Feeder Selection
Feeder Selection
(OP)
In selecting the proper size feeder to a transformer, should I consider the type of load the transformer feeds or should I just go by the primary current required? I am curious if one ever considers that the load may or may not be continuos or non-continous. I have a 3-Ph, 480V-208/277V, 45 kVA, general usage for lighting,hand tools amd other miscellaneous small loads - no motors. Thank you for your info.






RE: Feeder Selection
Mike
RE: Feeder Selection
1- Ampacity
2- Voltage drop.
3- Short circuit withstands.
For LV, ampacity and voltage drop may be the main factor in most cases.
In absence of known detail information of the load (presently and future) most people select the feeder ampacity base on the transformer size and a conservative power factor.
RE: Feeder Selection
Your last comment was precisely what I was thinking. Since our intended load varies by the tasks at hand, my preference was to go with the primary current required by the Xfmr in selecting the feeder size. Additionally, I was trying to adhere as close as I could with NEC 215.2, even though there cold be some diversity factors that could be considered, practically speaking.