Emergency Generator

[ken44]

Is there an NFPA restriction regarding the application of an Emergency Generator that is designated for Life Safety Systems, concerning whether or not it can also have other loads on it that are not Life Safety Systems?

 

[dkidd]

The generator can supply other loads, but additional transfer switches will be needed unless the facility falls under NEC 517 exceptions.

 

[iwire]

If it is truly an emergency generator you will have to do as mentioned above if you want to supply optional loads.

See 700.9(B).

 

[ken44]

I was sent this information, it looks good to me.
Optional loads are allowed according to NFPA under the following provisions:

Per NFPA (National Fire Protection Association) - 110 Chapter 7.1.5

When the normal power source is not available, the EPS (Emergency Power Supply) shall be permitted to serve optional loads, provided that the EPS has adequate capacity or automatic selective load pickup and load shedding are provided as needed to ensure adequate power to 1) the Level 1 loads, 2) the Level 2 loads and 3) the optional loads, in that order of priority. When normal power is avaialble, the EPS shall be permitted to be used for other purposes such as peak load shaving, internal voltage control, load relief for the utility providing normal power, or co-generation.

Level 1 systems (loads) are defined as: those systems required when failure of the equipment to perform could result in loss of human life or serious injuries. [fire alarm, fire pump, smoke removal, lighting, etc]

Level 2 systems (loads) are defined as: those systems required when failure of the EPSS to perform is less critical to human life and safety and where the authority having jurisdiction shall permit a higher degree of flexibility than that provided by a level 1 system. [ventilation and other not as critical type systems]

 

[iwire]

Ken, per Article 700 the only way you can supply optional loads from a emergency source you must keep it separate, that means separate transfer switches, distribution equipment, feeders and branch circuits.

They do not want a fault on the optional items taking out a breaker supplying emergency loads.

These is the first thing to worry about, then you can get into load shedding schemes.

 

[steve66]

I was sent this information, it looks good to me.
Optional loads are allowed according to NFPA under the following provisions:

Per NFPA (National Fire Protection Association) - 110 Chapter 7.1.5

When the normal power source is not available, the EPS (Emergency Power Supply) shall be permitted to serve optional loads, provided that the EPS has adequate capacity or automatic selective load pickup and load shedding are provided as needed to ensure adequate power to 1) the Level 1 loads, 2) the Level 2 loads and 3) the optional loads, in that order of priority. When normal power is avaialble, the EPS shall be permitted to be used for other purposes such as peak load shaving, internal voltage control, load relief for the utility providing normal power, or co-generation.

Level 1 systems (loads) are defined as: those systems required when failure of the equipment to perform could result in loss of human life or serious injuries. [fire alarm, fire pump, smoke removal, lighting, etc]

Level 2 systems (loads) are defined as: those systems required when failure of the EPSS to perform is less critical to human life and safety and where the authority having jurisdiction shall permit a higher degree of flexibility than that provided by a level 1 system. [ventilation and other not as critical type systems]

The definition of EPS only includes the generator. So your generator can serve non-emergency loads, but as Iwire said, you have to have a separate transfer switch to serve the non-emergency loads.

If you are under the 2008 NEC, your emergency loads must also be served from a separate switchboard section than the non-emergency loads, or you have to tap off ahead of the switchboard for the emergency loads.

That's in the NEC article 700. Not sure exactly which paragraph.

If you are under the 2005 or earlier NEC, not everyone agrees on exactly where you can pick up the non-emergency loads.

 

[dkidd]

but as Iwire said, you have to have a separate transfer switch to serve the non-emergency loads..

I was first : )

or you have to tap off ahead of the switchboard for the emergency loads.

I'm pretty sure that taps ahead have not been allowed for several Code editions.

 

[steve66]

I was first : )

Opps, OK, I'll give credit where due

I'm pretty sure that taps ahead have not been allowed for several Code editions.

I think the 2008 version is the first one that actually said a "separate vertical switchboard section.....". In the 2005, I think it just said that emergency loads "should be kept completely separate from other loads". Different people interperted that in different ways.

But my 2005 book is out of reach, so I haven't actually double checked that.