Powering Up - RV Enthusiast Magazine

Powering Up

by | Jul 1, 2022 | Electrical, RV/Motorhome, Safety

You should never plug in an RV before establishing whether the power is ‘clean.’ Here’s how to test your shore power connection — and protect your RV from inconsistent voltage.

Hooking up to 120-volt AC power seems like a no-brainer, but there are a few precautions that should be taken before plugging in the power cord. First, you should determine the quality of the power — meaning, is the voltage at a proper level and is the wiring correct? Utilizing a surge protector is paramount, and most of the newer devices have multiple protection segments. The better ones, like the Hughes Watchdog (hughesautoformers.com) have a delay feature that surveys the connection and will provide an “all’s clear” signal (and connect) if the power is safe for the RV. The Hughes surge protector is very sophisticated and offers Bluetooth connectivity to a smart device.

You should never plug in an RV before establishing whether the power is “clean.” If you don’t have a surge protector, at least use a multimeter or commercial monitor to make sure there are no issues with the power. If using a multimeter, make sure the probes are in the right position for an accurate voltage measurement. To check voltage on a 50-amp receptacle, put one probe in the bottom vertical slot and the other probe in one of the other vertical slots. After you get that voltage value, move the outside probe to the other outside vertical slot and read voltage again. Voltage should be similar. For a 30-amp circuit, put the probes in the opposing slots and read the voltage.

Of course, the primary job of any surge protector is to prevent damage from brown- or blackouts, inconsistent power and lightning strikes. Surge protectors come in 30 or 50-amp capacities and can be built in to the system or used as a portable plug-in unit. The latter is susceptible to theft; although not commonplace in most RV parks it does happen. Locking mechanisms can be purchased to offer a higher level of security — and are typically proprietary to the brand of surge protector — or you can fashion your own with a good lock and cable.

Hughes Watchdog surge protector
All RVers should get into the habit of using a surge protector when hooking up to 120-volt AC power. These units provide circuit protection against brown and blackouts, low/high voltage and mis-wired hookups. The Hughes Power Watchdog is available in 30- and 50-amp iterations and offers high-tech features like Bluetooth connectivity.
Example one of how the receptacle is configured for a 50-amp hookup box
Example two of how the receptacle is configured for a 50-amp hookup box
If your surge protector does not monitor clean voltage, which will intercede with the connection in the event of a hookup utility power issue, you can determine if the power is OK by probing with a multimeter. These images are representative of how the receptacle is configured in a 50-amp hookup boxes and how to use the probes.

One way to up the power ante in an RV park is to employ a Hughes Autoformer, which boosts low voltage by manipulating the amperage. For example, appliances that have minimum voltage requirements can benefit from the Hughes Autoformer where voltage is not up to par — as long as the rated amperage from the hookup is not being exhausted by appliance/accessory demand.

Power cords are relatively durable if they are not abused. Typically, the cords that are supplied with the RV meet minimum standards and are less pliable than aftermarket counterparts. For example, Marinco (marinco.com), a venerable supplier to the marine industry, offers easy-to-handle 30- and 50-amp power cords that offer excellent service over long periods of time, typically the life of the RV. They are not cheap, but quality is obviously better than the stock versions and are much less rigid.

Connection reliability is only as good as the hardware in the sidewall or compartment of the RV. In too many cases, hard-to-seat terminals end up arcing over time, reducing the quality of the 120-volt AC power. There is where the SmartPlug (smartplug.com) really shines. The company offers plugs and receptacles (30- and 50-amp versions) that provide solid connections and virtually eliminate arcing — and they offer ergonomic handling and secure locking. I’ve been using the SmartPlug system since its inception in 2007 and can tell you there’s no going back.

Adapters that make it possible to plug 30- and 50-amp power cords into other than their respective outlets should also be part of any RV’s supply arsenal. Typically, an adapter is used to connect a 50-amp cord to a 30-amp supply, but there are times when a 30-amp cord must be plugged into 50-amp service when multiple options are not afforded at the hookup box. Keep in mind that, regardless of the adapter and/or cord, power input is always dependent of the available service at the box and the RV’s circuit breakers. Only use adapters with attached pigtails — the all-in-one versions get hot and can arc easily and can be rendered unsafe.

Variety of power adapters
There are plenty of adapters on the market, which allow users to connect to just about any power provision. Common sizes are 50- to 30-amp and 30- to 15-amp, which will cover just about any situation. Adapters with pigtails are best, since the all-in-one models typically arc and short out more quickly.
Marinco counterpart power cord
Some factory provided power cords can be stiff and hard to connect. Aftermarket counterparts like this one from Marinco is high quality and very flexible — and the connection point is solid.
the Smart Plug
The SmartPlug power cord conversion is one of the best in the business. It’s available in 30- and 50-amp sizes and offers a secure connection that’s much easier to use and prevents arcing/shorting. Do-it-yourselfers can make the conversion without complications.
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