Chasing electrical ghosts – Backgrounder


Grand Coulee Dam Washington state. We spent a day visiting here and this is where our converter died in November 2013.

Electricity in general is pretty intimidating to the average person even though most of us use it all the time. We generally hire electricians to rewire in our house because the law requires it and if we don’t, we can’t get proper insurance or we might void the insurance we have. Electrical systems in houses are actually less complicated than most electrical systems in RVs. All that being said, your RV is going to have electric issues at some point and an understanding of how the system works will save you bucks and maybe a long stay somewhere while technicians who don’t really know what they are doing end up fiddling with one thing after another at your expense. Yes, there are some good RV repair places out there with electricians who know what they are doing. There are also honest used car salesmen out there too. Nice guys if you can find them. Because those kinds of people are so rare, it behooves the RV owner to get to know their rig’s electrical system at least as well as they understand how to drive their rig. Fortunately, with only a few tools and a little know how, you can diagnose and even repair your own electrical work. In an effort to share what I learned, I will do two posts on the topic, first on the normal RV electrical system in general. Second I will tell the tale of one our own adventures chasing electrical ghosts.

First the basic introduction. Your RV has two power systems. One power system is run off your house battery or batteries. This is the 12 volt DC system. DC stands for direct current. 12 volt is what your battery typically puts out. (Just to be particularly pedantic it is possible to have a 6 volt battery. The principal is the same.) This DC 12 volt system powers everything in your rig that runs when you are not plugged in to shore power. In my trailer, this system powers the refrigerator while cooling on propane, the furnace ignition allowing it to burn propane, the radio, the lights, the slider, the tongue jack in front, the four stabilizer jacks, and the hot water heater when heating the water without propane. To figure out what parts of your system are on the 12 volt, you should experiment by turning things off and on and figuring out what does and does not work without shore power. A general room of thumb is all the essential stuff you need while driving down the road, or when you pull into a campground but have not had a chance to plug in yet, work on the 12 volt. A wise owner knows what is on her rig’s 12 volt DC system and what is not. I recommend learning this long before something goes wrong.

The second electrical system you have in your rig is the shore line system. First a word about the connections. Your rig is either 20, 30 or 50amp powered from the shore. Mine is 30amp. I have seen very few trailers with only 20 amp (regular single outlet plugs like in your house). These are small units like tent trailers or much older units. 30 amp is common in all older rigs and new midsize rigs. 50 amp is needed for larger, newer and better equipped homes, especially the motorcoach type or those huge fifth wheelers common at the best RV resorts. Not all campgrounds have all power sources.

Plugging into the wrong amp system can be a very bad thing to do. Fortunately, it is hard to accidentally plug your unit into the wrong amperage because electricians have carefully designed standards for prevention of electrocution of ignoramuses. Each plug type has a different shape and a different connector. It is possible to connect a 30 amp plug to a regular outdoor house plug with an adapter. (Handy when parking in your kids’ driveway.) When you do so though, you have to keep in mind that your rig can draw a whole lot more power than that 20 amp plug is designed to deliver. If your rig draws too much power, the result will be a blown breaker or fuse inside the place you are plugged in to. This can be very bad if you are outside a friend’s house and they have gone for the weekend without leaving you a key to get in and there is only one exterior plug.

Sometimes those fuses and breakers can feel like a real pain. Nonetheless, whenever you curse one you repeat to yourself. ‘Breakers and fuses are my friend. They keep idiots, including me, from electrocuting ourselves and burning things down.” (More about them later.)

The same rule of ‘don’t draw too much power’ is true of using an adapter to plug a 50 amp unit into a 30 amp plug with an adapter. When you are using an adapter to get to a smaller power source, some things in your rig may just not work at all. Our rig’s air conditioner does not work if we are plugged into a 20 amp plug. Turning the air conditioner on does not blow a fuse. The air conditioner just sits there and does nothing. The rule is never plug your rig into anything where the plugs don’t match unless you use an adaptor designed for that purpose. If you use an adaptor, you need to adjust your draw from your land line to allow for differences in amperage over the adaptor and your rig.

