hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
I have high rise building in which their is emergency generator. The generator has three ATS. One is Life and Safety, second is Standby and third is Optional Standby.
For Life and Safety portion NEC 2017 Section 700.3(F) which says:
“(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.
EXCEPTION the permanent switching means to connect portable or alternate source of power for the duration of maintenance or repair shall not be required where any of the following conditions exists:
1. All process that rely on the emergency system source are capable of being disabled during maintenance or repair of the emergency source of power.”
Designer is saying that install complies with 700.3(F) exception no. 1. All process that rely on emergency source are capable of being disable during maintenance or repair of the emergency power source so this section does not apply.
However, The life and safety branch ofcourse has egress lights, corridors light and all life safety load which need to remain on are Not on battery and only backup source is generator and if power goes out and if emergency generator is under maintenance and no temporary source of power is provided i dont see how they are capable of being disable.
So i disagree but disable word can have meaning and intent is not known. Any load is capable being disable from power source you know just disconnect the cables and its disabled.
Questions
1. Does anyone know the intent of the 700.3(F) exception no. 1 or provide opinions as to what exactly is it saying?
2. Would you agree with designer no temp source of power required or with me temp source of power is required?
3. What does in your opinion disable mean in 700.3(F) exception no.1?
For Life and Safety portion NEC 2017 Section 700.3(F) which says:
“(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.
EXCEPTION the permanent switching means to connect portable or alternate source of power for the duration of maintenance or repair shall not be required where any of the following conditions exists:
1. All process that rely on the emergency system source are capable of being disabled during maintenance or repair of the emergency source of power.”
Designer is saying that install complies with 700.3(F) exception no. 1. All process that rely on emergency source are capable of being disable during maintenance or repair of the emergency power source so this section does not apply.
However, The life and safety branch ofcourse has egress lights, corridors light and all life safety load which need to remain on are Not on battery and only backup source is generator and if power goes out and if emergency generator is under maintenance and no temporary source of power is provided i dont see how they are capable of being disable.
So i disagree but disable word can have meaning and intent is not known. Any load is capable being disable from power source you know just disconnect the cables and its disabled.
Questions
1. Does anyone know the intent of the 700.3(F) exception no. 1 or provide opinions as to what exactly is it saying?
2. Would you agree with designer no temp source of power required or with me temp source of power is required?
3. What does in your opinion disable mean in 700.3(F) exception no.1?
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