Originally Posted by actadh
I have a Soleus brand 400/800 watt flat panel tower radiant heater with swivel.
It was hard to find one that went down to 400 watt. Amps on low: 3.3. Amps on high: 6.7.
Most circuits inside the RV are going to be controlled by a 15 amp circuit breaker.
If you know the wattage of a heater (hair dryer, microwave, etc), it's real easy to configure the amps.
Watts = volts X amps.... or watts/divided by volts = amps
Using actadh's heaters example above, you can see that 400 watts/divided by 120 volts = 3.33 amps or rounded to 3.3
800 watts/divided by 120 volts = 6.66 amps or rounded to 6.7 amps.
It's good for RV'ers to know this formula to keep from overloading circuits (which includes the amperage of all 120 volt items on that same circuit).
Just for an example, a 1500 watt heater on 120 volts uses 12.5 amps and an 1800 watt one uses 15 amps..... so you can see how space heaters (and hair dryers) can require some high amps.
You just have to practice energy management sometimes and figure out what amps your appliance needs vs what your circuit has the capability of. Even with a 15 amp circuit breaker, that doesn't mean you should use 15 amps of appliances constantly.... which still may cause the breaker to trip.