Open neutral

Is your shore power cable or plug damaged in any way?

Are you using a surge protector that plugs into an outlet in the RV to protect individual devices? Or a surge protector that plugs into your shore power outlet to protect the whole RV?

Make and model of the converter may be helpful.

enblethen wrote:
You are mixing up a converter with an inverter!
A converter changes 120AC power to 12-volt DC.
An inverter changes 12_volts DC to 120-volt AC power.
Your surge protector is telling you that the power between the rig and shore power source has an open neutral.
Are you using an adapter?
Are you connecting to 30, 50 or 15/20 shore power?

Assuming that you ARE using a converter and the power post is confirmed good and the surge protector is reporting an open ground, then the problem is between the post and the surge protector.

Inverter makes 120 volt out of 12 volt
Converter makes 12 volt out of 120 volt

Many inverters have and optional "Bonding" feature (or none at all)
If the bonding feature is set to "not bonded" (Often it's a screw that fits in one of two holes) then you have an open neutral when the inverter is in operation.

If the neutral is not properly connected to the green wire/screws on the inverter.... It really messes things up.

Larger inverters often contain a transfer switch.. With shore power... All 3 leads "Pass through" so bonding is done at the service master (park in this case) as code requires.. But when operating on "Inverter" (Battery power) it's up to the bonding setting. NOTE not all inverters have this.

But you said when on inverter you only get 100 Volts... MSW inverters will often read low on a "Peak reading" volt meter.. Most low cost volt meters are Peak Reading... (I have some True RMS types the MSRP on them (not what I paid) is over 200 dollars.. (Got 'em at a "Fire Sale"for less than half).

For more detailed reply I'd need make and model of the Inverter and/or eyes on.

Skyhow1 wrote:
So I had an electrician come out and test the pedestal and the cord and all works as it should.

OK but what about the wiring from the cord to the EMS and inverter?

Skyhow1 wrote:
So I had an electrician come out and test the pedestal and the cord and all works as it should. When the converter is disconnected the surge protector reads good and everything in the camper works fine and all breakers read good. I have 30 amp plugged in straight with no adapter.

It's also possible that the problem is related to the load.

A reasonable good test is to use a 30/20 adapter, plug in voltmeter, 3 light household test, then a small load and then a large load like a ceramic heater.

Have you (or prior owner) by any change installed an inverter that does not bond it's output AC neutral and ground? Where are you detecting the open ground? At a EMS or plug?

There are also combined charger/inverters, and these units also require AC input.

Converter is also a slang term for charger or battery charger.

Maybe this helps:


Pedestal>EMS>CB Panel>charger/inverter>some outlets and other variations.

Normally a "surge protector" ie EMS indicating open ground is before the inverter and hence can cause down stream issues.

So I had an electrician come out and test the pedestal and the cord and all works as it should. When the converter is disconnected the surge protector reads good and everything in the camper works fine and all breakers read good. I have 30 amp plugged in straight with no adapter.