Basic Question About AC Power Wiring

[HadEnough]

How are RVs usually wired up?

I have a standard arctic fox RV and I’m having trouble with the AC portion of the wiring.

Symptoms:

*After running an air conditioner for 4-5 hours, off an external generator connected to the shore power cable, I get a brownout” situation and the microwave turns on and off every second or two repeatedly during this brownout.

*Its getting worse. Sometimes I get the same thing on startup. Other times it randomly works great for hours and hours.

*when I use the onboard generator, it will either work great or it will have the same type of problem as the external. HOWEVER, when the external generator would have the brownout or cycling, the onboard generator is smarter and just shuts down.

*there seemed to be a VERY long delay tonight using the onboard generator before the power came on.


So far I’ve looked at the transfer switch. I opened it. Hard to see the contacts, but they didn’t really seem to do anything actually probably because I was on the shore power generator. And it was working fine.

So my question is related to diagnosis.

What components are involved?

What components are common to the shore power and the onboard generator such that they can cause brownouts, cycling on/off of power and the onboard generator to decide to shut down?

I’m looking hard at the automatic transfer switch but I don’t see any problem.

It seemed to get better a bit when I exercised the main breaker on the panel, but it’s intermittent and that may not even be it.

What components are there to check?

[enblethen]

Most transfer switches only uses logic on the auxiliary power supply. The OP uses shore power to feed rig from portable gensets. Transfer switch logic would also not cause brown out type issue. only thing in transfer switch that could cause problem is contacts.

[time2roll]

I find it odd to be the transfer switch since both the utility cord and on-board generator have the same issue.

Maybe start with isolating some circuits like setting the fridge and water heater to propane only.

[3_tons]

Dusty R wrote:
I've never seen that type of problem with a breaker. I've seen breakers that would not reset, And once seen one that would not carry the load it was rated for. I've also seen where they were turn on and off every day switching lights in a commercial/factory work/wear loose and heat up.
Stop up my way and I'll take a look at it.

Dusty

I only mentioned the breaker since it is a mechanical-magnetic device - the ATS could still be suspect, whether the contacts, coil or faulty logic board...Bypassing is the ticket!

HadEnough is doing some mighty fine sleuth work!!

3 tons

[Dusty_R]

I've never seen that type of problem with a breaker. I've seen breakers that would not reset, And once seen one that would not carry the load it was rated for. I've also seen where they were turn on and off every day switching lights in a commercial/factory work/wear loose and heat up.
Stop up my way and I'll take a look at it.

Dusty

[time2roll]

HadEnough wrote:
I was able to get 1/2 or 1/4 turn on a couple neutrals and hots in the circuit branches.

All wires to and from the ATS were securely connected inside.

Unfortunately, I’m guessing I’m down to eliminating components at this point.

I thought you might find some heat discoloration while tightening these various connections.

Intermittent problems can be challenging. How long do these episodes last?

[pianotuna]

HadEnough,

Particularly if the transfer switch has been cycled when under large loads.

[HadEnough]

3 tons wrote:

enblethen wrote:
If your transfer switch is readily accessible, you might try connecting your shore power cord wires directly to the wires going to the distribution panel using wire nuts. The using portable genset see what happens.
By doing this to take the transfer switch out of the equation.
By passing was suggested by others,

X2

“Unfortunately, I’m guessing I’m down to eliminating components at this point.”

Since it happens with either genny I would doubt it’s the shore power cord. Do not dismiss connections at the main panel and the possibility of a defective main breaker...

3 tons

Ok. That’s what my post was originally about. I asked how the wiring went coming into an RV typically. . Main panel? I just have power coming into a circuit breaker panel. That panel has a main breaker which may or may not be bad.

I tightened and checked every AC connection on the panel. And on the ATS.

Everything looks like it wires directly to the ATS first. No main panel. Just the one panel.

I’m down to isolating components and the ATS is the first one I need to do.

[3_tons]

enblethen wrote:
If your transfer switch is readily accessible, you might try connecting your shore power cord wires directly to the wires going to the distribution panel using wire nuts. The using portable genset see what happens.
By doing this to take the transfer switch out of the equation.
By passing was suggested by others,

X2

“Unfortunately, I’m guessing I’m down to eliminating components at this point.”

Since it happens with either genny I would doubt it’s the shore power cord. Do not dismiss connections at the main panel and the possibility of a defective main breaker...

3 tons

[enblethen]

If your transfer switch is readily accessible, you might try connecting your shore power cord wires directly to the wires going to the distribution panel using wire nuts. The using portable genset see what happens.
By doing this to take the transfer switch out of the equation.
By passing was suggested by others,

[HadEnough]

Exploratory done.

