Electrical problem

Make a simple and inexpensive tester as shown on myrv.us/electric. Click on Outlet Testing. Click on 50 Amp Outlet Tester. Parts available at home improvement stores.

The first thing I do when arriving at a new site is plug in the tester to verify voltage and correct wiring. Can be used with a 50-30 adapter to test a 30 amp outlet also.

An open neutral can cause some serious damage. The 240 volts between L1 and L2 now gets divided between any running items unevenly. High resistance items will see more voltage and lower resistance items will see low voltage. So your A/Cs could have been seeing 80 volts while your microwave was seeing 160. It all depends upon what was turned on at the time, and what was connected to each side of the panel. That is why it is important to check the power before plugging in, or having an EMS such as the ones from Progressive Industries which will disconnect your RV from power if something like this is wrong on the pedestal.

You might have permanent damage to items inside your RV now. You should check everything before you leave that campground. I'm not sure about who will have to pay to repair any damage that is caused by bad wiring in the pedestal. It would seem to be obvious that the campground is responsible, but who knows what is in the fine print on the agreement you signed when you registered.

Yes a loose or open neutral can cause you all kinds of problems.
One line will have low voltage the other line will have high voltage.
Both will add up to 240 volts.
I had this happen at a campground in Moab Utah.
It cost their insurance over $1600.00 to repair my Motorhome.
TV, Microwave, Converted and Refer all had to be repaired or replaced.

It is possible that the problem was caused by the broken neutral leg. It would take a thorough understanding of how your 50A 240vac supply line is hooked up to the transformer that is owned by the utility company. I'm not saying they (utility) caused the problem. The CG electrician found a loose neutral wire which (I said possibly) caused an unintended introduction of full 240 volts to all your 120 volts outlets thereby exposing your appliances to higher voltage than they are designed for. Having the loose wire repaired will not restore the normal function of your appliances.
As an analogy: you can't restore the normal function of an engine if you ran it without oil.

I carry this arrangement with me for testing the Camp Ground Pedestals...



I use one of these three position plug adapters as the 120V receptacle on the KILL-A-WATT P4400 meter is not all that well built.



All photos GOOGLE Images

This will plug into the 120V 20AMP Service plug just fine but if I want to test the 30A or 50A side of the Pedestal I have to use my RV30A or RV50A long adapters to get down to the 120VAC socket to plug in my setup here...

Has saved me a couple of times over the years...

Roy Ken

Even though I have a hard wired PI EMS HW 30 I always check with my home made pedestal checker,cheap but it works.

Saves me the hassel of dragging everything out.


I also use my 50amp to 30amp adapter to check the 50amp side. Sometimes I like them better as the are in better shape.

BB_TX wrote:
Make a simple and inexpensive tester as shown on myrv.us/electric. Click on Outlet Testing. Click on 50 Amp Outlet Tester. Parts available at home improvement stores.

The first thing I do when arriving at a new site is plug in the tester to verify voltage and correct wiring. Can be used with a 50-30 adapter to test a 30 amp outlet also.

Good site, thanks for sharing

Yes, neutral bad or open connection can cause serious problems.
I would write a note to the campground explaining the situation.
Explain that you will be sending a bill for your repairs.
Ask if their insurance company wants to send an adjuster out.
Any and all 120volt appliances can be damaged including your converter.

PS: Definately buy a Progressive Industries EMS. It will protect you from such damage in the future. Well worth the cost.

Call me if you like.

Moved from Forum Technical Support

It is good to have testers with you to check the power at pedestals. However, the readings would depend on what you would expect. Readings could be within normal limits as shown on the tester but this problem (loose neutral) could also happen in the coach, the extension cord or even the plug itself.
Anytime a 240 volt power is brought into the rig, there is this possibility--and consequently frying all your appliances.

This is the reason I don't want a 50A. With a 30A power feed, this can never happen because all you can get is strictly 120 volts. Others will not agree but the luxury of having a 240 volt that would run several appliances at the same time is an overkill in an RV. I would certainly enjoy all these niceties at home--not on the road.
Then again it's just me.