As millions of people hit the road this summer for a long awaited getaway in their RV, campgrounds across America will be packed with people. And that means an increase demand for electrical power as nobody can “rough it” anymore with a single air conditioning unit and only one TV! No we have to have both roof airs going, 3 or more TVs, the pod coffee maker, microwave, and everything else. Electrical system and pedestals commonly referred to as shoreline power will be taxed to the max. So it’s important to understand your electrical system, learn how to check the pedestal for proper polarity and voltage, and know your limitations.
Let’s start with a basic understanding of how electricity gets to your rig. 120-volt power can be obtained from three different sources. The campground pedestal through your power cord, a generator either onboard or portable through a power cord, or from the house batteries which provide 12-volt DC power to an inverter that can provide 120-volt power to a select few items.
Since we are talking safety at the campground, let’s concentrate on the pedestal and the power cord. The cord can be permanently mounted inside the service compartment, or a twist plug like the unit in the graphic. Either way, the 120-volt power goes to the distribution center located inside the coach.
Inside the distribution center you will find a main circuit breaker that shuts off all power, and individual circuit breakers for the various appliances and wall outlets. In most RVs you will also find a set of automotive fuses for the 12-volt operations although some manufacturers have design a separate set of push button type fuses located in another compartment.
Power from these circuit breakers is routed through wiring known as Romex to the appliances inside cabinets and sometimes even embedded in the walls and ceiling during manufacturing. That is why it’s important to check for wiring before adding anything to your rig that might require installing a screw into the wall or ceiling!
Back to the pedestal. Most campgrounds offer a 15 amp, 30 amp, and sometimes 50 amp connection.
These all have a hot, neutral, and ground wire and can only be plugged in one way. The 50 amp connection has two hot wires supplying the distribution center so it can handle a larger load. Before plugging into the campground source it’s important to check the make sure the pedestal is wired correctly and has proper voltage. This can be done with a variety of devices such as this digital tester.
The voltage should be at least 110-volts and not more than 124-volts. Lower than 110-volts will still run appliances, however they will run slower and could cause damage to items like the fan motor in your air conditioners. If you are plugging into a 30 amp outlet, you will need to use an adapter to check the voltage. If you plan to use the 50 amp outlet you will need a different tester.
Another option is a multimeter which will tell you the voltage of any of the outlets.
First, become familiar with the multimeter and the outlet. Set the dial to AC which is the squiggly line under the A and hold both probes in one hand. This will prevent electrical current from going through your body if something happens. On a 15 amp outlet place the red probe in the small slot which should be the hot wire and the black probe in the larger slot which should be the neutral. You should have a reading of 110-120-volts.
To check for a properly grounded outlet, keep the red probe in the small (hot) slot and move the black to the ground which has a slight rounded side. The reading should be the same, if not it is not properly grounded. Refer to the graphic above.
On a 30 amp outlet refer to the graphic as well and see the hot is always counter clockwise to the ground hole. Typically the outlet should be mounted with the ground hole at the top but always take caution first.
A 50 amp outlet will have one hot wire or slot on each side and the ground to the top with a rounded side as well. Each hot slot should have 110-120-volts.
While this method will help check proper wiring and voltage at the time of measurement, it does not help monitor what the voltage does while you are at the campground and the temperature starts to rise and the hundred other rigs start to plug in. That’s why it’s best to get a surge protector such as this popular model from TRC that not only acts as a surge protector in case of a spike in voltage, but also shows the voltage, correct wiring, and amp draw that your RV is pulling.
A few final tips:
Always shut off the main circuit breaker before plugging in any device to the outlet and turn it off again when disconnecting your power cord.
If you need an extension cord, use the same gauge as your shoreline power and do not go any longer than 25 feet.
Water and electricity do not mix! Standing water around a campground pedestal is dangerous. If the pedestal or your cord is in standing water, stay away and get a qualified electrician and the campground management to come and drain the water and verify it is safe.
About the author: Dave Solberg: Managing Editor, RV Repair Club
For the last 25 years, Dave has conducted RV maintenance and safety seminars, developed dealer and owner training programs, written RV safety and handyman articles, authored an RV handbook reference guide and logged over 100,000 miles on the road in an RV.
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