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donf
Aug 2, 2008, 08:25 AM
Referencing question https://www.askmehelpdesk.com/electrical-lighting/how-many-houses-could-powered-11kv-244455.html

For my edification and any one else who might be interested. Are the calculations for Overhead versus lateral service planning the same? I believe that since the pots (transformers) are significantly different so would the power distribution planning.

tkrussell
Aug 2, 2008, 12:20 PM
What are you referring to? Voltage drop?

donf
Aug 2, 2008, 06:18 PM
TK,

No, I was wondering how much different Roges183's site plan would be if he went overhead versus lateral for residential or commercial Service Entry layouts.

tkrussell
Aug 2, 2008, 06:52 PM
Oh Ok. Only the conductors can be smaller in an overhead system, due to higher ampacity being in free air. The distribution equipment will be the same size/rating.

See NEC Table 310.17, I think, for free air ampacities.

The Handbook has some good info on buried conductor sizing, note the duct bank heating effect. Wire sizes get crazy.

donf
Aug 3, 2008, 05:41 AM
Thanks.