A new section was added to 700 section 700.3(F). If you have a required emergency generator system, and you have to take it out of service for repairs or maintenance you have to have temporary or portable means to maintain the emergency backup system. There are many ways to achieve this backup to the backup system, a Kirk key systems and Cam locks systems are some of the means to achieve this backup, but that will be up to the design professional. In the 2017 when designing a system you will be required to meet the Code requirements from 700.3(F) for the emergency backup system..
700.3(F) Temporary Source of Power for Maintenance or Repair of the Alternate Source of Power.
If the emergency system relies on a single alternate source of power, which will be disabled for maintenance or repair, the emergency system shall include permanent switching means to connect a portable or temporary alternate source of power, which shall be available for the duration of the maintenance or repair. The permanent switching means to connect a portable or temporary alternate source of power shall comply with the following:
(1)Connection to the portable or temporary alternate source of power shall not require modification of the permanent system wiring.
(2)Transfer of power between the normal power source and the emergency power source shall be in accordance with 700.12.
(3)The connection point for the portable or temporary alternate source shall be marked with the phase rotation and system bonding requirements.
(4)Mechanical or electrical interlocking shall prevent inadvertent interconnection of power sources.
(5)The switching means shall include a contact point that shall annunciate at a location remote from the generator or at another facility monitoring system to indicate that the permanent emergency source is disconnected from the emergency system.
It shall be permissible to utilize manual switching to switch from the permanent source of power to the portable or temporary alternate source of power and to utilize the switching means for connection of a load bank.
Informational Note: There are many possible methods to achieve the requirements of 700.3(F). See Figure 700.3(F) for one example.
Exception: The permanent switching means to connect a portable or temporary alternate source of power, for the duration of the maintenance or repair, shall not be required where any of the following conditions exists:
(1) All processes that rely on the emergency system source are capable of being disabled during maintenance or repair of the emergency source of power.
(2) The building or structure is unoccupied and fire suppression systems are fully functional and do not require an alternate power source.
(3) Other temporary means can be substituted for the emergency system.
(4) A permanent alternate emergency source, such as, but not limited to, a second on-site standby generator or separate electric utility service connection, capable of supporting the emergency system, exists.
Till next time be safe work safe
Jake