Onan 7500 QD - Add a 30amp plug for trailer

[bjboles]

How would one add a 30amp outlet to the coach so I could run my race car trailer off the generator. It has a 13.5K roof mount AC. Another possibility would be to just add the Micro-Air EasyStart 364 to the trailer AC and run the trailer off of a 110 plug. There's a 110v outlet in the power cord bay of our Journey. Thoughts?

[Morich]

Interesting idea and seems to be somewhat simple with two options.
If one can get to the transfer switch and find it has room, etc. one could go there and pick up the power from the genset coming into the transfer switch as I've snip from this drawing:
https://www.winnebago.com/Files/File...ire_144991.pdf

Page five and option 670 for your size gen. One could go to the points marked in green but be aware there is only the generator breaker protecting you at that point.

OR one could chase out the power coming back from the load center (marked blue)after the transfer switch has done the decision of using genset power or shore power and tap into the cable with an outlet? This would give you the breakers at the load center as well as at the genset.
One could then use either shore power for the RV to get to the new plug or genset power.

Click the picture to get better view of it or go to the drawing?

I might look at which was more workable from a space, etc. view.

[imnprsd]

This week I added a GE 8,000 BTU Portable AC I bought at Lowes for $349. I hid it inside a cabinet and cut a hole in my passenger side wall to vent the exhaust.

I'm still "tooting my horn" over this upgrade, so please excuse the extraneous information.

For more information go to:

https://www.winnieowners.com/forums/...ad-360836.html

As to your concerns about tapping into your ATS, here's how I did it, and why I tapped into Circuit #2 (Black wire).

I.e., by tapping in to Circuit #2 (black wire) I now how have a better load balanced system on l1 & L2, and this is supposed to be better when I'm running the generator. Not to mention the following...

...Most everything in your RV is on Circuit #1, and your EMS is there to ONLY shed loads in your Main Power Panel. I.e., it has no monitoring or control over the CBs in the Sub-Panel (aka Inverter Panel).

And since I will never run my AC on my Dimensions inverter, since it's not a PSW inverter, I would prefer to wire the Portable AC to Circuit #2... and not use the existing outlet in the RV, even though that is a very convenient power source that is already there in my RV.

* Take a look at your Inverter Power Panel, and you will see all your wall sockets (Recpicles 1-3) and your microwave are in there and all these are on Circuit #1 (Red Wire to the Main Panel).

Specifically, I do NOT want the portable AC to add 8A to Circuit #1, because if I do I will be running in the 28A-29A all the time; and when I run my microwave the current will be in the 38A range, which is too high IMO.

Why is this important if I have 50A service? IMO, I think it is not a good idea to run more than 28A-29A for an extended amount of time (say 2 hours +). Why?

If you read your ATS-5070 manual it will tell you should not run more than 80% after 2 hours of operation, and they give a 32A example as the maximum current to start with.

So with a Parallax ATS-5070, that was designed for use with an Onan 7500/8000, they-Parallax, are saying 24-25A is maximum current you should operate there ATS over 2-hours of time. I.e, when you are running your ACs.

Note: Newer ATS 50A-Service boxes are now being shipped with 40A Contactors and these are even more prone to burning up with loads above 24A nominal and 20A over time. Which is just barely enough to run 2 AC on a generator an a residential refrigerator.

So I would not buy an ATS that uses Contactors in side, even when they say it is for 50A-Service, because being able to plug into 50A-Service DOES NOT mean you can run heavy loads, as I have just explained.

So, if your old ATS-5070 relays quits working, IMO, then I would order some new Deltrol Control Relays and get it rebuilt for $200 vs. buying newer designed ATS box that is sub-standard.

Note: Our Onan 7500 and Onan 8000 owners need a 7OA neutral capability and these newer ATS boxes DO NOT provide that, with the exception of Parallax 501 or 503. But I would only buy the 503 if you run your ACs a lot on generator power and want to run some other AC appliances.

=== GETTING BACK TO THE OP'S QUESTION ===

2 days ago, I just added an outlet to my ATS-5070 so I can plug in a 50-foot, 14A extension cord to power my portable AC (rated at 8A); and I see no reason why you can't do the same... so you can run on generator power with better "load balancing."

And then, when you have shore power, all you have to do is unplug the extension cord and add another expansion cord so you can draw power off the 20A or the 30A shore power line (using an adapter).

This way, your portable AC, or what ever you want to run in your trailer, will be on Circuit #2 when on generator power, and you have the option of running a separate shore power cord... which will not burden your ATS at all.

