Both work just as well. The only difference is what the supply voltage is at hand. Heaters are rated in watts. Your electric bill is rated in watts consumed per hour. Watts = Amps x Volts. An example, 500 watt heater at 120 volts will equal 4.16 amps. The same heater at 240 volts will equal 2.08 amps. As you can see if the voltage goes up the current goes down but the wattage total is always the same. That is the reason that you are billed on wattage, and not on what the service voltage or the current draw of the service is.
20 amp is perfect, 15 is fine
Yes, the heater is a 240/120 heater, but I want to operate as 120 volt
15 amp
If it does not come with a plug on it, no. If it is made for direct wire, then 99.9% chance is that it is a 240 volt unit. If you plug it into a 120 volt outlet your water will barely get warm.
If V is the rated voltage of the equipment, and Vs is voltage of the supply, we have this approximate equation: Vs = 2 V. That is enough to wreck the equipment and/or blow the fuse.120 volt appliance on 240 voltsThis senerio will use an electric baseboard heater but the results will be the same for any electrical appliance.The heater will operate over its given specified wattage. A 120 volt heater run off of 240 volt will have an output increase. Ohms law stated that current is directly proportional to the applied voltage and inversely proportional to the resistance of the circuit. A 240 volt heater can be run off of 120 volts but the wattage will be reduced.For example if an ordinary 1000 watt baseboard heater's supply is 120 volts, the current of the heater will be, I = W/E 1000/120 = 8.3 amps.The resistance of the heater is R = W/I (squared) =1000/8.3 x 8.3 (69) = 14.5 ohms.Applying 240 volts on the same heater whose resistance is 14.5 ohms results in a new heater wattage rating. W = E (squared)/R = 240 x 240 (57600)/14.5 = 3972 watts.This is 2972 watts, almost 300%, higher than the manufacturer's designed safety rating.The amperage drawn by connecting a 120 volt, 1000 watt heater to a 240 volt source will be, I = W/E = 3972/120 = 33 amps.W = watts, I = amperage, R = resistance in ohms and E = voltage.
No. A water heater requires a 240 volt connection and cannot be re-wired to run on 120 volts. There isn't enough amperage in 120 volts to power the heating rods that are inside.
20 amp is perfect, 15 is fine
Yes, the heater is a 240/120 heater, but I want to operate as 120 volt
15 amp
If it does not come with a plug on it, no. If it is made for direct wire, then 99.9% chance is that it is a 240 volt unit. If you plug it into a 120 volt outlet your water will barely get warm.
If V is the rated voltage of the equipment, and Vs is voltage of the supply, we have this approximate equation: Vs = 2 V. That is enough to wreck the equipment and/or blow the fuse.120 volt appliance on 240 voltsThis senerio will use an electric baseboard heater but the results will be the same for any electrical appliance.The heater will operate over its given specified wattage. A 120 volt heater run off of 240 volt will have an output increase. Ohms law stated that current is directly proportional to the applied voltage and inversely proportional to the resistance of the circuit. A 240 volt heater can be run off of 120 volts but the wattage will be reduced.For example if an ordinary 1000 watt baseboard heater's supply is 120 volts, the current of the heater will be, I = W/E 1000/120 = 8.3 amps.The resistance of the heater is R = W/I (squared) =1000/8.3 x 8.3 (69) = 14.5 ohms.Applying 240 volts on the same heater whose resistance is 14.5 ohms results in a new heater wattage rating. W = E (squared)/R = 240 x 240 (57600)/14.5 = 3972 watts.This is 2972 watts, almost 300%, higher than the manufacturer's designed safety rating.The amperage drawn by connecting a 120 volt, 1000 watt heater to a 240 volt source will be, I = W/E = 3972/120 = 33 amps.W = watts, I = amperage, R = resistance in ohms and E = voltage.
I don’t know
Yes, but by using 120 volts on the 208 volt element you will only be able to obtain 1/4 of the rated wattage from the element not 1/2 like it seems you should.
First find the current, I = W/E, 450/120 = 3.75 amps. R = E/I, 120/3.75 = 32 ohms.
You don't. The heater will operate over its given specified wattage. A 120 volt heater run off of 240 volt will have an output increase. Ohms law stated that current is directly proportional to the applied voltage and inversely proportional to the resistance of the circuit. A 240 volt heater can be run off of 120 volts but the wattage will be reduced. For example if an ordinary 1000 watt baseboard heater's supply is 120 volts, the current of the heater will be, I = W/E 1000/120 = 8.3 amps. The resistance of the heater is R = W/I (squared) =1000/8.3 x 8.3 (69) = 14.5 ohms. Applying 240 volts on the same heater whose resistance is 14.5 ohms results in a new heater wattage rating. W = E (squared)/R = 240 x 240 (57600)/14.5 = 3972 watts. This is 2972 watts, almost 300%, higher than the manufacturer's designed safety rating. The amperage drawn by connecting a 120 volt, 1000 watt heater to a 240 volt source will be, I = W/E = 3972/120 = 33 amps. W = watts, I = amperage, R = resistance in ohms and E = voltage.
From a 120 Volt supply, the Amp rating is calculated as 2,000 Watts (which is 2kW) divided by 120 Volts = 16.7 Amps.
I recommend 120 volt 20 watt halogen if you are on a budget. If you can afford them 120 volt LED is even better and will last for years.