dinkelja
Electrical
- Dec 10, 2004
- 31
Any advice / opinions for a young engineer - would be helpfull. I am working with a designer on sizing feeders to a freezer / cooler room. The PDP requires a 3000A service (480v, 3ph, 4w), but has 75deg C terminations. The designer wants to run 10 sets of 500kcmil in seperate RMC. The run is 250'. (I wonder what that comes down to per foot, $30, anyways)? I don't know if that is relitevely short way for an electrician to pull that much cable; it is about 2 bends plus the rise and drop, I called out 4"C. I am looking at the NEC tables and this seems reasonable, but in practicality, how would any of you do it? The combined ampacity would then be 3800A. I am also having trouble finding the NEC article on grounding with multiple conductors 250-?. He says 1250 kcmil in a seperate conduit. This is all copper wire by the way. I haven't addressed the 1 hour fire rating yet, supposedly the coolers need to stay running through the fires of he** and back. I need to get to reading that code quickly. (we are having a disagreement about feeders for fire pumps as well) thanks, Jared - Cincinnati, Ohio, USA