The place you plug your rig into can also be problematic in a number of other ways even if the plugs match. For example, if there is a power surge in the system, such as during a thunderstorm with a lightening strike, excess power can come shooting through your land line and blow out stuff in your trailer. Plugs can also deliver less power than they are supposed to and so your land line plug overheats and it can melt things and cause fires. Low or fluctuating power can also damage electric stuff in your rig even if fuses and breakers accept it. The wise owner will install a power surge protector and power supply monitor. This is what we did when we first got the trailer.

There are two kinds of power surge protectors and power supply monitors. One kind sits outside between your rig and the campground power. These outside ones are of various capabilities and reliability. Some protectors also only do surge protection and not monitoring. Both are needed. The kind we have is generally more expensive and is mounted inside the trailer. The built in protectors do usually cost more but they usually have more features and are more likel to have the monitor in adition to the surge protection. They also have the advantage of being far less likely to walk off one night while you are sleeping. It’s also really hard to forget to use the protector when its hardwired into the system even if you arrive late at night and are exhausted and it’s dark. The power from the campground runs through our power cord, gets checked by the surge protecter/current monitor and then it is allowed to flow past the device and into the trailer only if is meets a certain standard. The surge protector is like a silent guard, always on alert.

We paid $250 to have it properly installed and it has paid for itself many times over. Once when we were camping, a lightening strike destroyed most of the electrical appliances on an entire street of rigs at a campground. Our surge protector detected the lightening surge and shut down and we had no damage except to our nerves. We were saved another time from a power surge that caused a transformer to blow while a squirrel committed suicide by climbing into it. Another time, low power from the campground resulted in overheating at the plug and the surge protector detected this and disconnected us. The cord at the plug was partially melted and the copper ‘sticking-out-thingies’ were burnt black. I have no doubt there would have been a fire without the surge protector.

We have now covered the power coming into your second electrical system. Where does it go? That power coming in is 110V and it is AC, as in alternating current. Alternating current is superior to direct current because direct current gets weaker the farther away you get from the power source. Alternating current stays constant along wires and can travel for great distances. Don’t ask me why. I got a D in first year physics where I was supposed to learn to understand that. I have since just accept it as a truth in life. The oven and dryer in your stick house is likely powered by 220V AC power. I have yet to meet an RV that had any 220 appliances, nor have I ever seen a campground with a 220 plug. One less thing to worry about.

The AC electricity comes into your trailer (hopefully past a surge protector/monitor) and travels to a fuse box or breaker panel somewhere in your rig. I strongly advise finding that panel and getting to know it before you have any trouble. Try switching each breaker off and on and locating what works on what breaker. Don’t go by the panel directions someone else wrote down because they are usually wrong. When you finish your testing, make sure to correct the written labels on the breaker box because you will never remember them again later. I also recommend pulling out every fuse, one at a time and determining what the fuse disconnects. Remember, the fuse protects everything it disconnects. Fuses are your friends.

Somewhere in that bunch of fuses will be one or two that blow specifically when you put the battery terminals on backwards. (Another example of the cleverness of electricians in protecting us.) In my rig I have two 40amp fuses specially dedicated to that job. I don’t recommend testing that fuse by switching the battery cables for yourself but isn’t it nice to know that when you do by accident, there are fuses that will blow before anything else is destroyed? After you have determined all the fuses you have, make a list of the size and color. They come in different colours and different sizes like 15, 20 and 30. Go out and buy a package of each type of fuse you have and keep it in your electrical toolbox. There is a Murphy’s law about fuses. If you have spares around, they never blow. You will not only save yourself a lot of hassle, but you will often make new friends, get free beer, pies, and other goodies in trade from all the other people in the campground who don’t have spares handy. Somewhere on that electrical panel is also information about the company that made it and the name and model number. It is a very good idea to write that down and search the internet until you find the wiring manual. The wiring manual will give you a lot of information about what is connected to where and is extremely useful in diagnostics when something goes.

There is one other idiot proofing piece of equipment you need to find. This is a special plug designed to shut itself off when some moron has connected himself between the 110V and water. This special plug is usually in the bathroom for obvious reasons. It has a test button and a special reset button, usually red. The little red button pops out when it saves you from electrocuting yourself. This special plug is also your friend. In many rigs this wonderful buddy is doing double duty in more than one place. For example, in my rig, if my special friend in the bathroom pops that red button, the plug in the kitchen shuts off as well. If my tea kettle boils over and the plug ends up lying in a puddle of water my buddy plug in the bathroom also pops the red button.

