Electrical System Classifications

[xptpcrewx]

Can someone please clearly explain which of the below are mutually inclusive/exclusive?

1. Normal Systems
2. Non-Essential Systems?
3. Essential Systems
4. Critical Systems
5. Emergency Systems
6. Legally Required Standby Systems
7. Optional Standby Systems

Also please let me know if I missed any of them. Thanks in advance.

 

[don_resqcapt19]

Some of those terms are exclusive to Article 517...there really is no mixing and matching.

 

[xptpcrewx]

Some of those terms are exclusive to Article 517...there really is no mixing and matching.

For example, can essential systems be considered emergency systems?

 

[jim dungar]

Yes,

Look in article 517, 700, 701, 702, and 708.
There are also other NFPA documents which may come into play.

What type of facility are you working on?

 

[xptpcrewx]

Yes,

Look in article 517, 700, 701, 702, and 708.
There are also other NFPA documents which may come into play.

What type of facility are you working on?

Those articles don't really provide the clarity I am looking for. I understand each system has its own definition, but that doesn't explain which of these are mutually inclusive/exclusive. Also, I am not working on any facility in particular.

 

[jim dungar]

Those articles don't really provide the clarity I am looking for. I understand each system has its own definition, but that doesn't explain which of these are mutually inclusive/exclusive. Also, I am not working on any facility in particular.

You don't think figure 517.30 No.1 (hospital essential systems), 700.2 (exit lighting and essential for life), 701.2 (critical to minimize hazards or for rescue and fire), and 702.2 (systems that do not impact life safety and health) provide some direction?

Definitions like Life Safety, Critical and Optional are always mutually exclusive. However, each type of facility may have different criteria for determining what is essential and what is optional.'

Have you looked at other codes like NFPA-99, NFPA-101, or NFPA-101.

Are you looking for definitions to fit the slang often used improperly in our industry?
In my experience hospital and other industries are trying to move toward Essential Systems, while the NEC continues to refer to Emergency systems.