How many amps are generated by a 1500 watt heater at 208 volts?

Answer 1

You have to be careful here. A heater will be advertised as "X" watts, but that is only true if you connect it to the voltage source it is supposed to be connected to. If you plug it into a higher or lower voltage source than intended, it will produce a different number of watts.

Electric heaters are just resistors. When you run electricity through them, they get hot. If you run more electricity through that resistor, it will produce more heat. If you run less electricity through it, it will produce less heat.

As an example, you can find "1500W/120V" water heater elements at the hardware store. This means that if you plug it into a 120V source, it will produce 1500W of heat, and it will pull 1500W/120V = 12.5A of current.

You can calculate the resistance of the heater by taking voltage times voltage divided by watts, so this "1500W/120V" heater is really just a resistor of this many Ohms:

120V * 120V / 1500W = 9.6 Ohm

That Ohm value is physical property of the device. It will not change. If you were to take this heater now and plug it into a 240V supply, you can calculate the amps with voltage divided by resistance:

240V / 9.6 Ohm = 25 Amps

And, for watts, you can take voltage times voltage divided by ohms:

240V * 240V / 9.6 Ohm = 6000W

Sorry for the long text, but it's crucial that you understand this.

If your heater is 1500W and is INTENDED to be running on 240V, you have a 38.4 Ohm resistor. Running that resistor at the lower 208V will produce only 1126W of heat and will pull just 5.4 Amps of current.

However, if your heater is 1500W and is indented to be running on 120V, then you have a 9.6 Ohm resistor. You will almost certainly start a fire if you plug it into a 208V supply, because you will be pulling close to 22 Amps and producing 4500W of heat.

Answer 2

7.2