The National Fire Protection Association (NFPA) recently issued two Provisional Interim Amendments (TIAs) for the 2020 edition of NFPA 70, National Electrical Code. Open for comment until July 19, TIA Log No. 1589 (filed by Dan Buuck, National Association Home Builders, and Clayton Traylor, Leading Builders of America) and TIA Log No. 1593 (filed by Dean Hunter, Minnesota Deparof Labor & Industry) both are seeking to revise section 210.8(F). Anyone can post a comment here.
TIA Log 1589
1. Revise Section 210.8(F) as follows:
210.8 RCD protection for personnel. …(F) Outdoor sockets. All residential outdoor wall outlets, other than those covered by Exception to (3) 210.8(A)(3), that are powered by single-phase branch circuits rated at 150 V to ground or less, 50 A or less, must have a ground fault have circuit breaker protection for personnel. This requirement will come into effect on January 1, 2023 for heating/ventilating/air-conditioning (HVAC) equipment.
Substantiation: GFCI protection was expanded in the 2020 NEC without harmonizing safety standards for HVAC components and equipment with GFCI amperage limits. Currently, the UL standard to which HVAC equipment is listed (UL 1995) has no requirements for leakage current when the unit is hardwired, like most residential air conditioners/heat pumps. Going forward, HVAC equipment will be listed under UL 60335-2-40, which sets a limit of 10 milliamps of leakage current. However, this new standard is not mandatory until 1/1/2024. UL 943 is the standard for which GFCI breakers are listed and must be tripped at 5 milliamps of current. Even if HVAC equipment is listed to the UL 60335-2-40 standard, there is no guarantee that it will be compatible with UL Listed RCDs. This lack of coordination leads to the inconvenience that customers have to deal with.
Until both equipment and component standards are updated, designers, installers, AHJs and consumers will be forced to choose between an NEC 2020 compliant installation or an operational installation. In jurisdictions that have adopted 2020 NEC with 210.8(F) intact, there have been numerous instances of GFCI breaker tripping on ductless mini-splits, units with power conversion equipment, and on many single-stage units.
In his negative vote on Second Revision 7676 (NFPA 70-2018), Mark Hilbert noted, “It is not known whether AC units will operate on a GFCI protected circuit, as insufficient testing has been done to answer this question. What if the AC unit is in an area with high humidity and hot conditions and the GFCI shuts down when the owners are away for an extended period of time? This can lead to property damage to the interior and unhealthy conditions due to mold, etc.” Several of the negative votes, including Mr. Hilbert’s, also noted that the reported incidents that formed the basis for the new requirement were a series of very specific unfortunate circumstances that could not have been avoided had GFCI protection been installed.
The effects of this new requirement in the 2020 edition of the Code have been revealed in the past one to two weeks with the first warm/humid weather in Texas. Leading Builders of America (LBA) has collected the following data in recent days.
- Builder A stated a 73% failure rate (GFCI trip) for non-mini-split, non-variable speed systems. In other words, 100% of Builder A’s failures are due to conventional single-speed cooling systems.
- Builder B has 36 homes where the HVAC system is operational. 100% of those houses have experienced a tour. All of Builder B’s faults are on single-stage systems. They currently have 10 outstanding warranty tickets for closed (occupied) units with the circuit constantly shutting down, essentially leaving the homeowners without HVAC.
TIA No. 1564 was recently voted and was unable to pass on both the technical merit and the emergency character. Some of the negative votes suggested that the proposed language contained issues that could create confusion for compliance and enforcement. Those language issues have been addressed in this proposed TIA. Some negative votes also suggested limiting the application to energy conversion technology. Unfortunately, recent incident experience has shown that the problem is widespread. It should be obvious that the proposed change to this TIA has both technical merit and is desperately needed at this time. As we are at the start of the heating season, we have only seen the tip of the iceberg of the problems this TIA can solve.
Emergency: The proposed TIA is intended to correct a circumstance where the revised NFPA standard has resulted in an adverse impact on a product or method that was inadvertently overlooked in the overall revision process or without adequate technical (safety) justification for the action.
