In older RVs that run off 30 amp main power, you may find a switch like behind your sink cabinet door (among other places). Essentially it keeps you from running two fairly high-amp appliances at the same time. If you were to turn on your water heater and your microwave at the same time you would probably trigger a circuit breaker. They are both on the same 20A breaker and cannot be run simultaneously.
Please note that this does not count when you are using propane heated water. If your hot water tank can be heated electrically as well as by gas, you can heat water by gas while using your microwave. Just keep the switch in the microwave position. Further, the most common place to find where to ignite your water tank is a switch on your range hood.
2 comments
Thx John! How do you know if you are using electric or gas on the water heater? Is there a switch for that?
If you turn off the “Water Heater” switch here and then turn on the “Heater” switch on your oven hood (it’s a very small switch), you should hear a “swooooosssshhhh” as the pilot ignites the gas to begin heating the water. I believe if you have the electric on the pilot won’t do anything and the gas will shut off. I’ll try to get a photo of my hood switch when I have a chance.