That is a GFCI (Ground Fault Circuit Interrupter) outlet. I showed it in a horizontal position because that’s the way the one in the bathroom area of our 5th wheel is mounted.
GFCIs are safety devices that have been around since the 70s – first required for electrical outlets around swimming pools in 1971, national electrical codes now specify their use for any circuit in a potentially damp location such as outdoor outlets or outlets near the sink on a kitchen counter. RV manufacturers have included at least one GFCI on all rigs built since 1978.
The GFCI plug typically provides the power to several other plugs. They are usually wired like this:
Our GFCI plug controls several outlets in the kitchen, a couple of plugs on the outside of the trailer and the A-C power to the refrigerator.
The GFCIs have an internal circuit that looks for any difference of potential between the neutral and ground legs of the plug, and they are designed to trip – open the circuit – if they register any current flow (as little as five milliamps) between the two.
Circuit breakers are installed to protect appliances and to keep your house from burning down. GFCIs are much more sensitive, and designed to save lives.
The sad truth is that GFCIs are a pain in the ass.
They don’t just open when they are supposed to. They are likely to pop anytime there is a power surge. Ours will often open when we have a power failure – or when the generator takes over after a loss of electricity from the light company.
You are supposed to test them monthly by pressing the black button, but if you do, it won’t be many months before pushing the red button will no longer cause them to reset. The more often they open, the closer they are to total failure. Because of that, I never test ours and don’t know anyone who does.
Our home was built before GFCIs were required and we have got along just fine without them. I know that it only takes one incident to prove their worth, but the chances of that happening are probably somewhere near the odds of being run over by a stolen school bus.
The GFCI in the trailer went out again for the umpteenth time, and the replacement was either bad out of the box or failed as soon as power was turned on. Now it won’t reset, either.
I’ve just about decided that there is such a thing as being too safe, so, at least for the time being, I am replacing it with a standard outlet.