700.27 Coordination

Status
Not open for further replies.
D

dbravo

Member
Hello,
I have an existing emergency power dist. system with life safety & non-life safety loads. There is a requirement to add new life safety branch circuits. The existing emer. pwr system currently does not have overcurrent devices selectively coordinated.

Once we modify the existing system, is a coordination study required per NEC 700.27? The system was designed and constructed prior to 2005 NEC.
Thanks in advance.
 
Hard to say just how your jurisdiction handles that kind of code change.

Some places are reasonable about it and others not.

I think you could call whoever the AHJ is and find out. Usually the inspector is not the best place to ask this kind of question because they probably just don't know and rather than say that they will tell you what they think, and it is as likely to be wrong as what you might think about it.

I would get it in writing in any case.

Does this work require a permit? If not, it should not be an issue at all.

I think there is going to have to be some interaction with the owner on this as well. This could result in a lot of extra expense to him, so before you go talking to anyone else you should bring it up with the owner. Your primary duty is to the guy footing the bill. Don't start by screwing him over.
 
Thanks for the reply,

Most likely I would have to go to the AHJ. The work does require a permit and the owner is aware of it and has directed me to research if a selective coord. study is required because it can be costly.

I was hoping that there is some hardship issue within the code that does not selective coord. is not permitted.

Thanks again
 
While you're at it, if coordination is needed, ask the AHJ what does selectively coordinated mean?

In NYC, they recently adopted another change to the NEC:

For the purposes of this code two overcurrent protective devices shall be deemed selectively coordinated if their respective time-current characteristic curves do not intersect at a time of 0.1 seconds (6cycles on 60 Hz systems) or longer.
 
Another thing to find out is whether selective coordination would have to be demonstrated for both the normal distribution system and the emergency distribution system. In my area, we don't have to show coordination with the system being powered via the utility.

By the way, is this a hospital? If not, the phrase "life safety" does not apply. The NEC only uses that phrase in article 517.
 
Charlie B,

Thanks for your response. No it is not a hospital it is a industrial facility.
I thought egress lighting, fire alarm, etc is considered life safety?

Is there any NY legislation that states that where the emergency system was installed prior to NEC 2005 is considered "grandfathered"?

Please help!
 
dbravo said:
I thought egress lighting, fire alarm, etc is considered life safety?
Click to expand...
It is not uncommon for that phrase to be used. But the way the NEC looks at things, you start by noting that it is a building code that requires egress lighting to be available, if the utility power source is lost. The fact that an official, governmental agency (i.e., the one that adopted the building code) has thereby declared that egress lights are an emergency load is what enables us to put the egress lighting on the emergency source. Take a look at the way NEC 700.1 (second paragraph, first sentence) describes what an emergency system is.

But if you want to know what the NEC has to say about "life safety loads," you have to look in article 517. The definition of the phrase is not in article 100, it is in 517.2.
 
Ron, you are correct. On June 28, 2011, New York City Mayor Michael R. Bloomberg signed Introductory Number 64-A (Intro 64-A). Intro 64-A is legislation passed by the City Council on June 14, 2011 that updates the current NYC Electrical Code by adopting the 2008 National Electrical Code with local amendments.
Below is the link.
I still cant find anywhere where it is required to perform a coordination study for an existing system installed prior to NEC 2005.

Just trying to gather my info before I go to the local AHJ.

Dean

http://nlvca.org/forum/showthread.php?t=1853

ron said:
While you're at it, if coordination is needed, ask the AHJ what does selectively coordinated mean?

In NYC, they recently adopted another change to the NEC:

For the purposes of this code two overcurrent protective devices shall be deemed selectively coordinated if their respective time-current characteristic curves do not intersect at a time of 0.1 seconds (6cycles on 60 Hz systems) or longer.
Click to expand...
 
Charlie B,

Thanks for the clarification. I am looking for something similiar to what the state of WA legislation has passed in this same situation.

see link and excerpt below.

http://apps.leg.wa.gov/wac/default.aspx?cite=296-46B-700

(5) The requirements for selective coordination described in NEC 700.27 are not required where the emergency system was installed prior to June 1, 2006. For new emergency systems that are supplied from an existing emergency system installed prior to June 1, 2006, the new portion of the emergency system must comply with NEC 700.27. The ground fault sensing function of overcurrent protective devices will only be required to selectively coordinate with the ground fault sensing functions of other overcurrent protective devices.
 
Status
Not open for further replies.
Top