A lot of trailers also have a master light switch which must be turned on for all the other lights to work. It is normally located near the main door. Another tricky master is often for the bathroom ceiling fan. The ceiling fan can usually be shut off at both the switch on the fan itself and at the bathroom light switch. It is much better to deliberately test this stuff yourself and find out what it is connected to what and which shuts off stuff and turns it back on than it is to pay for a service call to have someone teach you this. Also, there is another Murphy’s law about flashlights so you are better off being able to find and throw these switches while groping around in full dark at a remote campsite on a moonless night if you already know their approximate location.

Back to our two electrical systems. Another one of those truths in life is that because of the way AC and DC are different, they cannot be directly connected. If you directly connect AC and DC, fuses blow and sparks fly and nasty stuff happens including the untimely death of expensive electrical appliances due to collateral damage. To connect the two systems there must be some kind of converter in between. The converter is normally located beside or below your electrical panel. It will have a cooling fan that turns on when it is working hard. If you can’t find it, turn everything off but the lights and then turn on all the lights and listen for a fan motor. This will reveal where your converter is.

The converter in your rig has two jobs. The first and most important job of the converter is to keep your house battery charged when a rig is plugged into shore power for more than a day or so. All the stuff that runs on the 12V battery system runs ONLY on 12 volts. So while a vehicle is parked, they draw off the battery. If you don’t have a way to recharge that battery, stuff will stop working once the battery is flat. In our rig that takes two days of regular use. Plus it isn’t good for batteries to go flat over and over. They tend to stop working in a much shorter amount of time compared to their usual 5 years lifespan if you keep dropping them to death’s door. The converter changes AC current to DC and delivers a slow trickle charge of DC power to the battery to keep the battery happy and full of electricity.

The second job of the converter is to boost the 12V system by supplying extra power from the land line plug to the 12V system at need. That way, if you are plugged into a plug, the power that your lights use will come not from your battery, but from the shore plug. The same wiring is used. The converter just takes that AC current coming from the shoreline and turns it into DC and sends the power on its way through the same wiring. Because the converter is supplying a trickle to the battery, a low amount when you are watching TV, and a large amount when you are cooking dinner, converters typically have three settings. You can hear the difference by listening. On my converter at low amounts there is no fan noise. On the midrange demand there is a quiet fan noise. When demand is high the fan goes into loud mode and really seems to work hard. It is generally a good idea to try not to leave the poor thing working at full mode for a long time. If I hear the converter is really working hard, I will go around the trailer and turn off lights and appliances until it stops.

All electrical equipment has a life span and things will die in your system and need replacing. Fortunately, they generally give a warning before outright dying. Electrical stuff also doesn’t like to be abused. Water is bad. Rust and corrosion related to water (especially salt water) and fog or mist, is bad. Jiggling and bumping while traveling down the road is bad because it loosens stuff. Electricity likes traveling on nice tight connections. It doesn’t like jumping across spaces or moving between loose parts. For reasons beyond my ken, spiders love to make nests in external electrical wiring and trodents like to chew on them. This is bad. All sorts of these kinds of bad things can cause trouble but usually give a warning first.

It is much better to recognize and fix an electrical problem when symptoms first start than it is to wait until something outright dies. This is because electrical systems work as a whole and if one part is not right, the other parts can sometimes compensate for a while. However, if they are doing something they weren’t designed to do, they will fail much sooner than they normally would. So, for example, if your converter is going, it will make your battery work much harder and thereby shorten the life of your battery. If you leave one thing until the entire system fails, you will quite likely find you have more than one thing to fix.

Warning signs that something needs attention are blowing fuses or breakers. Remember fuses and breakers are your friend so if they trip or blow they are trying to give you a message. Breakers also blow when things heat up. Each time the breaker trips is one less time it is able to do so. The breakers do wear out from use and the heating of the wires is also hard on the wiring itself. Therefore, each time a breaker clicks and cuts off power you should think of it that as a message saying you are playing with fire and you should stop doing this and lighten the load on the system. Just because you have enough plugs in your rig to run your air conditioner, fridge, microwave, tea kettle, TV and rice maker at one time, doesn’t mean you should if you regularly blow breakers while doing it. (This is also why 50amp is much more popular than 30 amp in those bigger rigs.)

