How Many Amps Is 15 kVA at 480V?

A load with an apparent power of 15 kVA at 480V draws 18.04 amps per line on a three-phase circuit. 480V is a commercial or industrial panel voltage where three-phase is the dominant interpretation. On single-phase at the same voltage the same apparent power would pull 31.25 amps. At a load power factor of 0.8 the load's real power is 12 kW (load-side conversion; a generator or UPS feeding this load has its own separate kW rating set by the manufacturer).

15 kVA equals 18.04 amps at 480 volts (three-phase, L-L)

18.04 Amps

Single Phase (480V)31.25 A

Try: 10kVA at 480V 20kVA at 480V 7.5kVA at 480V 5kVA at 480V

kVA

Volts

Amps (3Φ per line)

18.04

Assumes an AC three-phase line-to-line circuit at the input voltage. kVA is apparent power, so no power factor term is involved.

Formulas

Single Phase

I_(A) = (kVA × 1000) ÷ V

(15 × 1000) ÷ 480 = 15,000 ÷ 480 = 31.25 A

Three Phase (480V Line-to-Line)

I_(A) = (kVA × 1000) ÷ (V_L-L × √3)

15,000 ÷ (480 × 1.732) = 15,000 ÷ 831.36 = 18.04 A

Applies to 480Y/277 or 480 delta systems where 480V is the line-to-line voltage.

Single Phase vs Three Phase

The same 15 kVA unit draws very different current depending on the phase configuration:

Configuration	Formula	Current at 480V
Single Phase	15,000 ÷ 480	31.25 A
Three Phase (480V L-L)	15,000 ÷ (480 × √3)	18.04 A

For this specific case, 15 kVA at 480V, three-phase carries about 42.26% less current per line than single-phase at the same voltage. That gap tracks the 1 ÷ √3 factor for L-L three-phase (or 1 ÷ 3 for L-N), which is why three-phase distribution is common at commercial and industrial scale: the same apparent power rides on smaller conductors and smaller breakers (applies to 480Y/277 or 480 delta systems).

Generator & UPS Sizing

Load-Side Real Power by Power Factor

A load with an apparent power of 15 kVA draws different amounts of real power depending on the load's own power factor. The table below is a load-side conversion, not a forecast of what a generator or UPS will output for that load: generators and UPS units publish their own independent kW rating set by the engine or inverter design, and that rating is often lower than kVA × the load's PF.

Load Type	Load PF	Load Real Power (kW)	Current at 480V (three-phase, per line)
Resistive (heaters, lights)	1.0	15 kW	18.04 A per line
Mixed typical	0.85	12.75 kW	18.04 A per line
Motors/HVAC	0.80	12 kW	18.04 A per line
Computers/servers (no PFC)	0.65	9.75 kW	18.04 A per line

Note: current draw stays the same across the rows because kVA sets the current, not the load's power factor. PF only affects how much real work (kW) the load does per amp drawn.

Sizing a load against a source. If you are feeding this load from a UPS, generator, or transformer, check the load against both the source's kVA rating AND the source's kW rating. Those are two independent numbers published by the manufacturer. A 10 kVA / 8 kW generator, for example, can supply up to 10 kVA of apparent power AND up to 8 kW of real power, whichever limit is reached first. Do not use the kW figures above as a substitute for the source's published kW rating.

Circuit Sizing: Starting Points

The numbers below are rough order-of-magnitude starting points under typical assumptions (copper conductors, 75°C terminations, short run, no ambient or bundling derates, non-continuous duty). They are not install specs. Actual breaker and wire selection depends on the equipment nameplate, conductor and termination temperature ratings, cable type, run length and voltage-drop target, ambient and bundling conditions, whether the load is continuous, any NEC 430/440 motor or HVAC provisions, and local code.

	Single Phase	Three Phase
Current draw (at full kVA)	31.25 A	18.04 A
Ballpark branch OCP	~35A	~20A

For a real install, run the full wire-size calculator with your actual run length, voltage, and drop target, and verify breaker selection against the equipment nameplate and local code.

Energy Cost at Full Load

A load with an apparent power of 15 kVA at load PF 0.85 draws 12.75 kW of real power. Running cost at that draw: $2.17/hour at $0.17/kWh (rates last reviewed April 2026), or $520.20/month (8h/day). Full breakdown.

kW Equivalent

15 kVA at PF 0.85 = 12.75 kW. See 12.75 kW to amps at 480V.

Other kVA Ratings at 480V

kVA	Three Phase Amps (L-L, per line)	Single Phase Amps	Real Power (PF 0.8)
1 kVA	1.2 A	2.08 A	0.8 kW
2 kVA	2.41 A	4.17 A	1.6 kW
3 kVA	3.61 A	6.25 A	2.4 kW
5 kVA	6.01 A	10.42 A	4 kW
7.5 kVA	9.02 A	15.63 A	6 kW
10 kVA	12.03 A	20.83 A	8 kW
15 kVA	18.04 A	31.25 A	12 kW
20 kVA	24.06 A	41.67 A	16 kW
25 kVA	30.07 A	52.08 A	20 kW
30 kVA	36.08 A	62.5 A	24 kW
40 kVA	48.11 A	83.33 A	32 kW
50 kVA	60.14 A	104.17 A	40 kW

Frequently Asked Questions

How many amps is 15 kVA at 480V?expand_more

15 kVA at 480V is 18.04 amps per line on a three-phase circuit (480Y/277 or 480 delta), or 31.25 amps on single-phase at the same voltage.

What size breaker would I need for 15 kVA at 480V?expand_more

This is a sizing question, not a conversion question, and there is no single answer from a page like this. Breaker selection depends on the equipment nameplate FLA, whether the load is continuous (NEC 210.19(A) applies the 125% continuous-load rule), conductor ampacity and termination temperature, any NEC 430/440 motor or HVAC provisions, and local code. The current draw on this page is the input to that sizing process, not the output. Verify against the equipment nameplate and a licensed electrician.

What is the difference between kVA and kW?expand_more

kVA is apparent power (V×I), which sets the current on the circuit and the sizing of conductors, breakers, and windings. kW is real power (the portion that does useful work), equal to kVA×load PF. A load with an apparent power of 15 kVA at load PF 0.8 draws 12 kW of real power. For a source such as a generator or UPS, kVA and kW are two independent manufacturer ratings, not two views of the same spec, and both have to be checked when sizing a load.

How much fuel does a 15 kVA generator use?expand_more

Fuel burn is set by the generator's specific-fuel-consumption curve, not a rule of thumb tied to the kVA rating. It varies sharply with fuel type (gasoline vs diesel vs natural gas vs propane), load percentage (partial-load efficiency is much worse than full-load), engine size and age, altitude, and ambient temperature. For a specific unit, check the manufacturer's fuel-consumption curve at your expected load percentage. Generic per-hour estimates from the kVA rating alone are not reliable enough to plan fuel capacity from.

Three-phase vs single-phase for 15 kVA?expand_more

Three-phase (480Y/277 or 480 delta) draws 18.04A per line. Single-phase at the same voltage draws 31.25A. Three-phase delivers the same apparent power across three conductors, so each line carries less current and the wire and breakers can be smaller for the same kVA.

This calculator provides estimates for reference purposes only. Always consult a licensed electrician and verify compliance with the National Electrical Code (NEC) and local electrical codes before performing any electrical work.