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Old 09-21-2016, 09:15 PM   #21
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"Hot" skin

If you have the common and ground connected together . . . you could have a non-grounded unit. If you have metal sides, walk out in the rain . . . touch the side of the unit you become the ground ! ! Old wiring, that was common practice. That's why the old 220 amp dryer circuits don't have a ground. with a 50 amp RV . . . need to add a ground in that situation. Remember in the 30 amp circuit, the common wire is the return line. Of course a/c current, the "hot" wire and the return line alternate. You need to properly ground your unit for safety of your equipment and more importantly, the things that breathe in your life. Man, I was all over the place with this answer . . . hopefully didn't confuse anyone (but myself)
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Old 09-21-2016, 09:48 PM   #22
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Daniel, the tech is correct that some surge protectors/ems do give a reverse polarity warning when it's not always the case. We have other threads on this, and I will try to find them.

However I wouldn't want to just discount it and totally take his word for it without further checking.

120 volt Reverse polarity in itself usually will not give you a problem as far as your RV is concerned for operating purposes, unless you also have a ground issue, then it can be real bad.

Here are some good links to peruse. I use the link below a lot and made a analog outlet tester as it shows how to under the outlet testing tab. Having an outlet tester like this would also confirm or deny what your surge guard is showing. This is a great site to bookmark and learn many electrical aspects from concerning your RV. You can also use a multimeter to check for reverse polarity at the outlet, and is explained in the link below.

RV Electric

how to make a 30 amp analog outlet tester shown in the link above;

Mike Sokol (whose is a member here) also has a great website and even a handy book you can get off Amazon that makes it easy for the novice Rv'er to understand and test for electric anomalies, some of which can be fatal. This link is to his website and you can peruse all the sections he has there.

RV Electrical Safety now available in Paperback and Kindle formats | No~Shock~Zone

Mike also touches on reverse polarity in this thread, which we keep as a sticky in the electrical section, as it also concerns hot-chassis condition.

So in conclusion, your surge guard could be telling you that you have a problem where you don't....or it could be correct. What brand/model is it?
2011 Flagstaff 831 RLBSS

If I eat myself will I become twice as big?...or disappear all together?
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Old 09-21-2016, 10:02 PM   #23
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I don't rely on a surge protector to tell me if I have reversed polarity. All you gotta do is place your tongue on the the metal siding and if your DW is suddenly $300k richer, then yes, polarity is reversed.
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