2017 Changes to the National Electrical Code Require Secondary Means to Shutdown Prime Mover

The National Electrical Code 2017 Edition
Important Changes to the 2017 National Electrical Code include a Generator Prime Mover Shutdown Means

Significant changes were made to article 445.18 in the 2017 edition of the National Electrical Code (NEC). This article was formerly titled “Disconnecting Means Required for Generators” in the previous 2014 Revision. The National Fire Protection Association (NFPA) issues a new edition to the NEC every three years.

In the 2017 edition, the title was changed to read “Disconnecting Means and Shutdown of Prime Movers. The article was split into three sections; 445.18(A) for Disconnecting Means and 445.18(B) for Shutdown of Prime Mover. Section 445.18(C) clarifies the operation of synchronous parallel generators and the disconnecting means necessary.

Note: The Prime Mover is the engine that drives the alternator (generator).

The intent of article 445.18(A) is closely aligned with the previous 2014 edition regarding the disconnecting means for the generator.

445.18(B) states, “Generators with greater than 15kW rating shall be provided with an additional requirement to shut down the prime mover. This additional shutdown means shall be located outside the equipment room or generator enclosure and shall also meet the requirements of Sec. 445.18(B)(1) and (B)(2).”

Prime Mover Shutdown for Standby Generators

Red Emergency Stop Button with Decal
The Prime Mover Shutdown Means or Emergency Stop shuts off the generator engine.

The changes to article 445.18 require that new generator installations and upgrades to existing installations provide a means to shut down the prime mover (engine) in such a way that it cannot be restarted without a manual reset of the generator start circuits. As local code authorities adopt the 2017 editions of the code, they will begin enforcing this new requirement on all new installations and upgrades to existing installations.

Standby generators have integrated microprocessor-based controllers which include automatic startup in the event of a power outage. The “manual reset” wording of the revision will likely require changes to the programming for most standby generator controllers—usually accomplished by a firmware update provided by the generator manufacturer. Factories will apply the new firmware updates to new units coming off the line. Installers will update the firmware on units shipped from existing stock in warehouses.

Generator Manufacturers have begun to produce Shutdown Kits that bring their standby generators into compliance with the new NEC changes.

In an emergency, pushing the stop button or moving the switch to the off position will immediately shutdown the generator. The controller will display a message which must be cleared before the generator will start again which meets the manual reset requirement. In the case of an On/Off switch, moving the switch back to the on position will not restart the generator or allow it to start.

Generac Engine Shutdown Add-On Kit

Bright red generac E-Stop button and switch
Generac E-Stop is compatible with the new Generac Generator Shutdown Kit

Generac Power Systems supplies their Engine Shutdown Add-On Kit to bring Generac standby generators into compliance with NEC article 445.18(B). Installation may require a controller firmware update. Moving the switch to the “OFF” position while the standby generator unit is running causes an immediate shutdown and sets a controller alarm which requires clearing before the generator can be started.

The add-on kit is compatible with the following Generac standby generators. 15kW to 60kW liquid-cooled standby generators, 9-kilowatt to 22-kilowatt Guardian, Synergy, and EcoGen air-cooled standby generators, Guardian three-phase generators, and Protector Diesel Generators already equipped with the Optional Emergency E-Stop Switch, and all other Protector series liquid cooled generators.

Engine Shutdown Add-On Kits are compatible with Evolution 1.0 / Sync 2.0 controllers, and Evolution 2.0 / Sync 3.0 controllers.

The kit includes two rocker switches with wiring and crimp connectors plus two decals. Installation on the exterior of the standby generator cabinet meets the new NEC article 445.18(B).

Kohler Power Systems Emergency Stop Kit

Kohler Emergency Stop Kit
Kohler’s Emergency Stop Kit is easy to install and comes with instructions.

The Kohler Emergency Stop Kit is a large red emergency-stop pushbutton switch that installs on the exterior of Kohler air-cooled standby generators. Pushing the button allows you to shut down the generator in an emergency without opening the cabinet or accessing the generator remotely.

Emergency Stop Kits by Kohler Power Systems are compatible with 14RESA(L) and 20RESA(L) generator models.

Installation is simple. The kit includes one large red pushbutton switch, a wiring harness with connectors, a bright yellow decal that identifies the pushbutton as an emergency stop, and installation instructions.

Other Manufacturers

Information provided as it becomes available. Please check back for updates.