code article?

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steveng

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i have asked about this before but , i need some help with the code intereptation. i believe this would be an optional standy by system.

we have 28kw 480 3ph gen we want to use to supply power,lighting ,hvac for an area (3 rooms), inside a school bldg, college. it will house the campus police/ and serve as disaster response center in emergency situations, primarily for the schools use, however, this is not legally required.

the gen is feeding an automatic transfer switch/ asco listed use 100 amp 480 3ph

does article 702 cover this installation?

thanks
 
article702.jpg
 
steveng said:
i have asked about this before but , i need some help with the code intereptation. i believe this would be an optional standy by system.

we have 28kw 480 3ph gen we want to use to supply power,lighting ,hvac for an area (3 rooms), inside a school bldg, college. it will house the campus police/ and serve as disaster response center in emergency situations, primarily for the schools use, however, this is not legally required.

the gen is feeding an automatic transfer switch/ asco listed use 100 amp 480 3ph

does article 702 cover this installation?

thanks
Click to expand...




702 is intended for where life safety does not depend on the performance of the system. such as a farm or comfort.
In your case, as a disaster response center. I would interpet that to mean lives could be directly saved due to having power. If nothing else just to be able to comunicate. Mass text messages or emails to students. Dispatch to rescue.
I would leave the heat on the generator but not the ac. You would want to conserve fuel. Your generator should idle down when it does not have a large load. This will conserve fuel. In a disaster no body knows how long it will take to get fuel.
If you are relying on public gas. What if the disaster was an explosion that took out the utilities gas lines. You might want to consider diesel.
If you are in charge of this system also have a small standby generator.
In case the large one fails.
You did say this would be the center for disaster relief.
 
buckofdurham said:
702 is intended for where life safety does not depend on the performance of the system. such as a farm or comfort.
Click to expand...

That is exactly right and it is why the NEC is very strict about supplying 'optional' loads with an emergency system. They don't want a short circuit in someones coffee maker to drop out a breaker supplying real emergency loads. I can think of very few situations that a receptacle could be supplied from an emergency generator.

In your case, as a disaster response center. I would interpet that to mean lives could be directly saved due to having power. If nothing else just to be able to comunicate. Mass text messages or emails to students. Dispatch to rescue.
I would leave the heat on the generator but not the ac. You would want to conserve fuel. Your generator should idle down when it does not have a large load. This will conserve fuel. In a disaster no body knows how long it will take to get fuel.
If you are relying on public gas. What if the disaster was an explosion that took out the utilities gas lines. You might want to consider diesel.
If you are in charge of this system also have a small standby generator.
In case the large one fails.
You did say this would be the center for disaster relief.
Click to expand...


What your suggesting violates the NEC rules.

Read the scope of 700.1 carefully then move onto 701.2 and 702.2.

If some of the loads he was supplying where true 'emergency loads' and some are not he would have to install entirely separate distribution and wiring systems for the emergency and the optional loads. It could all be supplied by one generator but that generator would have to be equipped with two output breakers, one for emergency and one for optional.


BTW you never idle an emergency generator down, that really raise heck with the frequency and makes the automatic transfer switches very uncooperative. ;)
 
BTW you never idle an emergency generator down, that really raise heck with the frequency and makes the automatic transfer switches very uncooperative.
Click to expand...

I don't know how large they come, but newer generators use inverters that allow the engine to only operate at the speed required for the load. I know Honda makes a model that does that and has a 6.5kW rating. It is part of the EU series.

I doubt that there is a 3 phase model currently available but as popularity and demand for larger, fuel efficient generators increase we may see one on the market soon.
 
K8MHZ said:
but as popularity and demand for larger, fuel efficient generators increase we may see one on the market soon.
Click to expand...

I bet your right, as many times both emergency and standby generators are grossly over sized for the average load so that they have the capacity for peak demand times.
 
What your suggesting violates the NEC rules.

Read the scope of 700.1 carefully then move onto 701.2 and 702.2.


I read it. I see your point about air handlers can be part of the fire protection system or smoke removal.
I was thinking more on the lines of a command post for a disaster.

That idle down on a generator is a nice feature.
Your right most people oversize.

In residences when some one wants a emergency generator. Lots of them want ac and hot water. Their not preparing for an emergency. Just a minor power outage.
 
buckofdurham said:
702 is intended for where life safety does not depend on the performance of the system. such as a farm or comfort.
In your case, as a disaster response center. I would interpet that to mean lives could be directly saved due to having power. If nothing else just to be able to comunicate. Mass text messages or emails to students. Dispatch to rescue.
I would leave the heat on the generator but not the ac. You would want to conserve fuel. Your generator should idle down when it does not have a large load. This will conserve fuel. In a disaster no body knows how long it will take to get fuel.
If you are relying on public gas. What if the disaster was an explosion that took out the utilities gas lines. You might want to consider diesel.
If you are in charge of this system also have a small standby generator.
In case the large one fails.
You did say this would be the center for disaster relief.
Click to expand...

the gen is diesel, the use of the area will be primarily communications, dispatching.
it may be used in the event of a disaster, but, it will not be designated as a emergency response center/.
thanks for your input.
 
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