I too never had an EMS on my first RV and do remember not having power at some peds (stayed in all kinds of remote, little RV parks for work) but never knew why; just moved.
I now use a SurgeGuard portable which I like better than the Progressive due to the readout IMO. The drawback to them until recently was that Progressive had a lifetime warranty and SurgeGuard did not; now they do. With the portable it does have the possibility of walking off but if you take some minor, cheap, precautions the likelihood of that happening are remote. I just leave it connected to the power cord all the time when we connect/reconnect. The built ins have to be installed inside and require some rewiring. When you sell/trade the unit you either have to uninstall then reinstall it or let it go, buy another and reinstall again.
You can have a defective power ped and still get power and never know you have a missing ground etc. I won't stay in a site without a ground because I don't want to be the conductor in the event of an issue and fry (or any of my friends/family). I've been to many campgrounds now that have power problems, some very apparent, some not so much. Went to a campground up in the mountains during deer season; plugged in my 50A and one leg was dead with no ground. Went thru the campsite with a meter until I found a ped with correct power (most did not) and set up. A guy in a small 30A trailer pulled in and set up in a site I had checked (one leg of the 50A missing, no ground) plugged his 50/30A adapter in and he was happy. I am sure the one side of power was good but he still had no ground. I advised him of that and he didn't care.... Just sayin that an EMS could easily keep you from cooking your goose....errrr, turkey???
