Originally Posted by Chance
Can you recap for us what the EMS does in your case? What's the benefit, and disadvantages?
If you search the internet and read RV forums much, you will run into stories where folks have ruined appliances because the campground's wiring was improper or because the campground's voltage dropped below safe levels or surged above safe levels. Occasionally you will run into stories of people being shocked (or worse) due to incorrect wiring of the campground pedestal. I personally ran into this twice in the last 12 years, not a big number but the first time cost me out of pocket $2300. By the end of that month 12 years ago, I installed my first EMS, and I have had one in every new RV I have bought sense.
You could buy a Polarity Tester and test every pedestal you hook up to first and if you tester shows a problem, you notify the campground management and move to another one and test it before hooking power up.
Now, the polarity tester does not test for improper voltage which can harm your appliances. but, you can get a combination polarity/voltage tester to do that job as well. It's a matter of (for me) will I remember on that cold night and all I want to do is get hooked up, ah, it will be fine just do it. OK so the next problem is OK, you were fine, but you cannot continuously monitor voltage and it won't prevent a voltage drop or a surge, which happens the more people on on a system in a campground, and it can even happen at home in your stick house. These drops and/or surges can damage your expensive appliances and electronics even more now-a-days as there are so many more electronics involved.
These devices (EMS Systems) will continually protect your RV and appliances/electronics from:
Mis-wired Electrical Pedestals
High & Low Voltage
Other Miscellaneous Electrical Problems
You can get them for 30-Amp rigs and 50-Amp rigs (50-Amp models work on 30-Amp circuits as well). They are also available in models that can be plugged in directly to the campground pedestal and models that can be hard-wired into your coach.
If you use the portable model that gets plugged into the pedestal, you simply plug it in and then plug your power cord into the device. But, I had my stolen off the pedestal while my wife and I sleep during the night, that was an expensive item. Just after than we decided to hardwire, yes, it cost a bit more, but it's still there and now I have a hardwired unit in my new motorhome.
With most models, there is a two-minute delay to protect your air conditioner. If all is okay with the circuits, it lights up and allows electricity into your rig. If there is a problem, no electricity is allowed in and warning lights are displayed, as in my system I have a remote panel that gives me error codes to check to see what happened. Again, if there is a problem, notify the campground management and MOVE to another site. You may have to move to another campground! We have done that as well, only once to be honest with you, but it let me know. We use computers, as well as some computers that now run things in our motorhome.
Once electricity is allowed into the rig, the device protects the coach from surges. Also, it completely shuts down power to the RV if campground voltage drops below or surges above certain levels. This protects your appliances.
There is also a time delay built into the unit that keeps the air conditioner from short-cycling. If the compressor turns off and on too quickly it creates extreme stress and the compressor can be damaged. The time delay is just in case the air conditioner is "on" when plugging in initially or if the air conditioner was running during a power shut down.
There are I believe two or three major companies that make these units, I have a Progressive Industries system, but there are others, you will have to check the internet and see what comes up, and if you do decide to purchase one or the other, check with Amazon, I got mine there for about 100 bucks less than the company and I still have the complete warranty.
I guess you could say, I have piece of mind sense I've had this unit. I paid once and swore I would never do that again. It may never happen to you, but not if, but when it does, it will make a believer out of you. That time it cost me 2300, add it up, a new TV, a new refer board, both of them, a heater board, and my wife's base computer that was plugged in at the time. This system protects everything at once now, yes, you could protect individual item like computer (surge control) and other modern items, but like I said it's piece of mind, and cheap insurance.
To answer your question, all are benefits, disadvantages, I see none.
I know a disadvantage; wiring the #10AWG into that unit, I don't remember that being so dang hard the last time I did it, it's tuff getting old.
This is the fourth unit I've installed in 12 years, I think this is the last one I'll be doing, we really like this MH.