Reverse Polarity code When Plugging in at Home

More common is connecting 240 volts and the fun starts immediately.

Sounds like a good outcome!

Reverse polarity on an outlet won't harm electronics because it doesn't change the sort of power the device "sees"; it's no different than plugging in an (unpolarized) plug flipped the other way over. Reverse polarity is problematic from a safety standpoint mainly because the hot line is the only one switched by a circuit breaker, so a tripped or shut off breaker doesn't cut off the power if the two are reversed. The normal current path is still broken, of course, so it still protects against a normal overload, but a short circuit to ground would not trip the circuit breaker where the polarity is reversed. If the fault current is sufficient, it would trip the circuit breaker in the house's electric panel where the polarity is correct.

It could be worse.. When they put in central air at my old sticks and bricks

The kid hooked the black wire to the green screw. (Hot to ground)

Well, I got home and plugged my EMS directly into the wall plug to test it and got the Reverse Polarity code as expected. I turned off the circuit breaker, removed the plug receptacle and reversed the wires. Voila! It works properly. This puppy has had reverse polarity since it was installed by a reputable electrical company! I’m glad that I hadn’t damaged any electronics in the RV. Thanks again for all of your help with, tool suggestions, pictures, etc. It made it easy for me to tackle this myself. Not bad for a somewhat mechanically inclined 66 year old woman! Most of you assumed that I was a man but at the end of the day, it doesn’t make any difference as we are all very capable of many things!??

Ken56, I believe that you’re correct. It was rushed at almost 2:00am as they were evacuated due to a fast moving fire. We were all pretty exhausted. But, that is exactly what I will do when I get back home as we all left the house yesterday. Thank you.

I’m sure that the wall plug is the problem as we used two different surge protectors. BTW, they are portable.Thank you everyone for your assistance.

Bobbo wrote:
Before I switched the wires, I would want to confirm that it is, indeed, the outlet that is mis-wired. Hence my recommendation for the no contact voltage tester. If he re-wires the outlet, but it was actually the EMS that was wired backwards, he has not helped himself.

Since the EMS appears to be portable I assume the premade connectors are wired correct.
If EMS was hardwired version done by the RV owner I would have more concern.
Either way the pictures show the correct wire placement.

Wait a minute, Why did he place the EMS in the middle between 2 cords? Why not put it on the outlet and that would tell if the outlet is miswired wouldn't it?? Obviously he has said he had to evacuate so the friend is not currently there. The situation should be corrected though.

time2roll wrote:
You can verify or just fix it.

Turn off power at the breaker, remove the connector, reverse the Hot and Neutral, replace connector, restore power.





http://www.myrv.us/electric/Pg/30amp_Service.htm

Before I switched the wires, I would want to confirm that it is, indeed, the outlet that is mis-wired. Hence my recommendation for the no contact voltage tester. If he re-wires the outlet, but it was actually the EMS that was wired backwards, he has not helped himself.

Dave H M wrote:
Bpbbo, If you hare some elcheapo HF volt ohm meters laying around already, won't they suffice for the testing?

The no contact tester will tell him immediately which wire is the hot wire. Using an el cheapo VM he will have to test each wire pair to determine which wire is hot. Just faster and easier. And safer since it is no contact and he can't shock himself. But, to answer your question, yes the el cheapo VM will give him that information, if he knows how to use it.