30 Aug 2016
|Campground electrical power is notoriously unreliable. There are frequently outages or “brown-outs”. Occasionally, the sites are wired incorrectly with poor ground connections or reversed lines. Knowing this, I had installed a “Power Surge Guard” when I first bought the RV more than a year ago. It detects all sorts of dangerous power situations but only has one protection approach. If it detects any problem, it shuts down the entire RV without warning.
For months, it worked wonderfully. On rare occasions, it would shut off the power, wait two minutes and then automatically resume it when it’s stable again.
Lately, however, it has gone off more frequently. In the past when it shut down, my rig had been drawing lots of power. For example, both air conditioners might be running, plus the water heater, plus some other device such as the microwave or the toaster. This didn’t seem too surprising, since a high load might cause a drop in the campground voltage, which the power guard might interpret as a “brown out” and shut down.
But, recently, it’s been shutting down more often. Sometimes only one or two high current devices were on. I checked around. No other campers at nearby sites were seeing any power problems. Whenever I checked the circuit protector, the lights were green. No problem. Of course, there was never a problem when I was looking!
Without my air conditioner on, I couldn’t work on the problem very long at a time. With a series of brief work details, I opened the walls leading to my internal electrical connections. With the power unplugged, I removed my circuit protector from the system and reconnected everything. I threw the (rather expensive) circuit guard in the trash. Now, at least, I had stable power but without a filter.
To my horror, at the next campground, I had more power problems. I could actually hear the power variations by listening to the fan. The pitch of the fan noise normally goes down momentarily when an appliance kicks in. Now, it was fluctuating wildly. Something is wrong. The problems are not being caused by the circuit protector, since it’s no longer installed. Something else is wrong. I unplugged my TV and my computer to protect them.
When the next power drop occurred, really bad things started happening. The surge protector for my computer literally when up in smoke. The washing machine stopped and wouldn’t restart. The microwave screen went blank. The air conditioner started making strange noises. I quickly unplugged from the campground.
I asked the maintenance crew to check the power. Everything at the campground passed every test. The problem has got to be inside my RV.
I brought out my electric test equipment and started methodically checking everything. One of my test instruments found a fault: “Open Neutral”. For those of you who don’t know much about 240 volt circuits, there are actually two, separate 120 volt lines (in opposite polarity). The “neutral” line enables either line to be used independently. An “open neutral” meant that my circuits were sharing the 240 line. (To be precise, there are now two circuits in series getting 240 volts total.) In practicality, that meant that my appliances could receive voltages anywhere from less than 50 to more than 200. That’s enough to fry most electronics.
Again, I unplugged my rig from the campground. It’s running strictly on 12 volt battery power. I can’t afford to plug back in until I’ve identified and corrected the problem.
I now have a sick or dead washer/dryer and a dead microwave. Without power, I can’t run my air conditioner or my AC fan. My only protection from the heat is now a couple of DC fans.
Further, I can’t open my washing machine. When I temporarily supplied power, the door still wouldn’t open. It made a few sickly clicking sounds but didn’t unlock the door. (Since my unit is a combination washer/dryer, it has a front-loading door.) I called the service line for the washer/dryer, their tech support told me how to open the front access panel and pull the secret emergency release. The tech warned me that, if it had water in it at the time, the water would come rushing out into my RV. I had no choice. I pulled the cord. The door opened. No water came out. Good. Now, I’ve got my clothes out but I still have no washer/dryer. I guess I’ll use the campground laundry for a while.
The microwave was yet another problem. How am I going to cook anything? My standard recipe for any meal is “microwave until done”. Most of the food in my RV is specifically designed for the microwave. Also, without campground power, I have no toaster. I have an oven but it’s difficult to light. I’m now limited to what I can cook on the gas range. I went to the local grocery store and bought some food that doesn’t require a microwave, such as: hamburg, beef stew, etc. At least I can eat hot food now.
I’ll have to figure out how to replace / repair things later. Right now, my primary concern is the heat. If I can’t get the air conditioner going, I’m going to be seriously overheated soon. The high temperatures could actually be fatal to my bunny, Pooka, since he’s wearing a fur coat.
Using a multimeter, I started running additional tests. I was able to confirm the results from the first test instrument. Yes, I have an open neutral. Yes, the other three lines coming into the RV are fine. Again, I open the walls and opened the power transfer box (that automatically switches between campground power and generator power). Finally, I concluded that the open neutral was between the box and the campground pedestal. Everything else checked out perfectly.
But, how could that be? There are no junction boxes between the transfer switch and the pedestal. Ah, but there is one socket. When I unplugged the power cord from the RV, I discovered that the outer plug had major burn marks and the inner plug had corrosion marks. Only the neutral line had been affected. The other three lines where fine.
In hindsight, the problem was now obvious. I’ve been having intermittent arcs in the neutral line, probably for months. Correctly diagnosing the fault, my circuit protector had been interrupting the power. Now, without the circuit protector, the fault was burning out equipment inside the RV. The problem was never with the circuit protector; the problem was this outdoor connection.
I replaced the faulty socket and the damaged plug. I'm up and running again! Full power!