Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. Today he discusses plugging a trailer into a house’s electricity, and keeping tanks from freezing.
Dear Dave,
Can I plug electricity from my house into the travel trailer with no problem? And how can I keep the water tanks from freezing? —Miguel
Dear Miguel,
I get this question in my seminars quite often. The answer is not a simple one since you need to know the power requirements of your rig and what you are plugging into.
Plugging in at the house
First, let’s look at what you are going to plug into at your house. I see a lot of people bring their rig to the driveway and plug a “heavy-duty” extension cord into a receptacle inside the garage or one outside. This outlet is typically controlled by a 10-15 amp circuit breaker. If you did not have an electrician run a dedicated line, it is probably “ganged” with other outlets inside the garage. If these outlets have anything plugged in such as an air compressor, refrigerator, freezer, or another item, they will occasionally draw power as well
I’ve heard: “Shouldn’t be a problem as I’m only running the refrigerator.” That is not true, as the distribution center/converter will also occasionally kick in to recharge your house batteries.
And this is the second part of the equation: What will be the actual power draw from your rig? The refrigerator will draw about 8 amps on 120-volt mode, and the converter will be anywhere from 6-9 amps or more. So you can see the issue when plugged into a 10-amp circuit.
Plus, if you are concerned about freezing water tanks, you will be running some type of heating system or tank pad – which we will cover in just a bit. My advice is to have a certified electrician install a dedicated line with at 30-amp breaker/outlet. This will protect you from overloading the circuit if you decide to run anything else in the rig. So, it’s important to know your power requirements and size accordingly.
One last, and very important. thing. Get an extension cord that matches your rig. Even the “Heavy Duty” cords featured at home improvement stores are typically only 15 amps!
Keeping tanks from freezing
As for keeping your water tanks from freezing, first I would ask how you are planning to use the rig parked at your house. If you are just keeping it plugged in to keep the batteries charged and not using it, winterize the water system with either RV antifreeze or blow out the lines with air. If you are going to use it occasionally, I would still winterize and keep jugs of water handy to use the toilet and sinks but not the shower.
However, if you are going to live in it, then you will need to check to see where your fresh water tanks are located. If they are above floor level, they may be heated and protected with the standard furnace. If they are below floor level, check to see if there is a heat duct going to the compartment that might provide protection. Even with that, I have found they are still prone to freezing due to insufficient air flow and cold pockets. So I install a small 120-volt heater in that compartment. Or you can look at getting a heating pad.
As for the holding tanks, just use the right chemical and pour a couple of gallons of antifreeze down the shower drain and toilet.
Related:
RVelectricity: How to install a 30-amp RV outlet at home
Read more from Dave here.
HAVE A QUESTION FOR DAVE?
Ask it here. Please be as brief as possible. Attach a photo or two if it might help Dave with his response.
##RVDT1732
Just needing some clarification… If I plug my 30 amp into a house plug, which is 15 amp as what I have read, can I turn on my refrigerator to cool down before my trip? Nothing else will be running during this time.
I connect my trailer exactly as you describe. I run some of the LED lights and the refrigerator with no problems. Obviously, I do not use microwave or A/C but I will sometimes use the propane furnace in addition to the refrigerator.
My mistake! It should be a 15-20 amp breaker that is standard. In my photo I noticed the 10ak listing on the lower breaker rather than the 20 on the switch and had an exhaust transfer of brain data which some people call a brain fart!
Dave, I think you are mistaken about 10 amp household circuits. In all my years as an electrician I have never seen or heard of a 10 amp household circuit or a 10 amp circuit breaker. General lighting and receptacles are always 15 or 20 amps
Brian, I live in a house built in the early 30’s. Outside where the power drop comes in I have a manual disconnect with a single 25a glass fuse below it. I never had to get adjusted to rv life on 30a.
You’re right.
Dave, you say that the outlets are typically controlled by a 10-15 amp breaker. When was the last time you saw a 10 amp breaker in a panel? That would mean that it is wired with 16 gauge wire. I don’t think any houses built in the past 60 years use that size wire.
16 gauge has never been used in house wiring AFAIK, even knob & tube was 14 AWG min. .
Back around 35 years ago I had a ceramic storage heating system in my house which the thermostats required 16 gauge. If my memory is correct the thermostats were 220 volts. Don’t remember what country the heaters were from. But 220 volts is common for household wiring in some countries.
Dave, I assume you mean to pour a couple gallons of RV anti-freeze down the drains and toilet to keep the grey and black tanks from freezing. Automotive anti-freeze should not be used in your RV.
Ditto.
Be sure to drain the hot water heater if you are not using it and isolate it from the water system before adding RV antifreeze.