That OTHER Circuit Breaker


The other day I commented about the fact that when our friend Debbie and her dad came to visit that we had electrical problems.

Circuit Breakers
It’s a cute little breaker box, isn’t it!

I’m contemplating the vagaries of motorhome design.  Our new-to-us coach has a very conveniently located electrical panel. The panel is in a covered overhead storage bay on the curbside of the coach just forward of the back wall.  That makes sense because the batteries and inverter live directly below — in the rear two curbside storage bays.  In our Winnebago the electrical panel was on the end of the bed, down on the floor, behind a metal cover hinged at the top which kept trying to close while you were laying on the ground trying to see the circuit breakers.  [mumble, mumble, mumble]Our Electrical Cabinets

And the question comes to mind:
Given the fact that there is a perfectly nice electrical panel with excess space to the right, why did the engineers put all of the lounge outlets onto a circuit that terminates not in the electrical panel, but in a separate sub-panel on the side of the Inverter?

Magnum-InverterThe  inverter is a nice enough piece of electronics.  The original one (before our addition of solar panels) was a modified sine wave inverter, our new one is a true sine wave inverter but both of them had the same external circuit breaker setup.  And why they would put that OUTSIDE the coach is beyond me.

pure sine_mod sineI know some of you who are (like me) not terribly savvy about electronics may not know a lot about RV electric power.  If you have batteries in your RV and you want to run regular household appliances you need to convert that 12 VDC power into 110-120 VAC current.  The inverter is the machinery that does that work for you.  So, seeing as the inverter’s job is to change one kind of electricity into another — just why they put a 110 V circuit breaker down there on the the equipment that converts one kind of power into another is an obscure mystery.

The difference between the two forms of electrical waves is that the modified sine wave is cheaper to produce (cost of original equipment) but it gives you a voltage with … for the lack of a better term …. sudden jolts.  The power goes from zero volts to +110 volts instantly, then instantly back to zero volts and then instantly to  -110 volts.  A Pure Sine Wave inverter gives you the same 0 to 110 to 0 to -110 to 0 pattern, but in a smooth wave form, and not that jarring form that can be hard on different kinds of electrical power.  The more electronics you run the more susceptible you may be to problems.  Many machines will work just fine with modified sine wave; and as the modified sine wave inverters are developed and electronics are improved the problems seem to be lessened but they can still result in premature appliance failure.

The long and the short of it is that we found where our extra two circuit breakers are.  And now if we trip a breaker and we can’t find a tripped breaker INSIDE the coach we just go OUTSIDE and sure enough — there’s the little troublemaker!

And thus endeth our dissertation on strangely placed circuit breakers.  Thanks for stopping by and I’ll talk with you tomorrow.

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2 Comments

    1. Its curious, the choices engineers make. In some areas HR seemed to have gone to great lengths to do things right — in other areas, not so much.

      At least once you understand you can be prepared (keep your fuzzy slippers handy) 🙂

      >

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