Transformer Selection & Sizing
1000 kVA Transformer Amps and Breaker Size (480V–4160V)
A 1000 kVA transformer carries 1,203 amps at 480 volts three phase and 138.8 amps at 4,160, because amps are 1,000,000 divided…
Transformer Selection & Sizing
500 kVA Transformer Amps: Full-Load Current by Voltage
A 500 kVA transformer carries 601 amps at 480 volts three phase, 1,203 amps at 240, 1,388 amps at 208 and 20.9…
Transformer Selection & Sizing
How to Calculate Transformer Primary and Secondary Current
Three phase current is kVA times 1,000 divided by 1.732 times line voltage. Single phase leaves the 1.732 out. That is the…
Transformer Selection & Sizing
NEC 450.3 Transformer Protection: A Practical Walk-Through
Article 450.3 caps the device, not the wire. At 1,000 volts or less, take 125 percent of primary full load current and…