Can I presume you want to mount an AC in your Trailer?

[Morich]

I read it as he pulls a race car trailer with an air conditioner behind his motorhome and goes to tracks where he doesn't have AC power. So to use the air conditioner in the race car trailer, he wants a place to plug the 30 amp cord from this trailer into the RV to pick up power from the existing RV generator.

So looking /debating a handy spot to place a receptacle to plug the trailer into and that is on the output of the RV generator. If he had the old "Manual transfer" where we move the cord from the generator output box when we use shore power, he would already having an existing outlet but with the automatic transfer switch he is lacking the easy step and needs to add the outlet.

To me the bigger question is finding the easy spot for space and ease of getting wired from the generator.

[bjboles]

Morich is correct.

[imnprsd]

I'm doing the same thing by adding a portable AC, aren't I?

My manual transfer switch is "me" unplugging the portable AC extension cord from the ATS cover plate outlet I modified, and then just adding another extension cord for shore power service.

...And when I want generator power to Circuit #2 I just plug the AC extension cord into the modified ATS-5070 cover as shown in the picture above.

...If you are just powering-up and 8A-12A AC and nothing else, then why not just run 12 or 14 gauge extension cord back to the trailer when you need it... and are parked?

Of course, the longer the run... the thicker the extension cord, but 12 gauge should be plenty to handle an AC load in the trailer and the heat outside.

If you wanted to add a second ATS you can pick up a relatively cheap 30A ATS on Amazon by Go-power.

[bjboles]

Yes, I'm parked. I'm not sure I can get away with just a 15amp receptacle for powering up the trailer's 13.5k rooftop AC. Don't they draw over 20amps on initial startup?

[imnprsd]

My basement AC "in-rush" current is more like 47A, but it only lasts for a split second. Consequently, it does not produce enough heat to trip the 30A breaker in my RV when on shore power; and my Onan 7500 generator is rated for 63A.

What size generator do you have?

When Class "C" RVs have an AC starting problem it's becuase they come with 5000W generators; and these owners often solve that problem by putting in a $350 "Soft Start Kit".

These soft start kits are good, but I think $350 is a lot you may not have to spend at all.

First, you need to just try power up your trailer AC with a 14 gauge 50' extension cord and see what happens? ...And if you pop a breaker on shore power, then you need to run the test again with a 12 gauge 50' extension cord.

Remember, CB may be rated in amps, but they are really thermal safety switches.

After verifying shore power use, do the test using generator power and just plug the extension cord into a 15A coach outlet to test.

If you still have a problem, then you might inspect your trailer AC to see what kind of Hard Start Kit it comes with? ...Or if it does not come with one at all.

If this is the case, just add a HSK in parallel. Some people use an SPP6. Note: If your roof top AC did not come with a HSK, then your AC manufacture was too cheap to put one in, but you can do that yourself for $25.

... but I don't think you have to go to any of these lengths so long as you have a Onan 7500/8000 or bigger generator.

For more information on how to improve your AC starting circuit, or if you have a weak compressor and want to get some more life out it, before you "Schmitt-can" your AC, then you might want to search for my other threads on adding hard start kits under my user name.

Here's a link to an owner with roof top AC short cycling problem. This may help you understand how your AC will function, and your roof top AC may use a smaller HSK than my basement AC. (TBD)

https://www.winnieowners.com/forums/...ng-358155.html

IMPORTANT

When you tap into your ATS like I am, the only CB protecting that outlet is the 50A CB on shore power or the 35A neutral return breaker on my Onan 7500.

So one could argue that I should put a 15A breaker in line with my portable AC, and I just may do that. Remember the 14 gauge is supposed to be protected by a 15A breaker and the 12 gauge wire goes with 20A breaker.

[imnprsd]

I now see the OP has that same generator as me... And after much consideration I wanted my portable AC to be on Circuit #2 for better generator load balancing.

Below is a pictures of a 15A Push-To-Reset 120V Circuit Breaker that I will install next to my outlet I cut into my ATS-5070 cover plate.

Note: I suppose I could have cut-in a Ground Fault Breaker. But I am more concerned with heat from over-current than I am from getting shocked. ...But maybe someone can tell me if a ground fault breaker would be better to use in this application vs. a reset 15A breaker.

I do know, that motors, like a garbage disposal in a home, can trip a ground fault switch, but don't know if starting an AC with some amount of "in rush" current will trip a ground fault switch too?

