Electrical question

trailerbikecamper wrote:
Did some testing and found that all three wires on the cord end that had just been replaced were in the wrong place.

Two problems: One.. Usually it is men who do the wiring.. Color blindness is a sex linked trait.. Men are often color blind.. I am to a mild extent.

Two.. Many times all 3 cables, in an RV park, are BLACK. it's up to the electrician to keep 'em properly labled.

Receptacles and plugs are always polarized for safety reasons. The only exception is anything that is double-insulated like power tools which can be used in the correct or reversed polarity.

The wide slot in a 15/20 amp 120 volt receptacle is the neutral. A white neutral conductor should be connected to the screw terminal with a shiny silver/chrome looking finish and the hot black conductor to the brass looking screw terminal. However, this is not a 100 percent guarantee that it will automatically be safe because there is a chance that the hot and neutral could have been reversed in a junction box somewhere or panel. If you have a run of receptacles showing reversed polarity, check the panel. A previous homeowner could have been in there that didn't know what he was doing.

On light bulbs that have screw bases, the larger outer shell surface is connected to the neutral and the tip is the hot connection so you can't accidentally touch the lamp base and get a shock. Receptacles are polarized so that if the casing/exterior/enclosure of an appliance, device or piece of equipment, etc. has an internal fault, any exterior metal part you touch won't be at 120 volts.

Just for fun, check the receptacles in your RV. I found two in our TT that were reversed. Reversed polarity in an RV an create a potentially lethal "hot skin" condition.

Wa8xym- had something similar happen. At a seasonal rv park, when caretakers came to me asking for my help. One of the campers had no power. Did some testing and found that all three wires on the cord end that had just been replaced were in the wrong place. Hot was on the green, ground wire was on the screw that should have been on and white was where the black should have been. This was making the whole trailer live, but it was blocked with wood creating an insulation barrier to ground.

Found it by testing from trailer ground connection point to actual ground. Literally stuck one meter lead into the ground, and read 120V from trailer ground to real ground.

Let me tell you of the WORST case of polarity reversal I have ever seen.....

Had central air installed on my house.. Got tired of messing with the window jobs.. Well when we finally charged it and turned it on POP went a fuse.

Replaced it happened again
So the techinician started trouble shooting

I forget which was the screw and which was the wire but the "Kid" who hooked it up put .. Thinking about I'm fairly sure.. The GREEN wire on teh BLACK scew and the other way around... No surprise POP went the fuse.

Thanks for the info guys. I have checked and corrected several of the outlets and they are definitely hooked up wrong.

I didn't even think about the switches.

Yes fix them all. Considering the scope I suggest calling an electrician to check everything such as that the switches are on the hot and not the neutral.

Yes this is important. When you turn something off the item remains energized because of the reverse feed.

Check the outlets with your multi-meter...
This is what you should see if they are wired correctly..

You shouldn't need to change the sockets, just make sure the wires are connected to the proper terminals. It sounds as though someone was wiring them up who didn't know or care about whether the hot or the neutral went to the brass or the silver terminal on the socket.

Reversed polarity is primarily an operator safety concern; it won't hurt devices that are plugged in. It will, for instance, mean that a lamp plugged into the outlet will have the outer shell of the light bulb socket hot (even when the lamp is switched off), and can thus pose something of a shock hazard when changing the bulb without unplugging, or even when groping around for the switch if you're particularly unlucky.

Before doing too much, I would check again that the monitor is giving you accurate information. A little neon test lamp would suffice for checking the outlet (or, slightly more sophisticated, a plug-in three light tester that has three indicators mounted together in a plug).

Incidentally, the things on the wall of your house are "outlets" or "sockets." "Plugs" are the gizmos on the end of the electrical cords that get put into the outlets. Usually the difference in words is somewhat immaterial as the proper one can be determined from the context (as in your question), but every once in a blue moon using the wrong one leads to all sorts of confusion.

Have you checked the accurate result of your new monitor by removing a receptacle and inspecting the wiring?