The ASHRAE requirement (Prerequisite for LEED) limits voltage drop in feeders to 2% based on demand. So while the ampacity of the cables is well below the allowable maximum, voltage drop becomes the limiting factor in high-rise buildings. The NEC limits the feeders to 3% voltage drop (5% overall).
Can anyone comment on the counter-productive nature of this requirement for cities like New York? The larger feeder sizes in high-rise buildings becomes costly for owners and takes up more space. How is this an energy saving measure?
Ante Vulin
Sustainability ManagerYR&G
80 thumbs up
July 19, 2012 - 9:17 am
Amanda, apologies that this is so late but for anyone else searching "feeders," please note recent interpretation #10218 dated 7/1/2012 which states that "the mandatory provision of ASHRAE 90.1-2007/2010 Section 8.4 will be met as long as the total voltage drop does not exceed 5%." The total voltage drop is defined over "from service entrance to the worst-case connection"
Giorgia Lorenzi
Engineer LEED APStrategie d'Impresa
July 19, 2012 - 9:57 am
Ante where can I find this interpretation? I looked for in the interpretation section of ASHRAE website but I've not found it. Thank you. Giorgia
Ante Vulin
Sustainability ManagerYR&G
80 thumbs up
July 19, 2012 - 11:43 am
Giorgia, this a LEED interpretation, which you can find by going to https://www.usgbc.org/leedinterpretations/lilanding.aspx and searching for "10218"