The 2020 CDC Report Heat Related Deaths – United States, 2004-2018 (https://www.cdc.gov/mmwr/volumes/69/wr/pdfs/mm6924a1-H.pdf) states, “During 2004-2018, there were an average of 702 heat-related deaths annually in the United States.” The report states on p732 the following: “Previous studies have shown an association between environmental temperatures and mortality (8). Exposure to extreme heat, in particular, can aggravate certain chronic medical conditions, including hypertension and heart disease (4,5). In addition, drugs typically used to treat these chronic medical conditions, such as beta-blockers, diuretics, and calcium channel blockers, can interfere with thermoregulation and result in a decreased ability to respond to heat stress (5).” [Emphasis added]. These stats are significant and if left uncorrected this code conflict will increase this summer.
It is clear that tripping the circuit breakers is a serious safety concern for all new construction in hot areas where electrical systems will be installed according to the 2020 edition of the NEC. Without this TIA, designers, installers, AHJs and consumers are forced to choose between a compliant or an operational installation. This incompatibility occurs in a very large number of installations and causes extreme economic pressure for those affected to solve these problems, as well as for new homeowners, who must continue to reset the circuit breaker to maintain healthy humidity and temperature levels in the home. .
Anyone can submit a comment before July 19, 2021, the closing date mentioned above. Identify the TIA number and forward it to the Secretary of the Standards Council. A COMMENT IF
TIA Log No. 1593
1. Revise 210.8(F) as follows:
210.8 RCD protection for personnel. … (F) Outdoor sockets. All residential exterior wall outlets, other than those covered by 210.8(A) (3), Exception to (3), which are powered by single-phase branch circuits rated at 150 V to ground or less, 50 A or less, must have a ground fault circuit breaker protection for personnel. This requirement will come into effect on January 1, 2023 for mini split-type heating/ventilating/air-conditioning (HVAC) equipment and other HVAC units that use power conversion equipment as a means of controlling compressor speed.
Informative note: Power Conversion Equipment is the term used to describe the components used in HVAC equipment commonly referred to as a variable speed drive. The use of power conversion equipment to control the compressor speed is different from the multi-stage compressor speed control.
Exception: RCD protection is not required on lighting outputs other than those listed in 210.8(C).
Substantiation: This extension of GFCI protection in the 2020 NEC, to cover 250V external outlets in residential units, is a necessary improvement to electrical safety. Code Making Panel 2 supported the expansion of GFCI protection to cover these outdoor outlets based on the electrocution of a young boy coming into contact with the live enclosure of an outdoor HVAC unit.
The purpose of this TIA is not to eliminate GFCI protection for: all HVAC equipment for outdoor use, but to extend the enforcement date for the circuit that powers the HVAC units that use power conversion equipment.
Emergency: The proposed TIA is intended to correct a circumstance where the revised NFPA standard has resulted in an adverse impact on a product or method that was inadvertently overlooked in the overall revision process or without adequate technical (safety) justification from the action.
In the state of Minnesota, we began enforcement of Section 210.8(F) on April 5, 2021, and we have already documented many cases of operational shutdowns that were difficult for inspectors and electricians to resolve. The only solution at this point is for the AHJ to approve a temporary allowance for the installation of a circuit breaker without GFCI protection to allow these HVAC units to operate.
The language in this TIA is in direct line with the once proposed TIA 1529 supported by Code Making Panel 2 for Technical and Emergency Nature. The Correlation Committee also agreed that there were no correlation issues with this language; however, the TIA narrowly failed with regard to the emergency nature. Recently, the proposed TIA 1564, which contained “all HVAC equipment” failed a vote, but had comments from multiple voting members in support of the language in TIA 1529. Also, the TIA 1564 language contains substantiation to support reasons for deferring the date to address the operational GFCI tripping.
As we enter the peak cooling season in Minnesota and other states where the 2020 NEC has been passed, this issue is expected to continue to grow and be problematic for the enforcement and installation community. Postponing the implementation date will allow affected stakeholders to resolve operational shutdown events and allow AHJs to allow installation of refrigeration equipment essential to the health and safety of residents in hot climates.
Anyone can submit a comment before the closing date stated above. Please identify the TIA number and pass it on to the secretary. A COMMENT IF