[bjboles]

Thank you very much. Can you walk me through in detail (pics help) on how you wired the outlet to your ATS? This looks to be the best solution!.

[bjboles]

Also, I can get a 50' 10gauge extension cord. Would I still need a CB?

[Podivin]

Originally Posted by bjboles

Yes, I'm parked. I'm not sure I can get away with just a 15amp receptacle for powering up the trailer's 13.5k rooftop AC. Don't they draw over 20amps on initial startup?

I run my RV air conditioners plugged at the house, so yes they will for sure run on 15 amps.
FIRST thing I would do in your place is simply use a 15 to 30 amp 'dogbone' adapter on the external or basement outlet that I assume your RV has. Then plug the 30 amp from the trailer into the adapter and turn on the air conditioner with NOTHING else running in the RV. That's the easiest and cheapest way to see if you can run the AC off the RV. If it works then all you have to do is figure out what else in the RV is on the same circuit so that you know not to run those things when the trailer AC is running.
At worst you trip the breaker in the RV. At best you have a nice easy and inexpensive way to get power back to the trailer.
If you really want to add a specific 30 amp outlet for the trailer then I'd go for connecting in at the transfer switch as suggested above. Personally I'd attached to the 'out' side of the transfer switch, that way your new plug works on either shore power or generator. If you go this route you'll still need to know what is sharing power with the trailer, so you know which things you can run at the same time.

[imnprsd]

OP: When deciding on how to wire your trailer AC you want to separate shore power use from generator use.

You can run a long 30A cord, but it's more expensive, heavy, takes more room to store... you still have the problem of wiring it so your generator can provide power.
So don't go that route.

* 12 gauge romex would work, but it's not flexible and it's more expensive than buying an extension cord which already has your 15A/20A male and female plugs.

POWER CONSIDERATIONS

* Sometimes when you plug your RV into your house wiring, people don't know if they are using a 15A outlet or a 20A let. They only know if it works or not.

* The CB in the house (and RV) are cheaply made thermal switches and a so called "weak 15A breaker" may trip at 13A. ...Worse is it it never trips at all.

* CBs are there to protect the wiring... from turning into a heating element and catching on fire. They are not there to protect you from getting electrocuted. A ground fault CB is better for that.

* Fortunately, in the USA we use 120V, but most everywhere else they use 208V and that stuff will kill you. (Same goes for your 220-Dryer in your house, but the principles are the same.

* When you run a long (25,50, 100') extension cord, you will want to use a thicker gauge wire for the same amount of Amps/load (10A+ I would say is conservative).

* Your roof AC will probably run at 12A after it starts, but you should check to verify it is not 14A, which is too close to the 15A CB, IMO, but you can try it and see what happens after 4 hours of continuous use. And if it is not okay for continuous operation, then 12 gauge extension cord.

* Truth is, people use what they have first and worry about the consequences...like a tripped CB is no worry, so long as it trips!

* Your RV ACs have CB protection. But when you mount an AC on top of your trailer, your protection comes from what ever you plug into. (House, short power panel, RV outlet.)

* Everything has a margin of error (+ or -).

* It's when you are at the race track, and you are only running off your generator, then you may want to do what I just did. You want to build a Circuit #2 outlet and add a 15A CB with 14 gauge wire (extension cord) or use a 20A CB with 12 gauge.

Note: You can use a 15A CB with 12 gauge extension cord, and if you are using more than 25" of extension cord, then that is what I would do if you AC is pulling 12-13A.

At 14A with 25-50' of extension cord, I would use a 20A CB and 12 gauge extension cord.

* The reason for creating an outlet that runs off Circuit #2
I already explained. See "load balancing" discussion in previous posts.

* Reminder: Your Onan 7500 also produces L1=50A and L2=50A, like shore power, but it is single phase, and your generator has 2 neutral wires protected by 35A breakers ... which are mounted on your generator.

* When I have shore power, I really don't care if I have my portable AC on Circuit #1, but then all my ACs will put me at 28A-29A, and you better turn your battery charge down to 5A.

... but that's too much load on Circuit #1 (IMO) if you also want to run your microwave on Circuit #1, which will put you in the 38A-40A range... and I do NOT want that... even if the microwave is only running for 2-5 minutes.

Why? ...For one thing your AST will not like it; and for another your generator will not like it.

* When you cut into your Parallax ATS-5070 like I am, the 14 gauge (50') extension cord I am going to use is only powering my 8A portable AC.

