Making the Code at Home

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shutterstock / Christian Delbert

Even though the 2020 National Electrical Code was just issued in September 2019 and many states will not adopt the new Code until this year, electrical contractors should be aware of the major changes that will affect most residential services. Some changes in Article 230 came about based on input from first responders who may need to disconnect power to the home without waiting for the electrical utility company to pull the meter or disconnect power at the utility pole.

A new Section 230.85 was added to require one- and two-family dwelling units to have all service conductors terminate in disconnecting means by having a short-­circuit current rating equal to or greater than the available fault current, which has always been required. It also requires installation in a readily accessible outdoor location, which is new. If more than one disconnect means is provided, the disconnects must be grouped together as required by 230.72.

The new requirement is that each disconnecting means has one of the following three markings on it: 

  1. Emergency Disconnect, Service Disconnect
  2. Meter disconnects installed in accordance with 230.82(3) shall be marked as “Emergency Disconnect, Meter Disconnect, Not Service Equipment”
  3. Other listed disconnect switches or circuit breakers on the supply side of each service disconnect that are suitable for use as service equipment shall be marked “Emergency Disconnect, Not Service Equipment.”

All marking for these emergency disconnecting means are required to comply with 110.21(B).

New subsection 230.82(10) has been added to cover the “emergency disconnecting means” installed on the supply side of the service disconnecting means. This text states that emergency disconnects installed in accordance with 230.85 are permitted to be installed on the supply side of the service disconnecting means, if all the metal housings and service enclosures are grounded in accordance with Part VII in Article 250 and bonded in accordance with Part V of Article 250.

There may be some confusion in the electrical industry with using the phrase “emergency disconnecting means” as it relates to these one- and two-family disconnecting means, since Article 700 applies to emergency systems and would not apply to these particular installations. Renaming these disconnecting means in the next Code cycle as “First Responder Disconnecting Means” or a similar name may be a solution. In addition, 230.82(3) already covers meter disconnecting means, including the requirements for compliance with parts V and VII of Article 250 and the short-circuit current ratings to be equal to or greater than the available fault current.

The reason for the meter disconnecting means in 230.82(3) and now in 230.82(10) is to provide the utility company with a disconnecting means to turn the power off when pulling or installing the meter in the can. In many cases, the utility companies lock these disconnecting means to ensure no one can tamper with the meters. It appears that Code-Making Panel-10 now recognizes the meter disconnect to be an emergency disconnect that can be located outside but may not be the service-main disconnecting means. If the meter disconnect is an emergency disconnecting means, is the main disconnecting means then permitted to be inside the home where compliance with 250.24(A)(5) may become an issue?

Many large electrical services supplying single-family dwellings are located in electrical service rooms within the home and will require a large disconnecting means to be installed outside. In regions where snow and inclement weather is normal during winter, locating the service main inside the building is common and will now require a main disconnecting means outside with all panelboards inside in compliance with 250.24(A)(5) with the neutral isolated from the equipment grounding system. Service changes on older homes will now require a main disconnecting means to be located outside, unless it is permitted outside with the main located inside the home.

A new Section 230.67 requiring surge protection for dwelling units has also been added. This surge protective device (SPD) must be an integral part of the service equipment or be located immediately adjacent to it. An exception has been added that permits the SPD to be located at the next level distribution downstream toward the load. Where service equipment is replaced for existing homes, surge protective equipment must be installed.

Some of these new requirements already may have been implemented in your area by local jurisdiction amendments to the NEC or may be a common practice already due to the local year-round weather conditions.

About the Author

Mark C. Ode

Fire/Life Safety, Residential and Code Contributor

Mark C. Ode is a lead engineering associate for Energy & Power Technologies at Underwriters Laboratories Inc. and can be reached at 919.949.2576 and Mark.C.Ode@ul.com.

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