Emergency generator

[hhsting]

Attached i have emergency generator in high rise building.

The emergency generator has two main breaker one 150A which goes to fire pump 480V three phase and another 600A which goes to distribution Panel Gen

Panel Gen demand load is 120.28A at 480V three phase and 100kVA.

The emergency generator total demand load including fire pump and Gen is 292.71A at 480/277V three phase and demand of 243.5kvA.

Generator capacity is 400kw at 480V three phase is 481.13A.

The emergency generator at present has enough capacity. One can add in future and i think emergency generator maybe undersized for that. So the breaker 150A + 600A = 750A would be the total load while generator demand capacity is 481Ax1.25=601A.

Questions:

1. Would the generator capacity be full load amps of the generator or generator FLAx1.25?

2. Is their anything in the NEC 2017 that address future loads of the generator capacity must also be enough to support its load when sizing emergency generator? I know load shedding but can that be also for future and can be enforced now Not in future?


3. Panel Gen total demand load is 120.28A while the breaker provided is 600A? Is there anything in NEC 2017 that limits the size of emergency breaker?

4. Optional loads demand loads are 133A yet breaker provided is 200A. Is this breaker sized correct? Is there anything in NEC 2017 which says how to size that breaker?

5. Life and safety total loads are 131.9A but breaker provided is 225A. Is this breaker size correct? Is their anything in NEC 2017 which says how to size the breaker?

 

[tom baker]

You are asking us to engineer this system and the generator question is two other posts. Some of your questions should be directed to the plan submitter. If the submitter is a EE, isn’t the EE responsible, make notes on your plan review saying ensure generator breaker is adequate for fire pump starting

 

[hhsting]

You are asking us to engineer this system and the generator question is two other posts. Some of your questions should be directed to the plan submitter. If the submitter is a EE, isn’t the EE responsible, make notes on your plan review saying ensure generator breaker is adequate for fire pump starting

Right now the demand is less than emergency gen capcity but due to breaker provided in Future can exceed. How? Can that be enforceable?

Its not about fire pump only its about the entire emergency which powers the optional, life safety (non fire pump load) and legally required
This post is also about sizing breakers. Please see post #1

 

[tom baker]

You are asking about 4 different breakers. Ask the submitter those questions, not us.

 

[hhsting]

You are asking about 4 different breakers. Ask the submitter those questions, not us.

I am trying to figure out what code I can enforce in NEC 2017 to the designer. Please help me out

The designer has 225A feeder and 400A feeder. According NEC 2017 section 215.2(A)(1) conductors are Not less than load calcs of 220.

However in future the emergency generator can have problems and can be undersized.
700.4 does Not say anything about future

Please help me out i am trying to find code section on this

 

[tom baker]

Look in chapter 90

 

[augie47]

Your answer is shown in Post #2 and #4. If you are doing plans review and you show a calculated load that is about half of the generator capacity.
you don't find any Code reference that addresses "future" or "what if" load as there is no such Section.; in fact, as tom points out, it pretty much states the opposite in 90.1 "....not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.
On this thread (and the fire pump breaker thread) your concern may be warranted but the best you can do, until you start engineering drawings, is to question the engineer/designer. It would behoove you to document your concern and then let the drawings dictate the installation

 

[tom baker]

I very much agree with last sentence.

 

[hhsting]

About the generator capcity posf #1 is the FLA the generator capacity or 1.25% of FLA generator capcity?

 

[roger]

About the generator capcity posf #1 is the FLA the generator capacity or 1.25% of FLA generator capcity?

A word to the wise, there is enormous liability in changing or forcing a change to an EE's emergency system design. If something did happen your documented comments leading to the change will be front and center in lawsuits.

Roger

 

[hhsting]

I am no longer trying to change his design regarding panel GEN breaker size. I also get it gen capacity in future can be undersized but thats in future no problem nothing can be dome about future stuff.

I guess i should start separate thread about emergency generator main breaker sizes its self 150A and 600A when compared to generator size compared 400kW generator at 480V three phase. Oversize or undersize