A number of suppliers now provide such protective devices for the RV industry. Surge protectors act like an electrical sponge of sorts, absorbing excess voltage, thereby protecting the entire coach. The surge protective device should include the ability to completely shut off the incoming power before damaging transients can reach sensitive on-board equipment. Additionally, they should have the capability to monitor and detect both high and low voltage conditions and to interrupt the incoming power until the system has returned to safer levels over a period of time.
Many surge protectors utilize a component called a MOV, (Metal Oxide Varistor) to protect against transients voltages. The quality devices usually have a minimum of three MOVs in the circuitry. More sophisticated protectors, such that might be used in the computer industry, have what is called sine wave tracking which actually tracks the incoming AC signal and literally cuts off the top portion of the wave. It provides better protection for highly sensitive equipment. The key to this technology is determined by the “clamping voltage rating” also called the “let-through voltage rating.” The lower the rating, the better the protection. Sine wave tracking protectors have a remarkably tight clamping voltage surrounding the incoming power line sine wave.
Some companies extol the Joule Rating of their surge protection device. A “joule” is a measurement of energy that indicates the amount of energy that a device is capable of absorbing. The total number of MOVs in a device primarily determines its joule rating. Unfortunately, there is no standard for measuring the joule rating of surge suppressors, but generally those with a higher rating are considered better. It is felt by many in the surge protection business that the joule rating of a surge suppressor is less important than the “let-through voltage” rating. Underwriters Laboratories, (UL), has, however, developed a minimum standard for spike suppressors. The surge protector you choose to install in your RV should meet or exceed the requirements of UL 1449.
You are encouraged to investigate the feasibility of adding transient voltage protection to your electrical system. If you truly value the electrical equipment in your coach and are well aware of the consequences, it can be considered cheap insurance at the very least.
That said, you should obtain the surge device that is properly sized for the ampacity of the shoreline cord. If you have a 50-amp coach, get a 50-amp surge protector. If it’s 30-amps, yep, go with a 30-amp version. If you must use a 50-30 adapter at some point, just keep the surge protector between the 30-amp adapter and the shore cord.
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