...But there is no CB protecting the extension cord except the 50A breaker on shore power; or the 35A breaker on generator power.

...THIS IS A PROBLEM if your 14 gauge extension cord gets a sort or if the AC malfunctions (very unlikely), but the point is still the same... without a 15A CB protecting the 50' 14 gauge extension cord, the RV can catch on fire.

* RV AC do trip 20A breakers all the time, because they are cheaply made and poorly maintained. But they run like lawn mowers once you get them started, and really don't require much maintenance. And parts like run capacitors and start capacitors are pretty cheap on Amazon. Owner's just don't know how to service their AC so they forget about it until they have problems. And RV shops will convince you to replace your AC rather than repair it in a lot of cases, which is a shame and puts a stain on Capitalism if you ask me.

Anyway... At home just run the extension cord and you are done.

At the track, if you don't use your microwave then you can run your trailer AC by just plugging into an RV outlet, but as explained, if you check your Sub Power Panel you will see all your "Receptacles" (outlets) are on Circuit #1 (L1).

...And then you have to fish an extension cord thru a window, which will let your cold AC out!

MY PERSONAL PREFERENCE is to kind to your generator.
And to do that you need to build your own Circuit #2 outlet by tapping into your ATS ....AND ...AND add a circuit breaker.

* Turns out, these mini 15A, 115V CBs are not common. So you will need to order them off Amazon or maybe Grainger will carry them.

I'm using the reset type because it is small and I can splice it into my hot 120V wire to protect everything that comes after it.

Note: I cut into my ATS cover, but you could just mount a metal box on top and let it protrude. That's up to you. But if you have never worked with electricity before, please as someone to supervise your work.

Good luck.

[bjboles]

Thank you. Do you have a pic how you wired your ATS outlet?

[bjboles]

So I'm going to install a outlet like you did. I will put a 20amp push button circuit breaker and use a 12g 25' extension cord.

Does this setup allow me to run the RV basement AC at the same time if I switch hot water heater and fridge to propane and dont use the microwave?

[imnprsd]

Sounds like a plan.

However, I don't think 25" are going to be enough by the time you lay it all out. And 50' of 12A is manageable, but you rely only need it if you have 12A-16A loads (continuous).

The reason I like the way I did it is because I can unplug my portable AC at the ATS and add a short extension cord to shore power.


Note: If you are runing 50' to your trailer AC and another 50' to your house, then yes, I would use a 12 gauge extension cord for 100' total...

...And you house breaker should probably be 20A or you will only be able to run your trailer AC for (who knows) 1hr, 2hrs, maybe more.

Your goal, and my goal, WHEN ON GENERATOR POWER, is to run more amps on Circuit #2.

In the pictures below you can see how my Main Power Panel alternates L1 and L2 every other CB.

I don't know why they call it Circuit 1 and Circuit 2 when referring to loads, but someone out there probably knows? I think it's a good idea so you know your are talking about load current when referring to Circuit 1 and Circuit 2 vs. power supplied from a transformer with a center-tap on a telephone pole some where.

Anyway, you will learn a lot by turning off your 50A-L2 (black wire) breaker in your coach and then taking voltage readings off the bus bar inside your Main Power Box.

And remember, your Intelletec EMS 620 board can only monitor and shed loads in your Main Power Panel. It has no control over Circuit #1 loads in your Inverter Power Panel (aka Sub-Main Panel).

Look at your circuit panel and then you will know what you can run and what your can't run. The RV manufactures try to make this stuff both bullet proof and idiot proof. Meaning, when people do dumb things you still can't hurt yourself. (Ha Ha!)

What you want to do, and what I just did, makes sense. Why? RVs are set up to operate most of your creature conveniences (AC-loads) on the inverter. Things like your washer dryer and vacuum are not necessities and also take a lot of amps to run. So you are not going to run these on battery-to-inverter-to-120V. That is why these are on Circuit #2.

Your microwave is an creature comfort people want to use when boondocking and or just pulling over at a rest stop. So that is why you will find your microwave CB in the Inverter Power Panel (aka Sub Main Panel).

IMO, and I don't care what other people think when they say your can run up to 50A, because they don't know what they are talking about; and they have never tried it.

As I explained in a previous thread, you have to consider the type of loads you are running (inductive type loads or resistive type loads) and then you can count the total amps on the circuit.

