Emergency Generators - Am I missing something?

[steve66]

My understanding is that if an emergency generator serves the emergency egress and exit lighting in a building, any "optional loads" that are connected to the same generator must be supplied from a separate automatic transfer switch. I believe this is what 700.5(D) states:

NEC 700.5(D) - Transfer equipment shall supply only emergency loads.

Am I missing something? Emergency exit and egress lighting are Article 700 loads, correct? If I am correct, hasn't this been in the code for a very long time?

Doing remodel designs, almost every generator I run across serves em lighting and other loads from the same transfer switch. The other loads on the same ATS are often the boiler and circulation pumps.

It's getting old telling clients their existing generator doesn't meet code, and they should either install unit equipment with battery backup, or install another ATS.

 

[iwire]

I agree with your view and see it violated often in existing buildings. Things get added without inspection.

In new work here it wont fly, they expect sperate switches.

 

[dkidd]

Article 517 is an exception that allows one ATS for a demand load less than 150KVA.

 

[steve66]

I agree with your view and see it violated often in existing buildings. Things get added without inspection.

In new work here it wont fly, they expect sperate switches.

Yes, I agree things get added. But I often see this on original plans, stamped and sealed by an engineer.

Article 517 is an exception that allows one ATS for a demand load less than 150KVA.

Yes, for healthcare. Never understood that one. If its not allowed in a typical building, why would it be OK for a hospital where surgery may be happening? But that's another post. Getting back to the topic, I meant to add that a couple of examples I've seen are schools and colleges.

I looked at some older code books, and this requirement wasn't in the 1993 code. Instead there is a requirement to keep emergency lighting branch circuits separate from other loads, and a requirement about providing load shedding for non-emergency loads.

I think its probably in the '99 code book, so I'm guessing the requirement was added in 1996 or 1999. I guess that explains a lot of the older installations.

But it brings up another question: If a portion of a building is remodeled, is the single transfer switch allowed to remain and serve em. lighting in the remodeled area?

Or what if the generator or ATS is replaced? At what point in time does one have to separate the emergency and non-emergency loads?

 

[mgookin]

Yes, I agree things get added. But I often see this on original plans, stamped and sealed by an engineer.



Yes, for healthcare. Never understood that one. If its not allowed in a typical building, why would it be OK for a hospital where surgery may be happening? But that's another post. Getting back to the topic, I meant to add that a couple of examples I've seen are schools and colleges.

I looked at some older code books, and this requirement wasn't in the 1993 code. Instead there is a requirement to keep emergency lighting branch circuits separate from other loads, and a requirement about providing load shedding for non-emergency loads.

I think its probably in the '99 code book, so I'm guessing the requirement was added in 1996 or 1999. I guess that explains a lot of the older installations.

But it brings up another question: If a portion of a building is remodeled, is the single transfer switch allowed to remain and serve em. lighting in the remodeled area?

Or what if the generator or ATS is replaced? At what point in time does one have to separate the emergency and non-emergency loads?

I'll take a stab at it.

A non-conformity is created when a lawfully installed installation (installed with permits & inspections and met code) exists after a code changes which would then not allow it in that condition if installed new today. A non-conformity is vested to the original code and can continue to exist as a non-conformity as long as the non-conformity is not expanded.

Example:
In 1975 you build a building and install a generator with ATS. It feeds emergency and non-emergency loads. In 2010 you want to remodel the building or add on to it.
Scenarios:
A. In your new work you serve only more emergency loads. You make no changes to what's fed in the original part of the building. You do not add any non-emergency loads to the generator. You're fine.
B. In your new work your client insists on having a generator feed additional non-emergency loads which were not fed from the generator previously. Your client needs another generator.

Exception: If your jurisdiction's codes have a 50% rule saying that if you expand or remodel >50% of the building, and you are indeed doing a >50% project, everything needs to meet today's code. In this case your client has the choice of removing all non-emergency loads from the generator or purchasing another generator (or serving emergency loads via batteries).

 

[dkidd]

I looked at some older code books, and this requirement wasn't in the 1993 code. Instead there is a requirement to keep emergency lighting branch circuits separate from other loads, and a requirement about providing load shedding for non-emergency loads.

I think its probably in the '99 code book, so I'm guessing the requirement was added in 1996 or 1999. I guess that explains a lot of the older installations.

98ROP

15- 127 - (700-9(b), Exception No 1 , 700-6) Accept
SUBMITTER. Joel A. Rencsok, City of Phoenix, AZ
RECOMMENDATION Delete Exception No 1 and change the
text of Exception No 1 to read as positive language in Section
700-6
Add a new paragraph at the end of Section 700-6 to read as
follows
Transfer equipment shall supply only emergency loads
SUBSTANTIATION This requirement will help clarify the
intent of the new Section 700-9(c) that emergency equipment be
protected. Allowing other loads as computer equipment and UPS
type equipment to be connected to the same equipment can
disable the total emergency system. Section 700-1 requires that
these systems be limited to life safety only The exception does
not apply to Section 700-9(b) as this section applies to wiring and
does not include the associated equipment requirements
PANEL ACTION Accept
NUMBER OF PANEL MEMBERS ELIGIBLE TO VOTE 19
VOTE ON PANEL ACTION
AFFIRMATIVE 19

 

[steve66]

A non-conformity is created when a lawfully installed installation (installed with permits & inspections and met code) exists after a code changes which would then not allow it in that condition if installed new today. A non-conformity is vested to the original code and can continue to exist as a non-conformity as long as the non-conformity is not expanded.

That sounds reasonable, but at least where I'm at, I don't think this is actually spelled out in any rules or regulations.

Example:
In 1975 you build a building and install a generator with ATS. It feeds emergency and non-emergency loads. In 2010 you want to remodel the building or add on to it.
Scenarios:
A. In your new work you serve only more emergency loads. You make no changes to what's fed in the original part of the building. You do not add any non-emergency loads to the generator. You're fine.

It seems to me like a new addition should have emergency lighting supplied by a source that complies with the current codes. I'm a little more receptive to using the existing source in a remodeled area, even if it doesn't have the separation.

 

[mgookin]

That sounds reasonable, but at least where I'm at, I don't think this is actually spelled out in any rules or regulations.



It seems to me like a new addition should have emergency lighting supplied by a source that complies with the current codes. I'm a little more receptive to using the existing source in a remodeled area, even if it doesn't have the separation.

If you're going to find it, it's going to be in:
1. The adopting statute,
2. An adopting ordinance, and/ or,
3. Chapter 1 of a code (note: It is common for bldg codes to adopt or reference an electric code, so Chapter 1 of a bldg code can apply to application of the electric code because it covers all construction).