Mike Dolt Enterprises
Mike Dolt Enterprises
User: DARUSA, Location: New York City
Asked on: Thursday, March 17, 2011 at 9:00 am EDT
Answered on: Tuesday, May 14, 2024 at 2:55 am EDT
Question: Hi to all.Have a situation were we run the service feeder wire.He have a Man-hole inside of the property were we run the service feeder from our switch gear.We own the boxe and the feeder,1600 amp service .We did run 4 set of 600 Kcmil thwn-2 wire. When Con-ned representative come to check it ,he require that the wire th have to be a RHW wire.That is a 2 hrs fire rate wire!!! We explain the guy that ,it is not a nec requirement! As long our wire is rated for wet location we fine!!!Now after that he says that we can't use 600 wire because it is not aprove by CON-ED , we have to use 5 sets of 500 wire to connect to the crab.600 is rated for 420 amp why is this wrong?Have you guys any experience on it?
NEC Requirements
The National Electrical Code (NEC) does not specifically require RHW (resistant to heat and water) wire for service feeder installations. However, it does require that the wire be suitable for the location and operating conditions.
Con Edison (Con Ed) Requirements
Con Ed, as the local utility, may have additional requirements for service feeder installations in its jurisdiction. These requirements may include using RHW wire.
Ampacity of 600 Kcmil THWN-2 Wire
As you mentioned, 600 Kcmil THWN-2 wire is rated for 420 amps according to the NEC. However, Con Ed may have its own calculations or standards that take into account specific factors in its service area, such as voltage drop and thermal dissipation.
Use of 5 Sets of 500 Kcmil Wire
Using 5 sets of 500 Kcmil wire would provide a total ampacity of 1000 amps, which is higher than the 840 amps provided by 4 sets of 600 Kcmil wire. This may be necessary to meet Con Ed's specific requirements or to provide additional capacity for future expansion.
Recommendations: Review Con Ed's specific requirements for service feeder installations in your jurisdiction. Contact Con Ed directly to verify if 600 Kcmil THWN-2 wire is acceptable for your installation. If Con Ed requires RHW wire, use wire that meets that specification. If Con Ed requires 5 sets of 500 Kcmil wire, use wire that meets that specification.* Document all communication with Con Ed and their requirements in writing for future reference. Flag for review