RV Air Conditioner Amps Calculator
15,000 BTU RV air conditioner draws about 15.00 amps at 120V while running.
RV Air Conditioner Amps Explained
RV air conditioners run on 120V AC, typically supplied by 30A or 50A shore power, an onboard generator, or an inverter. A common 15,000 BTU RV rooftop AC unit draws roughly 1800W while running, which is 15.00 amps at 120V. That is half of a 30A shore power connection, which is why running an RV AC alongside a microwave or water heater on the same 30A service commonly trips the breaker. Startup surge current can briefly spike to 2-3x the running amps, which is why many RVers add a soft-start capacitor to their AC unit.
Frequently Asked Questions
How do I convert watts to amps?
For DC circuits, divide watts by volts (Amps = Watts ÷ Volts). For AC single-phase circuits, divide watts by the product of power factor and volts. For AC three-phase circuits, divide watts by the product of √3, power factor, and volts.
Why do I need power factor for AC calculations?
Power factor accounts for the phase difference between voltage and current caused by inductive loads like motors and compressors. Purely resistive loads (heaters, incandescent bulbs) have a power factor of 1.0. Motors typically run 0.8–0.95.
What breaker size do I need for a 1500W appliance at 120V?
1500W at 120V draws 12.50 amps. Per NEC Article 210.20, continuous loads must not exceed 80% of a breaker rated capacity, so a 15A breaker (12A max continuous) is not sufficient. A dedicated 20A circuit is required.
Does this calculator work for 240V appliances?
Yes. Enter your wattage and set voltage to 240V for dryers, water heaters, ranges, and EV chargers. At the same wattage, 240V circuits draw half the current of 120V circuits.
Is this calculator accurate for 3-phase industrial power?
Yes. Select the AC 3-Phase tab, enter your line voltage (commonly 208V or 480V), and choose line-to-line or line-to-neutral mode. The calculator uses the precise value of √3, not a rounded 1.732 approximation.
Can I use this to size wire gauge?
The calculator provides an AWG wire gauge recommendation based on NEC Table 310.15(B)(16) for 60°C copper conductors. Always confirm final wire and breaker sizing with a licensed electrician before installation.