement are identified as Type 2S or Type 21S. The “S” means they are recognized for securement and support.
Fire pumps, transfer of power
In an effort to reduce cost, the design for a fire pump in a large commercial building showed an outdoor transfer switch for the service and generator supplies. The load side of the transfer switch went directly to the fire pump controller. We understand this is not permitted in the NEC. The owner asked, why?
Section 695.3(F) requires that where an individual source and an alternate source are installed (see 695.3(B) for example), the transfer of power to the fire pump controller must take place within the fire pump room. This requirement exists to increase power reliability to the fire pump. As described in your question, there was a single set of conductors supplying power to the fire pump controller. If those conductors were affected by fire or other hazards, the power source to the fire pump is lost. See Section 695.3(E), Arrangement, which mandates that all power supplies be located and arranged to protect against damage by fire from within the premises and exposing hazards. This section further mandates that multiple power sources (individual and alternate sources) be arranged so that a fire at one source does not cause an interruption at the other. It is all about reliability.
It is important to note that NFPA 20, Standard for the Installation of Stationary Pumps for Fire Protection, has purview over the performance of electric-driven fire pumps. The Code only contains installation requirements written in NEC style, to meet the performance requirements seen in NFPA 20. Requirements for arrangement of power supplies are located in NFPA 20:9.1.4 and transfer of power in 20:9.6.4.
Detached garage, grounding electrode system?
Now that a garage for a single-family dwelling unit is required to be supplied with a branch circuit for only receptacles supplying each vehicle bay, a separate branch circuit is required for lighting and garage door openers. Does this mean that now a detached garage is required to have a grounding electrode system installed?
No. Section 210.11(C)(4) requires at least one 120V, 20A branch circuit to supply receptacle outlets required by 210.52(G)(1) for attached and detached garages with electric power. In general, this branch circuit is permitted to supply only the receptacle outlets installed in each vehicle bay, which cannot be installed more than 5½ feet above the floor.
An exception permits this branch circuit to supply readily accessible outdoor receptacle outlets. As stated in your question, lighting and power for the garage door openers require a separate branch circuit. A multiwire branch circuit can be installed to supply both branch circuits. See Section 210.4(A), which permits a multiwire branch circuit to be considered as multiple branch circuits. The general rule for a building/structure (detached garage in this case) supplied by a feeder or branch circuit is that a grounding electrode system must be installed in accordance with 250.32(A). However, there is an exception for the requirement for a grounding electrode system for a building/structure supplied by a single branch circuit, including a multiwire branch circuit, that includes an equipment grounding conductor. It is important to note that a disconnecting means is required either inside or outside the garage. If inside, it must be located nearest the point of entrance of the conductors. In this case, a 2-pole snap switch could be used. See sections 225.31 and 225.32.