Service Question

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bphgravity

Senior Member
Location
Florida
I finally received the revision for this project. Now the plans show TWO serivce laterals from the transformer to the indoor equipment room. Each consist of 350 kcmil conductors terminating at the TWO 400A main enclosures. Agian the calculated load at each 400A panel is around 250A.

It appears 230.2 / 230.40 Exception No. 2 permits the two laterals and two service entrance conductors, however I am not sure 230.90(A) or Exception No. 3 ?

What say you?
 
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Jomaul

Senior Member
Location
Ocala, Fl
I agree with you on 230-90 (A) , you can't get around that article , on exception 3 my opionion is that that exception is talking abount going to the next higher standard circuit breaker or a service to a motor control panel where the overcurrent protection is greater than the conductor size.
 
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Jomaul

Senior Member
Location
Ocala, Fl
I think they can do this as per article 230.2. from the post they clearly met the requirements of this article. By this article its only 1 service
 
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bphgravity

Senior Member
Location
Florida
I am not sure where the service point is. There is nothing on plan indicating who owns the service lateral conductors.

Per the definition in Article 100, the service laterals become service entrance conductors where they enter the building from underground. 230.2 indicates this could be viewed as ONE service, but like indicated by Ryan, can this structure be supplied bt TWO laterals?

Do we all agree that the service overcurrent devices need to be reduced or the service conductors sizes increased to match each other?
 
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Jomaul

Senior Member
Location
Ocala, Fl
I would think that these conductors would be considered service entrance conductors and the transfomer terminals would be the service lateral . yes either reduce the ocp or increase the conductor size
 
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RB1

Senior Member
I agree that the service conductors need to be increased in size, or the rating of the service disconnecting means needs to be decreased, in order to comply with 230.90(A).

230.90(A) Exception No. 3 applies only to conductors supplying more than one service disconnecting means, even then, none of the two to six disconnecting means are permitted to exceed the rating of the service conductors except as permitted by the other exceptions to 230.90(A).

I think there is one service supplying the building no matter who owns the service conductors per 230.2.
 
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frenchelectrican

Senior Member
Location
Nord'est Wisconsin et Paris France
bphgravity said:
I finally received the revision for this project. Now the plans show TWO serivce laterals from the transformer to the indoor equipment room. Each consist of 350 kcmil conductors terminating at the TWO 400A main enclosures. Agian the calculated load at each 400A panel is around 250A.

It appears 230.2 / 230.40 Exception No. 2 permits the two laterals and two service entrance conductors, however I am not sure 230.90(A) or Exception No. 3 ?

What say you?
Click to expand...

Tell ya the truth for a sec,.. just stop and think for a sec if this on commercal area the 350's is little small for me for 400 amp service but i did see you have calculated load at 250amps. that ok for that size but what if down the road if they add more stuff and get the 350 KCM conductors overloaded based on the 75degree termation i rather run it with 500KCM conductors [ of course in copper ]

and IMO for most commercal area i useally sized the cable to the OCPD unless you are playing at magic " 800 " number that will get little tricky that is a fine line i have to thread carefully there


Merci, Marc
 
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