Need wiring diagram/info for wiring 30 amp cord to 50 amp female marine plug

[57chevyconvt]

I have a 30 amp cord that has a 50 amp female marine plug that is for some reason causing a GF once it is plugged into the RV. I have been using this extension cord for about a year without any problem. Just arrived in Florida RV park and when I plugged the cord into the RV is when I got the GF readout, plus the voltage went low when running the micro wave or water heater. Inspect of the wiring at the 50 amp female plug as following; white wire is connected to the ground (grn), green wire connected to the white wire location noted on the plug. The black cord wire is connect to both the hot connectors. It appears to me that green and white wire are crossed, but the strange thing about this 30 to 50 amp. cord is that it has worked OK up until now. I also plugged a 50 amp to 30 amp adaptor into the Park Post to check to see if the 30 amp outlet was miswired, same results, i.e., GF and low voltage when turning on heavy loads. Park maintenance tech check out his end and the post wiring and voltage is correct.

To solve the immediate problem, I used the 50 amp. cord that came with the trailer and everything works just fine. The reason for using the 30 amp cord is the weight and ease of handling. Since I don't have the second A/C unit, I don't need the 50 amp. cord to run the RV.

Have been looking on the Internet for some help in locating a wiring diagram to help me trouble shoot the problem, no luck thus far on finding the wiring information needed. Any and all help will be much appreciated.

 

[cookie]

I agree that it sounds the wiring of your plug is wrong. But if it has been working in the past I wonder why not now and the only thing I can think of is if the park pedistal has an open ground. I have found this to be a problem at a few RV parks.
Do you know what the park maintenance guy checked other than voltage and a visual check of the wiring?
Also, do you use any type of protection such as a Progressive EMS that would tell you what the probem is?
Don't rely on any of my electrical information to be correct. I am not an elektrishion.......I don't even know how to spell it.

Peace
Dave

 

[Ray LeTourneau]

Jim, keep in mind that when running on 30amp, using the electric side of the hot water heater and the electric side of the reefer can consume quite a bit of your 30 available amps. Add the microwave, a coffee pot and the A/C and you might be in for a popped breaker at the pedestal.
I agree, the common and ground sound as if they're crossed on your adapter plug.

 

[branson4020]

#1 - correct the wiring in the cord. Reversed neutral-ground in the cord is not normally a problem, but if something is amiss with the park power, then the symptoms can be odd. Check that the green wire is really connected to the ground pin at the 30A end. If it is, then correct the miswiring in the 50A end.

#2 - don't believe the park technician. Use your multimeter and verify the voltages at the pedestal - 0V from neutral to ground, 120V from hot to neutral, 120V from hot to ground.

 

[57chevyconvt]

I have a 30 amp and a 50 amp Progressive portable EMS, both of which showed the RV post 30 and 50 amp plugs to be wired correctly at the parks post. As to the electrical consumption, when either the micro wave or the HW htr was in operation, neither in operation at the same time, the voltage dropped from 125 to 110 according to two separate 110 volt outlet metering devices, both indicated the low voltage and GF (ground fault). The park maintenance tech said the electrical meter was really spinning when I flipped on the HW htr. The park electrical system has been updated within the past year.

The strange thing about the 30 amp cord is that it has worked well in all the RV parks from Texas to Florida, up until we plugged into the electrical outlet at the current park where we are spending the month of December in Ft. Lauderdale. The process of elimination indicates that the problem is the 30 amp cord. ?????? The 50 amp cord is working very well.

 

[JohnDar]

You might also try putting your Ohmmeter on the 30A cord, itself. Make sure there is continuity between the ends for all of the wires in the cord. Have the wife manipulate the cord a bit as you test each wire. Through repeated use, there may be some damage to the internal insulation causing the fault.

 

[caissiel]

My 30 amp to 50 amp cord is wired this way.
Green connected on green. The white on white and the black is connected to the black connection and jumped to the red connection at the female in the plug. Mine is a special 30 amp to 50 amp style 2 line female 30 amp plug.
The white is always common and the black wire goes to both red and black 50 amp plug. It only can carry 30 amps combined on both legs. While the 50 amp cord can carry 50 amps on each line of the coach, for a total of 100 amps combined.
I also use the 30 amp cord at home and have found that the 30 amp female plugs on my extension will not carry 30 amp and will fail without kicking out the 30 amp fuse I have on my garage plug. Maybe the male plug has failed on your wire and the ground wire is getting cross power from the live wire causing a fault after heavy use.
Moisture also will cause female plugs to get wet and fail as I have to protect my connection at home. But you are not using an extention, and are direct to the post, or maybe your 50 to 30 amp female has failed, if you have to use one.

 

[57chevyconvt]

Laurent, Thought I would sent pictures of the 50 amp female plug that shows the wiring arrangement so that you can compare it to the wiring in your 50 amp plug. According to the 50 amp plug the wire location of the white and green wires are reversed. Having said that, I still is puzzling to me why this cord has worked well prior to now. I use the 30 - 50 amp cord at my home RV parking location without a problem. It is my understanding the neutral wire is only connected to the commond ground at the meter loop and no where esle. I use the Progressive EMS at home and at all RV parks. But of course the cord problem is down stream of the EMS device.

 

[porthole]

I use the Progressive EMS at home and at all RV parks. But of course the cord problem is down stream of the EMS device.

Well if Jamie is reading this - one more reason to hard wire the Progressive EMS in.

 

[57chevyconvt]

Duane - I agree that the Progressive hard wired unit is the way to go, had this on my last trailer. Bought the portable Progressive EMS units 30 and 50 amp off of Ebay at a very good price. I rewired the 30-50 amp cord yesterday and checked the rewire with Ohm meter as suggest by John B. I believe the reason for the GF problem was the miswire 50 amp female plug and the fact that this is the first time I have used this cord on a Park electrical post with a meter, all other usages have been in parks where the electrical power is included in the park fee without the use of a meter. Maybe someone with more deeper knowledge of electrical connections as to when and where the common wire is connected with the system ground.

 

[cookie]

Now that you have rewired the plug are you going to try out the 30 amp cord to check if the ground fault went away?
Inquiring minds want to know.....well at least I do.

Peace
Dave

 

[57chevyconvt]

Dave,
Prior to breaking camp here in Ft. Lauderdale early next month, I do plan to check out the 30 to 50 amp. cord. It is much easier to handle on our frequent stops for the return trips to Texas. At the moment, the DW is not in favor for giving up TV and A/C for my experimenting with the 30 amp cord. Well let you know the results in a few weeks.

 

[Willym]

I've seen a similar problem at a SOB rally. It turned out that the ground and neutral wire connections inside the trailer were reversed (since manufacture) and the pedestal had a high resistance ground connection. This caused a very low voltage across the load in the trailer whenever any load was turned on as the AC return path was via the bad ground. The owner said that this had never been a problem before. This was because he had been always been fortunate enough to plug into pedestals with good ground connections. When the wiring in the trailer was corrected, everything worked fine. The bad ground at the pedestal was repaired by the park. A bad or open ground at the pedestal compromises your safety should a fault develop in trailer causing a live wire to come into contact with what should be a grounded part. You could confirm a bad pedestal by checking the resistance between the pedestal neutral and pedestal ground.

 

[57chevyconvt]

Rewired the 50 amp plug by connecting common white wire to common terminal on plug and ground green wire to ground terminal on plug and all is well. The key learning here is not assume that everything is always wired correctly. I know that some folks are color blind when it comes to color coding wires.