Service Entrance Conductor OCP

[pwest]

I am currently on a project in which the specified 2000Amp, 3PH, 480V main switch is to be fed with 4 sets of 500MCM (CU) from the utility co. transformer. Assuming the calculated loads (1500Amps) are in accordinance with Article 220 and 230.42. The 4 sets of 500MCM are only good for 1520Amps at 75c. My question is, does Article 230.90 or any other article apply to the over current protection of these service entrance conductors? We are being asked to proceed as specified although this does not seem like a good idea. In the event of an added piece of equipment the service entrance conductors have the potential to draw more than 1520Amps without tripping the 2000A switch

[ January 10, 2006, 10:42 AM: Message edited by: pwest ]

 

[don_resqcapt19]

Re: Service Entrance Conductor OCP

230.90(A) applies and you can't use that cable on a single 2000A OCPD. If there is more than one service disconnect, then Exception 3 applies and the service cable only has to be sized for the calculated load.
Don