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SteamWake · 09-23-10, 08:22 AM

American distribution is like this

All 60 Hz

(Common) Transmission lines 1,2470V 3 phase

Stepped down to 277/480 (3 phase) often for commercial buildings lighting and equipment.

Then stepped down again to 120/240V (single phase common for homes and smaller facilites) or 120/208V (3 phase common for commercial buildings receptacles and light equipment.

Very rarely is 12470 brought into a building but it is not unheard of. Also 4,000V is sometimes used for large commercial facilitys (Sawmills, Hospitals, etc.)

Oh and its the square root of 3 for three phase but thats only for calculating current. It is still commonly refered to 208V 3 Phase but the calculation for current is (wattage) / (voltage x square root of 3)=I or current.

I commonly will just round off the numbers for quick calculations. 480V = 831, 208V = 360

09-23-10, 08:22 AM	#38
SteamWake Rear Admiral Join Date: Mar 2005 Posts: 13,224 Downloads: 5 Uploads: 0	American distribution is like this All 60 Hz (Common) Transmission lines 1,2470V 3 phase Stepped down to 277/480 (3 phase) often for commercial buildings lighting and equipment. Then stepped down again to 120/240V (single phase common for homes and smaller facilites) or 120/208V (3 phase common for commercial buildings receptacles and light equipment. Very rarely is 12470 brought into a building but it is not unheard of. Also 4,000V is sometimes used for large commercial facilitys (Sawmills, Hospitals, etc.) Oh and its the square root of 3 for three phase but thats only for calculating current. It is still commonly refered to 208V 3 Phase but the calculation for current is (wattage) / (voltage x square root of 3)=I or current. I commonly will just round off the numbers for quick calculations. 480V = 831, 208V = 360 __________________ Follow the progress of Mr. Mulligan : http://www.subsim.com/radioroom/showthread.php?t=147648