Emergency Power Generation

[bonding jumper]

I have to design an emergency power generator for an existing building. The generator is to serve general lighting, Fire alarm, some computers, and boiler room and pumps. Previously I have only done Generator installations to supply fire pumps, and in these applications, the NEC requires MI (Mineral Insulated) cables from the generator to the fire pump. In my application where my generator is not feeding any life saving devices (Firepump) am I still required to use MI cable? Is the feed from the Generator treated as another Service? Is that why I must use a fire rated MI cable? because of the fear of that cable burning up? Any help is appreciated. Thanks in advance.

 

[caj1962]

Re: Emergency Power Generation

where in the code does it say that you must use MI cable?
In article 700 it gives you several options for feeders(1) Feeder-Circuit Wiring. Feeder-circuit wiring shall meet one of the following conditions:
(1) Be installed with buildings that are fully protected by an approved automatic fire suppression system
(2) Be a listed electrical circuit protective system with a minimum 1-hour fire rating
(3) Be protected by a listed thermal barrier system for electrical system components
(4) Be protected by a fire-rated assembly listed to achieve a minimum fire rating of 1 hour
(5) Be embedded in not less than 50 mm (2 in.) of concrete
(6) Be a cable listed to maintain circuit integrity for not less than 1 hour when installed in accordance with the listing requirements
(2) Feeder-Circuit Equipment. Equipment for feeder circuits (including transfer switches, transformers, and panelboards) shall be located either in spaces fully protected by approved automatic fire suppression systems (including sprinklers, carbon dioxide systems) or in spaces with a 1-hour fire resistance rating.

You may aslo want to check in NFPA 110 also for more requirements for the specfic application you are undertaking.

 

[tim robben]

Re: Emergency Power Generation

If the generator does not serve any Life Safety loads then DO NOT refer to it as "Emergency" standby generator. It is an "Optional" standby generator. The difference is significant and when you refer to the generator on plans and specificiations as "Emergency" the plan reviewer may apply the requirements of Article 700 or 701. If you have battery powered egress and exit lighting and the Fire Alarm panel has battery backup power, and there are no other Life Safety loads that have the generator as the only backup power then it is a "Optional" standby generator.

Somehow I have gotten around having to design a power system for a fire pump. But after a quick review of Article 695 I see where the MI wire is required. In an "Otional" standby generator MI wire is not required... as far as I can tell.

 

[caj1962]

Re: Emergency Power Generation

Tim
I just read all of 695 and do not see where Mi cable is the only type of wiring required. There are several methods listed in 695 and if you read article 700 one the wiring methods mentioned there state if the building has a fire suppression system then you can used other regonized wiring methods. The title of this post is about a fire pump so I am assuming that the building will have a fire suppression sytem in it.IMO 700 sets up the rules for all gen sets and then 701 and 702 get specific about about what type of emergency system you are going to have.

 

[don_resqcapt19]

Re: Emergency Power Generation

Cal,
700, 701 and 702 apply to different types of systems. 700 applies to legally required life safety systems, 701 to legally required standby systems that do not serve life safety circuits and 702 is a systems that is not required by law. The rules in 700 do not apply to 701 or 702.
Don

 

[iwire]

Re: Emergency Power Generation

Originally posted by bonding jumper:
I have to design an emergency power generator for an existing building. The generator is to serve general lighting, Fire alarm, some computers, and boiler room and pumps.

What I notice is your mention of "general lighting".

Is this general lighting optional lighting or will it serve as the emergency lighting.

If the answer to that is yes the job just got more complicated.

If you do have both article 700 loads and either, or both 701 and 702 loads you will need at least two breakers on the generator and separate ATSs and distribution to keep the 700 loads separate from the 701 and or 702 loads. 700.9(B)

[ October 21, 2003, 06:18 PM: Message edited by: iwire ]