Bounder: Shore Power Trips Circuit

[hteixeira]

Hi Everyone,

I'm stressing out a "little" bit here. I have a 2003 Fleetwood Bounder 35R that has been great to us (second owners) the past 5 years. However, I am at a point where not only have I reached out for help, but I'm wondering if the professional I hired is confused as well.

Issue: Every time I try to plug into shore power at the house, I trip the circuit.
What I have done: I have tried GFI and non-GFI. Still trips instantly.
The 30 amp shore power cable head seemed to have had better days, so I rewired the head thinking there may have been a short (prongs wiggly as well). Still trips instantly. I'm not reading a short in the power shore cable to junction box (continuity present for ground, neutral and live wire).
With the unit UNPLUGGED, I start generator fine. All appliances work fine. Shedding system works fine - AC's, REFER, etc... all good. Ran for hours, no issue. I shut down the load, then shut down the generator. I then SHUT DOWN ALL BREAKERS at the motorhome breaker panel. Tried plugging into shore power, still trips instantly.

At this point, I called in for help. Reputable mobile RV repair guy came buy today. He fairly quickly and thoroughly narrowed it down to shore power line (post junction box) and into the breaker panel. His hunch is that there is a transfer switch issue, though he was not familiar with the transfer relay he saw. He suspected he was wrong when he saw the transfer relay delay box.

After reading the forums a bit, it's my understanding that the shore power line gets fed into the real auto transfer switch directly into the Power-tek PDC-3009 panel (behind the breakers) and the other box that he saw was a transfer relay for the air conditioner (15 amp transfer relay delay).

I've since called him and he's planning on coming back soon to do further tests after discussing with Fleetwood (not sure with who). I should add that part of his troubleshooting had the neutral disconnected from the panel and the circuit no longer tripped. There were plenty of other tests he did to pinpoint the issue....however, he was confused with the wiring so he paused to collect more information instead of just "replacing trial/error method".

I guess my long winded question is: Can a bad automatic transfer switch cause the shore power to completely trip a breaker?

I am very sorry for the long winded post. My mind is going a mile-a-minute.

[Ljwt330]

Here are my thoughts, worth the money you are paying for them.


Your description indicates the breaker trips as soon as the shore cord is plugged in. That indicates to me, assuming the cord itself is not the issue, that the first electrical connection in the coach that the cord reaches becomes your prime suspect. If that is your automatic transfer switch, that is the first thing to check. Typically, there is a delay between when the shore power is plugged in and the transfer switch activates. If the breaker tripped after the delay, that would indicate a problem with something in the coach wiring. Since there is no delay, I'd suspect a problem in the transfer switch itself, maybe the shore contactor if that's involved in the timed delay (don't know how that works.)

[twinboat]

Here is a theory, ignore if way off base.

Most 30 amp transfer switchs don't have a delay on shore power.
They are normally closed, meaning they stay connected to the shore cord unless generator power is sensed.

Since the RV works on generator power, and you metered the shore cord and found no shorts, I would look further down the line.

You may have switching gear for the 2 ACs. That switch doesn't select one AC or the other, when on generator power. The second generator output powers the second AC. But on shore power it does, so you can't run both.

If you have a Front/Rear AC selector switch, have you tried it in the opposite position ?
Try turning off the generator breakers before plugging in, as a test. A stuck relay may be back feeding.

[hteixeira]

Thanks ljwt330. That’s the approach he’s taking as well except for his uncertainty for behavior and where he thought the first electrical connection is at. I’m hoping this is resolved soon as I have a trip coming up next Thursday and it would be nice to plug in.

Twinboat, he looked further down as well but he can’t get past all of the breakers being in the OFF position, the power should never pass that point, I instantly trip.

I did go out and try your suggestion though of turning the circuits on the gen off (have 20 and 30a) and tried plugging in (with inside house breakers off as well) and instant trip.

Im sure once he ramps up on the powertek internals he’ll catch it.

Thanks

[Podivin]

If I'm understanding the test you did on the shore cord (continuity present for the 3 wires) there is another test I'd suggest you do. Check for continuity to the OTHER wires - which there should not be.
You've already tested to see if wire X has continuity, now you're testing to see if wire X has continuity with wire Y - in other words testing for a short inside the cable.
I'm wondering if none of the wires are broken and thus test OK, but two of them are touching somewhere along the way, causing the breaker to trip.

If at all possible, try rigging up a replacement shore cord, even just using a regular extension cord. I'm not suggesting this as a replacement, just use it long enough to see if the breaker trips when you plug it in.
Or for that matter, remove your current cord from the RV, secure the loose ends, and plug it in - what happens?

[tmw188]

Do you have a solid state board that plugs in under the two contactors looks like this?

[Alan_Hepburn]

You didn't mention so I'll ask: have you been plugging in to the same outlet with no problems and all of a sudden there's a problem, or is this the first time you're plugging in to that outlet? Have you tried plugging in to a different outlet?


If it's a brand new 30A outlet is it wired for 120V or 240V?

[vsheetz]

Sure sounds like a transfer switch issue. And yes, transfer switch can immediately trip shire power breaker.

Maybe move the shore power connection in place of the generator and see what happens.

[hteixeira]

Originally Posted by Podivin

If at all possible, try rigging up a replacement shore cord, even just using a regular extension cord. I'm not suggesting this as a replacement, just use it long enough to see if the breaker trips when you plug it in.
Or for that matter, remove your current cord from the RV, secure the loose ends, and plug it in - what happens?

I'll maybe give that a shot tomorrow if the rain holds off. I have a long 30a extension cord that I haven't used in 6 years, so maybe I'll cut the female end of that and hook it up the junction box. Other than killing an extension cord, it would certainly confirm the cord to the junction box - but I'm fairly certain the repair guy did something to confirm it. I might give him a call tomorrow to confirm before cutting up the cord.

[hteixeira]

Originally Posted by tmw188

Do you have a solid state board that plugs in under the two contactors looks like this? Attachment 206902 Attachment 206901

Sorry - That does not look familiar. I'll try to take a look tomorrow to identify something similar. What does that board control?

[hteixeira]

Originally Posted by vsheetz

Sure sounds like a transfer switch issue. And yes, transfer switch can immediately trip shire power breaker.

Maybe move the shore power connection in place of the generator and see what happens.

Thank you. Part of me is hoping for a transfer switch issue, though I am not sure how difficult it is to get that part now-a-days. Other part of me thinks that while a mouse chewed wire would be easier to replace from a part perspective, the amount of work to get into the wall is going to be lovely (ie, labor inten$ive)

[twinboat]

Originally Posted by tmw188

Do you have a solid state board that plugs in under the two contactors looks like this? Attachment 206902 Attachment 206901

That's a 50 amp ATS, the OP is 30 amp.

[twinboat]

Don't chop up a cord, use a cheap extension cord as a test. Wire it in place of the original cord and plug it in.

You only need hot, neutral, and ground. The gauge of the cord is irrelevant at this point, just don't try to run everything.

[hteixeira]

Originally Posted by twinboat

Don't chop up a cord, use a cheap extension cord as a test. Wire it in place of the original cord and plug it in.

You only need hot, neutral, and ground. The gauge of the cord is irrelevant at this point, just don't try to run everything.

Thank you! I’ll give that a shot. It’s starting to rain now so I will wait for it to pass.