Emergency/ Normal Power

[MR120V]

I was recently asked to add some devices to an existing emergency generator in a new parking garage for a client of mine. The new garage was completed in 2007. The garage has a 150 KW generator with tranfer switch and emergency distribution panelboard. During my evaluation I found that there was no seperation between the emergency system and the normal power. All of the lighting and power were run throughout the building in the same conduit system. There was also a trough installed in the electric room that basically intertwined the branch circuits and the feeders with no seperation or designation. Also. the entire parking area had HID lighting with not one restrike throughout the entire 10 floors. Is there some exception to the code I am not seeing? I thought the systems must be kept seperate except as defined by the code in section 700.9 (B). When the contractor was questioned the response back was that they were granted an exception by the city because the building was leased??? Can anyone shed a little light on this?

 

[roger]

Are these generator loads in fact considered and permitted as "Emergency" loads?

If they are "Legally Required" or "Optional Standy" loads there may not be a problem.

Roger

 

[MR120V]

The public and employees use the parking garage. So I guess it is up to the AHJ to classify or is there a set classification for this type of building? Where could I find how this is classified? Life Safety Code?

 

[roger]

You might be able to get some information from the Building Dept being that it is only two years old.

You might also try to locate the original Construction Documents/Record Drawings


Roger

 

[MR120V]

I will. It is just really strange because all the stairways are on emergency power along with one of the 4 elevators also. I am wondering if they are arguing that it is an optional system and not legally required that is how they were able to do it that way.

 

[charlie b]

Unless you are working on a hospital, the NEC is not going to tell us what is, and what is not, an "emergency load." It defines that phrase by saying that an "emergency load" is whatever is so declared by some governmental agency or authority. The one load that I encounter that is most frequently treated as an emergency load is egress lighting. Again, it is not the NEC that calls that an emergency load, but rather the building codes.

One way to avoid having to use a backup generator as the power source to any emergency loads is to use battery-backed egress lights. So if there are no battery backed lights, I would strongly suspect that, when the utility power is lost, the egress paths can only be illuminated through the use of the backup generator. Thus, in your situation, you really would have emergency and non-emergency loads with their wiring improperly run together. That is a violation, not only of the NEC, but also of good safety practices. This is a tragedy in the making.

When the contractor was questioned the response back was that they were granted an exception by the city because the building was leased???

That ranks high on my all-time list of the most absurd statements I have ever encountered.

 

[Pierre C Belarge]

As Roger has stated, this building may not be mandated as an emergency load classification.
The generator may be there for either Legally Required Standby or Optional Standby.

To help understand, I like the FPNs in Art 700 and 701.
In 700, FPN No.3 and in 701, the FPN following 701.2

But...it is totally up to the whoever does the mandating (usually the local municipality) to make the decision.

 

[acrwc10]

When the contractor was questioned the response back was that they were granted an exception by the city because the building was leased???

If this statement is true, exemptions are granted in writing not verbally. So there would be a letter on file with the building dept. If the wiring of separate systems is run in common boxes they should be tagged to notify the next guy who is working on the system of the condition.

 

[MR120V]

Thank you gentlemen...I am going to look into the battery back up lighting and if it is on site. If there is no battery back up it should be assumed that the emergency power is legally required for egress lighting. I will follow up with the city to check on the building code and find out about that beautiful leasing statement!!!