What to check before ordering
4160 V is a medium voltage class below the usual utility primary, so these are frequently customer owned rather than utility owned, which changes who buys the transformer and who maintains it.
Current at each rating
Three phase full load current on both sides of a 4160 V to 480Y/277 V transformer. The higher voltage side always carries less current for the same kVA.
| kVA | 4160 V side | 480Y/277 V side |
|---|---|---|
| 15 | 2.1 A | 18.0 A |
| 30 | 4.2 A | 36.1 A |
| 45 | 6.2 A | 54.1 A |
| 75 | 10.4 A | 90.2 A |
| 112.5 | 15.6 A | 135 A |
| 150 | 20.8 A | 180 A |
| 225 | 31.2 A | 271 A |
| 300 | 41.6 A | 361 A |
| 500 | 69.4 A | 601 A |
Nameplate full load current, computed from the standard three phase formula. Free to cite with a link to this page. For any rating not listed, use the kVA to amps calculator.
Common questions
What transformer do I need to go from 4160 V to 480Y/277 V
A step down transformer with a 8.7 to 1 ratio. Industrial plants and older campuses that distribute internally at 4160 V, plus some municipal systems that never moved up to 12.47 kV. Most units for this conversion fall in the 75 to 2500 kVA range.
How many amps does a 4160 V to 480Y/277 V transformer draw
It depends on the kVA. At 100 kVA the 4160 V side carries about 13.9 amps and the 480Y/277 V side about 120 amps. Current is kVA times 1000 divided by the voltage times the square root of three, so the higher voltage side always carries less current for the same kVA.
What should I check before ordering
4160 V is a medium voltage class below the usual utility primary, so these are frequently customer owned rather than utility owned, which changes who buys the transformer and who maintains it.