Electrical problem. Probably expensive.

[Adam Hicklin]

Mike, I’m not exactly sure although I know a grounding wire can be one size smaller than the hot and neutral in residential wiring, but this looks to be 2 sizes smaller.  All that wiring (transfer switch included) is original coach wiring.  The wiring from the transfer switch to the load side, I added.  All wires 6awg. 

[Adam Hicklin]

New update.  Installed the new SurgeGuard.  Powered everything up and much to my surprise, everything worked (almost). This is surprising because at least one outlet I tested, before I realized what was going on, had 240V.  Surprisingly, nothing fried.  All electronics work.  Microwave works.  All is normal.  Except one thing... on the Coach Monitor Panel the Leg 1 and Leg 2 voltage read “off” even though there is full voltage coming in to the coach. All other CMP functions work and are correct. 

Any ideas?

[Fred Brooks]

   Adam,
   Where did you measure the 240 volts at. Did I understand you correctly that it was at an electrical outlet and if so was it between the neutral and the hot? The CMT gets its info from a module somewhere near the electrical breaker box not sure exactly where.

[Bill Lampkin]

There is only one way to obtain a 230v reading on our RVs and that is to measure between two hot legs. If any receptacle measures 230v, you have a neutral crossed with a hot and you are looking at big trouble. Unplug from shore power and figure it out.

[Bill Lampkin]

Adam, I think you have an incorrect reading when you get 230v at your outlet. if that were the case, anything plugged into that circuit would be fried. Sometimes simple is better as far as measuring AC voltage. In the trade, we used a 'Wiggy' to test for AC. Its a simple solenoid device that buzzes and lights up when AC is present. Foolproof. Here's one, there are other less pricy units out there that do the same thing.

https://www.amazon.com/Knopp-K-60-Cat-Number-14460/dp/B003A7T5KG/ref=pd_lpo_469_img_2/141-6949460-2459362?_encoding=UTF8&pd_rd_i=B003A7T5KG&pd_rd_r=4c340a2f-ea46-477a-87c5-afe13fd36552&pd_rd_w=YoVz2&pd_rd_wg=hHwz6&pf_rd_p=7b36d496-f366-4631-94d3-61b87b52511b&pf_rd_r=08HJDT5KNZ2F70BPDTZ5&psc=1&refRID=08HJDT5KNZ2F70BPDTZ5

[Joel Ashley]

As Bill pointed out, you should only get 240 volts when one test probe is in each of the two “hot” ports.  Double check that this is the case at the park post outlet.  120v between either “hot” port and the neutral port.  Each “hot” represents a “Leg”, ie. L1 & L2.

[Adam Hicklin]

Fred, I’ll try to take a picture of where I THINK the CMP reads the voltage. 

Bil, yes, that happened when when the SurgeGuard had a loose connection and burned up the neutral. Not exactly sure what happened internally to combine the voltage but it happened on a non-inverter circuit, so I think that’s ultimately what saved me. And nothing was plugged in to that circuit. But in all honesty, I’m not exactly sure what happened because as soon as I realized something was wrong I shut it all down and replaced the obvious failure...the SurgeGuard.

[Eric Maclean]

Adam
If I understand properly you only had 240 volts at the outlets when the neutral or common wire was faulty and that with the new surge guard installed all is fine.
The reason you had 240 volts at the outlet without the neutral is that without the neutral for a return the power fed to any large low resistance load like your inverter charger or a heating element  will feed through the load to the neutral side making the neutral buss bar in the panel hot from the leg which feeds that load therefore when you checked the voltage at a receptical fed from the other leg you would effectively be reading the voltage between both incoming legs
When you restored the neutral connection the voltage at those recepticals should be back to 120 volts
I hope this is not too confusing
Hope this helps
Eric