Some of these conditions, such as over/under voltage are quite common and encountered in many campgrounds, especially during hot or cold weather when multiple rigs are running air conditioners or heaters. Your RV may have already suffered hidden damage from this as it does not usually cause immediate failure but accumulates damage over time until total failure occurs.
EMS vs Surge Protector
An EMS or Electrical Management System is somewhat like a surge protector on steroids. It offers surge protection as well as protection against these other conditions.
EMS devices are available with a range of protection, in portable and hardwired versions and models for both 30 and 50-amp RVs
When shopping for an EMS, take careful note of the faults it detects as some models offer a greater range of protection than others.
Portable models are popular as they simply plug into your power source and your RV's electrical cable plugs into the EMS. The downside of this format is that it may be subject to theft if not secured. Some models include a tether point to affix the device with a steel security cable or chain.
Hardwired models are wired into your RV, before its junction box. With these, you simply connect your power cable to a pedestal as before.
Some models provide indicator lights to identify faults, some include a fault indicator that can be mounted remotely and still others provide fault information through a smartphone connection.
If you have a 30-amp RV, you will need a 30-amp model and if your RV has a 50-amp electrical system, you'll need a 50-amp model. They are compatible with power adapters so if you connect a 50-amp RV to a 30-amp power outlet, using an adapter cable, you still have full protection.
Different makes and models may function differently but most interrupt the power when a fault is detected. When the fault has been corrected, the connection is re-enabled.
There are several brands of EMS devices available and most have 30-amp and 50-amp models available in portable and hardwired version. I am unable to recommend any specific make or model as each have a different feature set. Check the manufacturer’s website for specifications and features then choose the one you fell is best suited to your needs.