Power keeps cutting off then coming back on - no tripped circuits

[RichK]

Question - is it unusual to get a different voltage reading from hot to ground than from hot to neutral? (Inside the RV).

I tested today - 122.4 hot to neutral, and 120.7 hot to ground in an outlet inside the RV. Might that mean a slight issue with a ground connection, or is that normal?

Maybe they use smaller gauge wiring for ground and that explains the difference?

[Dr4Film]

Sometimes the ground is a smaller gauge wire than whats used for the load and neutral.

Dr4Film ----- Richard

[TQ60]

That is indicating out of balance load which may be fine but it could make an EMS nuts.

The neutral carries the difference current between L1 and L2.

If there is more L1 than L2 then current will flow in neutral.

There should never be current flow in safety ground.

If there is a bad neutral connection someplace and the correct loads in the correct place it could make your ems nuts but I do not know if the ems is looking at that unless a 50 amp coach.

And it could be in the campground someplace and just happens when stars line up...

Measure between safety ground and neutral and see how high of a voltage you can measure and follow up with ems manufacturer to see if it reacts as yours does.

It may be you are golden and campgrounds bad.

We had squirrels chew up our neutral in the overhead drop and the large machines (240vac) were fine but light bulbs went real funny as they were 120 vac and created unbalanced loads.

Ours was open connection so lightbulb had effect but a poor connection requires more load.

[Old Bounder]

Originally Posted by TQ60

That is indicating out of balance load which may be fine but it could make an EMS nuts.
The neutral carries the difference current between L1 and L2.
If there is more L1 than L2 then current will flow in neutral.
There should never be current flow in safety ground.
If there is a bad neutral connection someplace and the correct loads in the correct place it could make your ems nuts but I do not know if the ems is looking at that unless a 50 amp coach.
And it could be in the campground someplace and just happens when stars line up...
Measure between safety ground and neutral and see how high of a voltage you can measure and follow up with ems manufacturer to see if it reacts as yours does.
It may be you are golden and campgrounds bad.
We had squirrels chew up our neutral in the overhead drop and the large machines (240vac) were fine but light bulbs went real funny as they were 120 vac and created unbalanced loads.
Ours was open connection so lightbulb had effect but a poor connection requires more load.

I think this is a 30amp coach we have been discussing. No balancing currents involved.

[Old Bounder]

Originally Posted by RichK

Question - is it unusual to get a different voltage reading from hot to ground than from hot to neutral? (Inside the RV).

I tested today - 122.4 hot to neutral, and 120.7 hot to ground in an outlet inside the RV. Might that mean a slight issue with a ground connection, or is that normal?

Maybe they use smaller gauge wiring for ground and that explains the difference?

Not entirely unusual in a motorhome. The ground and neutral are tied together back in the shore supply somewhere, but your working voltage is between Hot and Neutral. Depending on where you are taking the measurements, there could be many more feet of wire involved in that measurement. It's nothing to be concerned about.

[TQ60]

30 amp coach so no balance issue with coach but campground is 240.

So possible...there was another thread regarding this and the voltage between safety ground and neutral was in question but not confirmed the max allowed under NEC.

[Old Bounder]

Originally Posted by TQ60

30 amp coach so no balance issue with coach but campground is 240.

So possible...there was another thread regarding this and the voltage between safety ground and neutral was in question but not confirmed the max allowed under NEC.

As I read this thread, there have been multiple different campground systems involved where this failure was experienced.

Something in the path, from external power cord plug to transfer switch contacts, is not playing nice in this RV.

[nothermark]

Where are ground and neutral tied together? I would assume it would be the outlet box just from seeing grounding rods at the installations I remember. That would also require one of the common blocks at the distribution panel in the MH be floating. I wonder if there is a problem there.

[Old Bounder]

Originally Posted by nothermark

Where are ground and neutral tied together? I would assume it would be the outlet box just from seeing grounding rods at the installations I remember. That would also require one of the common blocks at the distribution panel in the MH be floating. I wonder if there is a problem there.

There is nothing in that scenario that would cause the recorded symptoms.

Bonding the neutral and ground in the RV Distribution Panel usually does not cause an operational problem, but does present a potential safety concern. By code, the RV panel should be wired just as a sub panel in a S/B.

[Dr4Film]

Correct!

RV Pedestals should have the ground and neutral separated and not bonded.

The bonding should only be done at the main supply panel and not at any sub-panels.

Dr4Film ----- Richard

[RichK]

I think I've found the problem! I did as suggested, and ran the Generator, ran things on the generator, etc.. Put it back to park power, tried running the Microwave and BAM power went out.

My EMS NEVER lost power - the readout showed 123V the entire time.

So I have a bad transfer switch, right? I have a Parallax Power Supply ATS 301 FYI.

Yes, I had the cover off the transfer switch - power was coming in 122.4V, and no power was coming out for a couple minutes.

Should I try cleaning all the contacts and wires? Or is the Transfer switch bad?

Thanks again for everyone's help!

[Dr4Film]

OK....Take a look at the ESCO ATS LPTBRD.

I prefer this model over others. Mine has been working FULL-TIME since 2001 without a glitch.

Dr4Film ----- Richard

[Old Bounder]

Originally Posted by RichK

Should I try cleaning all the contacts and wires? Or is the Transfer switch bad?

Thanks again for everyone's help!

Absolutely you can try cleaning the contacts. Unplug from shore power and clean the Normally Closed contacts on the power contactor.

A few swipes through the contacts with very fine emery cloth should do it.

AS Richard suggested, a new ATS may be in your future. IOTA also makes a very reliable (and much less expensive) ATS.

[RichK]

Originally Posted by Old Bounder

Absolutely you can try cleaning the contacts. Unplug from shore power and clean the Normally Closed contacts on the power contactor.

A few swipes through the contacts with very fine emery cloth should do it.

AS Richard suggested, a new ATS may be in your future. IOTA also makes a very reliable (and much less expensive) ATS.

Will do (try cleaning). It looks like IOTA no longer makes transfer switches? I looked online and can't find any for sale.