We had one problem in our kitchen area. There are two plugs and I use a lot of little electrical appliances for cooking. I had an extension cord so I could plug in up to six appliances at one time. I found I was flipping that breaker a lot. I stopped this by doing two things. I got rid of the worst offender, my 1500 watt kettle that often blew the breaker all by itself. I replaced it with an online purchased 600 watt kettle. The new kettle boils water almost as quickly as the old 1500 watt one did, but it doesn’t trip the breaker every other time I use it. I also added an inexpensive extension cord with its own breaker style surge protector to my extension cord. That breaker flips before the main one in my system if I accidentally forget and turn on the rice maker, the electric fry pan and the kettle together. The little extension cord cost me $9 at Ace Hardware and its a lots less than the cost of rewiring my electrical system.

Now a few more things to keep in your electrical toolbox with the spare fuses. I recommend having a pair of high quality electrical wire strippers and a pair of wire cutters; one big and one small. Wires come in gauges from 1 which is really thick, to 18 which is really thin and common in speaker wires. RVs have two electrical systems so you will typically be dealing with big wires from about 4 gauge commonly needed for DC current at the battery and to thinner wires common in AC. I always use long needle nose pliers because they are so handy. I recommend carrying one of those too. Electrical tape, the real stuff, is essential and getting a combination role with different colours is not a bad idea either.

We also always carry a few some assorted sizes and types of connectors for connecting two wires. It’s also a good idea to have a selection of those little caps that go over the end of a wire and connect it to a ring. The ring then goes over posts and terminals. If you have two connectors of each size you’ll be ready for most emergencies. If you are on the road and need to buy them you can get parts at auto parts stores for the DC part of your system and home hardware places for the AC parts. RV places often sell both types but charge a lot more and are less likely to be open on the weekend when you need them. In our experience electrical disasters only happen in the middle of the night when you are far away from any city or on a main freeway in Los Angeles on a Sunday morning of a long weekend where the exit ramp lands you in the heart of south central LA. (Yes, that did happen and I intend to write about that adventure when I do the section on dogs and security.)

Finally, and most important of all, is a reasonably good multimeter. A multimeter is a handy device that has two wires that end in two pointy metal tips. By putting the red tip on the positive side of an electrical source and the black tip on the negative side, it is possible to measure if the current is present and how much is flowing if it is. I have a “smart” multimeter which I like because I don’t have to guess what I am supposed to be checking. If I use the smart multimeter on AC is adjusts and gives me the correct reading. If I then use it on a 12volt DC battery, it adjusts again and gives me the correct measure for that situation. I don’t have to think about resetting dials between tests. Not everyone approves of the smart ones. Some people feel it is important to understand the system enough to know which setting you should be using and if you don’t, you have no business using it. The price on multimeters ranges from a few bucks to several hundred dollars. Each is designed for specific needs and professions. Shop around a bit and choose one just good enough to do what you need it to but don’t pay for more than that.

I have now described enough of the background knowledge you will need to understand our adventure chasing electrical ghosts and how we finally busted them.


About tumbleweedstumbling

I have three blogs, embryogenesis explained, tumbleweed tumbling AND fulltimetumbleweed. I am a scientist, and my husband and I have written a book which was published by World Scientific Publishing in Nov 2016 called Embryogensis Explained. Full time tumbleweed was my first blog which I worked on during five years of living full time in a travel trailer. I have now retired that blog in favour of Tumbleweeds Tumbling since we bought a stick house in April 2015 and are no longer full-time. I have a blended family of five sons and one daughter, all grown up now. I am (step)grandmother to nine boys and one girl. My husband and I have a dog and a cat. We spend summers in Manitoba, Canada, in a 480 square foot house on a half acre of land in the tiny town of Alonsa. We spend winters in the USA. My husband is retired and being a US citizen, he does volunteer work in winters for Gulf Specimen Marine Lab in Panacea Florida as their emeritus. I retired in Sept 2013 and so far I am loving it.
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