No results.

All wires to ATS and breaker panel tightened, paying special attention to neutral.

None of the main supply lines were loose at all.

I was able to get 1/2 or 1/4 turn on a couple neutrals and hots in the circuit branches.

All wires to and from the ATS were securely connected inside.

I scraped the connectors inside the ATS a little bit to see if maybe they had some corrosion.

Unfortunately, I’m guessing I’m down to eliminating components at this point.

[HadEnough]

wa8yxm wrote:

HadEnough wrote:
How would that be possible when the behavior happens with the air conditioner OFF???

AGAIN, IT’S AN ELECTRICAL PROBLEM

My Mistake, Thought he said it happend with Air Conditinoer on.

Ok true story time
Now in my case it was the A/C's (50 amp rig 2 of them) sometimes one worked, sometimes the other, both or neither.

First stop on the tribble search was the power distribution panel (Breaker box) also, as it turned out, the last stop.

The wires clamp to the bus bars and to the breakers with screws. One of 'em took over THREE FULL TURNS before I Called it tight.

The result of this is I have a saying:
Many RVers have a few screws loose
And no you know EXACTLY what Screws I'm speaking of.

Mine took either a #2 Phillips or Square (Also #2) square worked best

As my favorite RV-Girl (That's the license plate on her work van) says "When I tighten them they don't come loose" (We think alike on many repair jobs).

Excellent! My first stop because it’s so easy.

Sorry to have been short with you. Up thread I had just got done saying it was an electrical problem a couple times.

[wa8yxm]

wa8yxm wrote:

HadEnough wrote:
How would that be possible when the behavior happens with the air conditioner OFF???

AGAIN, IT’S AN ELECTRICAL PROBLEM

My Mistake, Thought he said it happend with Air Conditinoer on.

Ok true story time
Now in my case it was the A/C's (50 amp rig 2 of them) sometimes one worked, sometimes the other, both or neither.

First stop on the tribble search was the power distribution panel (Breaker box) also, as it turned out, the last stop.

The wires clamp to the bus bars and to the breakers with screws. One of 'em took over THREE FULL TURNS before I Called it tight.

The result of this is I have a saying:
Many RVers have a few screws loose
And no you know EXACTLY what Screws I'm speaking of.

Mine took either a #2 Phillips or Square (Also #2) square worked best

As my favorite RV-Girl (That's the license plate on her work van) says "When I tighten them they don't come loose" (We think alike on many repair jobs).

NOTE Of CAUTION
when you check those screws.
Unplug (from shore or portable generator) TURN OFF on board, NO 120 volts 12 is OK (Battery) and a flashlight if needed.

[wa8yxm]

HadEnough wrote:
How would that be possible when the behavior happens with the air conditioner OFF???

AGAIN, IT’S AN ELECTRICAL PROBLEM

My Mistake, Thought he said it happend with Air Conditinoer on.

Ok true story time
Now in my case it was the A/C's (50 amp rig 2 of them) sometimes one worked, sometimes the other, both or neither.

First stop on the tribble search was the power distribution panel (Breaker box) also, as it turned out, the last stop.

The wires clamp to the bus bars and to the breakers with screws. One of 'em took over THREE FULL TURNS before I Called it tight.

The result of this is I have a saying:
Many RVers have a few screws loose
And no you know EXACTLY what Screws I'm speaking of.

Mine took either a #2 Phillips or Square (Also #2) square worked best

As my favorite RV-Girl (That's the license plate on her work van) says "When I tighten them they don't come loose" (We think alike on many repair jobs).

[pianotuna]

To trouble shoot

bypass transfer switch



Next time there is an issue when running on the external genny, plug in a heater and then test voltage at the portable generator, then inside the RV.

You may also wish to switch from one generator to the other next time there is an issue.

My bet is on the transfer switch. I'd eliminate it and just use plugs.

[HTElectrical]

HadEnough wrote:

HTElectrical wrote:
You could also eliminate the transfer switch by connecting power directly to your electrical panel and see if the issue is still there. Check to make sure your Neutral connection is tight, breaker is not shorting out where it snaps onto bus bar, and also lug where your 120v line connects at bus bar is tight.

Definitely. Thank you. I’m going to work through this ASAP on a cool morning. Maybe tomorrow

The simplest thin to check is the connections in your panel. Make sure both main lugs are tight, make sure connection on main breaker (if you have one) is tight, and look at bus bar where breaker snaps onto it is not burned. If all of that looks good, then move onto ATS and also check your plug and receptacle for your 30A cord.