So lets talk EMS systems on RV’s. Are they a good idea? What do they protect? Are they sometimes the problem?
Let see what they actually do. It depends on which model you choose. Some of them:
- Look for low voltage. If the voltage falls to low, it will disconnect the camper from the park electric.
- Have surge suppressors. This prevents over (high) voltage to the camper. If it sees voltage over a certain value, it disconnects your camper from the park electric. It can only do this a limited number of times. If this feature is overused, the until may eventually fail.
- Compare the voltage between phase one and phase two, (on 50 Amp only) if it is not balanced, it will disconnect your camper from the park electric.
- Look for phases that are not correct. (We have seen many of these defective and actually report a false phase problem).
They are also made a couple different ways. One style is just a black box that you plug into the park electric, and then plug your camper into it. The other style I would avoid like the plague. This style is one that is built in with no way to bypass it. Or, understand that if you have an issue, and your EMS system is hard wired with no bypass, you may be on your own for the stay. There may be nothing the park owner can do to rectify the situation.
The version that plugs into the park electrical pedestal is the better of the two in our opinion. And an opinion it is. With all due respect, here is what forms this opinion. We have seen a SLEW of these built in EMS systems with no way to bypass them falsely shutting off campers power for no “real” reason.
For instance, recently we had a motor coach in here with three AC units, an electric on demand hot water heater, electric only refrigerator. The EMS system on this camper was shutting down the power to the coach because it saw 108VAC on one phase, and 112VAC on the other phase. However, these EMS systems never get calibrated. Meaning, our calibrated meter shows 112VAC and 118VAC on the respective phases. Which would run anything you have. Needless to say, the owner of the coach becomes a master electrician and blames the park. When in reality, this EMS system either wasn’t calibrated or has a loose connection somewhere causing a fault that the campground owner cant do anything about.
If the EMS system was calibrated, or able to be bypassed, this motor coach would have had a better stay. In reality, there was nothing wrong with the power being supplied to his rig. But wait, are you saying the park owner doesn’t take any responsibility for this? Sure, we try too, we try to help. But when we walk up with a properly calibrated meter only to see the EMS system is wrong, and the EMS system can not be bypassed, we run out of options and feel terrible walking away without have a solution for the customer. We ALWAYS feel bad over that.
Are there times the park power is insufficient? I think when its 95 degrees or higher, or the “feels like” temps are hitting 100 or more, sometimes the power coming into the parks is getting hammered and sometimes is low itself. This is way beyond the park owners control. We had seen this in prior years, but as of 2023 the vast majority of the power in Triple R will be upgraded.
I hope this helps steer some into making sure that 1, if you install an EMS system get it calibrated every other year, 2, make sure you can bypass it.
OR Just purchase the version shown in the pick here, and save yourself the hassle of the larger purchase.
