Tech Tips: Breaking Down Breakers

Maybe the end of summer is the time when circuit breakers like to take vacations. We ran into two separate incidents of RVers with circuit breaker issues within two weeks of each other. Since breakers seldom act up, when one does “go gunny bag,” it can be a bit of a mystery for RVers. Let’s take a short look into the world of these voltage interrupters.

Breaker Basics
Your RV “shore power” system is somewhat similar to your stix-and-brix cousin’s. Electrical power flows into the rig through a distribution panel. Once at the panel, the power flows to various shore power circuits through circuit breakers. These breakers act as safety valves, if you will, protecting the wiring of each circuit from overloads. For example, say a piece of equipment shorts out, the breaker detects the overload, and instead of allowing the wiring to become red hot (and likely start a fire), the breaker “trips” and stops the flow of current. Unlike a fuse, the circuit breaker is generally resettable, and once the problem is cured—in this case the equipment is unplugged—power to the circuit can be restored with the flip of a lever.

At the outset, we like to warn folks that electrical breakers should not be used as “switches” for circuits. Circuit breakers are designed as safety devices, and flipping them off and on like you would a light switch can lead to premature circuit breaker death.

We say circuit breakers are generally resettable because they can be damaged or wear out, at which point they’ll need to be replaced. We’ll come to that in a bit. First, let’s talk about how to reset a tripped breaker.

Resetting Tripped Breakers
If an RV breaker trips, you’ll generally know it because the power to whatever you were using will simply stop. For one of our recent acquaintances, a European couple traveling through the states in a rented motorhome, a long, hot summer night without air conditioning signaled their problem. We were able to help them with the fix.

First, you’ll need to locate your breaker panel. It’s a good thing to know where it is in advance, so when you need to check breakers, you won’t be in the dark (figuratively or literally) as to its location. In many recent RVs, the shore power circuit breaker panel is combined with the low-voltage fuse panel under the same lid, often attached to the power converter.

Next, look at all the breakers in the panel. You’ll be looking for one that’s leaning off to the side, or has perhaps a red flag in a window on the breaker. The leaning or flagged breaker is the one that’s tripped. Before attempting to reset the breaker, TURN OFF or unplug any equipment or load on that circuit.

Next you’ll reset the breaker. What can be confusing for some is this: You’ll often need to push the breaker lever toward the off position before flipping it back to the on position. If you don’t, it may not reset.

If the breaker immediately trips off again, it generally signals a fault in the wiring to the circuit—this is one reason you’ll want to disconnect or turn off everything on the circuit before attempting to reset the breaker.

With power restored to the circuit, begin to plug back in and/or turn on equipment on that circuit. If the breaker trips immediately when you flip something on, you’ve identified a defective piece of equipment. If power continues to flow, all the better.

Now here’s the caveat: In the case of our other RVing friends with recent breaker problems, the tripping breaker served their air conditioner. They’d reset the breaker and all would be well—for a few minutes. Then the breaker would trip out again. Obviously there was no “dead short” or gross overload, which led to the suspicion of a bad breaker. Partially contributing to their problem, however, was that they didn’t turn off their air conditioner before resetting the breaker. With the heavy load of the cooling unit, they may well have contributed to the demise of their breaker, which is why we gave our earlier warning about not using a breaker like a switch.

Circuit Breaker Testing
Breakers can wear out, or simply give up the ghost. Those that have been repeatedly tripped are often ones that finally give up the assignment and simply refuse to carry their rated load of current. Testing a breaker in the panel is not a job for the foolish; you’ll need to take the cover panel off, and touching the wrong thing can be harmful, if not deadly. If you’re at all unsure of your safety, take your rig to a qualified repairman.

Carefully remove the cover plate from over the circuit breakers. Each breaker clips into an electrical bus bar, which supplies shore power to the breaker. It’s CRITICAL that you not touch a live bus bar—here’s the serious injury or death issue.

At the other end of the breaker you’ll find the wire that leads to the circuit served by that breaker. With your electrical multimeter set to AC volts (set to 130 volts or more) touch one probe to the terminal screw on the breaker and the other to the terminal block where the circuit neutral wires come together—these will all be white wires. Assuming the breaker is set in the on position, if the meter reads no power, the breaker is defective.

But what if it’s one of those, “runs a few minutes and trips” situations? With all electrical loads “off” on the circuit, trip the breaker back and forth from on to off a few times. The lever should move through crisply without feeling “mushy.” Turn off loads on another working breaker, and run it through its paces for a comparison. A breaker that’s “wearing out” may tell the tale by how it “feels.” If in doubt, it may be best to simply replace the breaker.

Breaker Replacement
When replacing a breaker, for safety’s sake, disconnect your RV from shore power. Don’t run your generator, and if your rig automatically connects to a power inverter, make sure that’s turned off too. You want ALL power to the circuit panel turned off.

With the panel cover removed, grasp the breaker and rock it in the direction of the wire end of the breaker. You may have to rock it several times to get it to loosen, and then give it a firm yank. It may require a bit of muscle to do this, but typically the breaker will “give,” starting at the “wire end” and then slide out of the bus bar. Now remove the wire by loosening the terminal screw.

You’ll need to replace the breaker with an identical one. In RVs, you’ll often find that the “name” on the breaker may vary, but these breakers are often made by the same outfit, and then have a different label slapped on it. Some breakers have more than one lever and hence, serve more than one circuit. If one side of the breaker conks out, the other will keep working, but you will still need to replace the entire breaker. In the typical home, both sides of such a dual breaker will be of the same value, but not necessarily so in an RV. You can often get a suitable replacement breaker for a single or double of the same value at the hardware store, but if you can’t find what you need, by all means, visit an RV supplier. 

To replace the breaker, insert the wire into the terminal, and firmly tighten down the screw. It’s not a bad idea to check to make sure that wires to each of the breakers are firmly snugged up—a loose connection can lead to failure, even a chance of fire. With the wire in place and snug, slide the “head” end of the breaker back into its clip and firmly push the rest of the breaker into place. n

Russ and Tiña De Maris are authors of RV Boondocking Basics—A Guide to Living Without Hookups, which covers a full range of dry camping topics.  They also provide great resources in their book, Camp Hosting USA—Your Guide to State Park Volunteering.  Visit www.icanrv.com for more information.

Russ and Tiña De Maris