Note: You have a series of protection built in to your power grid. First there is 50A total on any one circuit, but running continuously at 60% of that is 30A; and 50% of that is 25A. So in reality, a 50A service ATS is supposed to run safely, in the 25-30A space. And your ATS-5070 will, but only for 2 hours or so at 28A-29A.

I know, because 3 weeks ago I was camping on the beaches of Port Aransas and I was running my generator with my basement AC on and my portable AC and my residential refrigerator, pulling 28A-29A.

Then 2 hours later I caught my amp meter heading north of 36A and I quickly shut off the portable AC and then my basement AC.

So I know from experience you can't run 28A for more than 2-hours and then I found some information in my Onan Generator Manual that explained you are supposed to de-rate your amp-loads by 80% after 2 hours of use. That's a fancy way of saying the Onan inverter board is getting hot and you better cut back hour amp draw or else.

SO WHAT MAKES IT POSSIBLE FOR US TO ADD AN AC?

Answer: Circuit #2 is terribly underutilized.

Just look at those creature comfort CBs in your main power panel and you will see you don't use many of the C2 appliances at once. However, I still recommend you do the math.

So then... it's when you are an 30A-Service or 20A-Service that your EMS kicks and sheds loads.

REMEMBER: When you plug into your house wall socket you have to manually switch to 20A-Service on your EMS Panel.

Last but not least. You don't have to put the wall socket inside the box. I.e., you could mound another metal box to the cover of the ATS and you will have more room.

If you do what I did, make sure your lay it out so your circuit breaker fits inside. I might even suggest you add a piece of cutting board plastic (Mylar) inside too. This will add some additional protection.

Notice in the picture below I turned off the Basement AC #2 Compressor CB. This is because I don't need it in 85F or less DRY heat. However, in humid areas I expect to run both compressor on my basement AC and my portable AC.

I really like this portable AC. And with a straight-8" exhaust it does not put any heat into the room, which is normally a problem with a portable AC. Maybe this is why I seem to be fine with an 8,000 BTU portable AC and do not need a 10,000 BTU model.

Note: I choose not to get a heat pump, but maybe for those of you who would benefit from another room heater, you guy should spend $550-$650 for this option. Just make sure it is no taller than 27-3/4" high and 14-1/2" wide or it may not fit inside your cabinet.

[bjboles]

OK. So what wires behind the ATS do I need to wire the circuit breaker and outlet to. Do you have any pictures behind your showing how you connected the outlet?

[imnprsd]

Here's the $7 push-to-reset circuit breaker on Amazon. I'm posting it so you can see it does not look like your home CB, but it does the same thing.

https://www.amazon.com/gp/product/B0...UGKI63QO&psc=1

If you get a bigger AC than 8,000 BTU (8A) and run a 14 gauge, 50' extension cord inside your RV, then I would use a 12 gauge extension cord and a 20A push-to-reset CB.

Remember, the CB is there to protect the wire from burning up and starting a fire. It is not designed to keep you from getting shocked or electrocuted.

WIRE DIAGRAM

To wire to the breaker you just put it in series with the black wire out of the ATS to the outlet.

These pictures show my 15A wiring diagram (modification). Your 20A will use 12 gauge wire and a 20A outlet.

Note: If you buy the square outlet it will be easier to cut the hole. And then I used some water proof tape that has butyl on one side to cover the 2 self tapping screws on the inside of the ATS cover, because I did not want anything rattling lose over time.

BASEMENT AC TIP

You can buy this water proofing tape at Walmart (not HD or Lowes) or on Amazon. I use it all the time is I highly recommend you buy a roll for all types of applications. It's made by "Duck" and it's a Walmart exclusive item located with the gorilla tape. ...And you will use this stuff to seal the basement vent seems that open over time and let your cold air out of the vents, which is why people complain about their basement AC not doing a good job cooling the coach.

NEWS FLASH: It is not the basement AC that is the problem. The problem is the Winnebago do NOT put much tape at the vent joints nor did they insulated the vents the run up the rear cap and into your roof. (Cheap SOB's!)

So what I did is tape and then Flex Seal around the bottom of the AC, where the cold air comes out.

[bjboles]

Thanks. This will help tremendously! The green ground wire will just go to a chassis ground correct? I added arrows to ensure I have the connections right. Is this correct?

[imnprsd]

Yes. Like a house the green, ground wire is never in use until you need it to be.

However, it is not as good as a "fail safe" as GFI (Ground Fault Interrupter) switch.

Current will take any path... but seeks out the least path of resistance. This hopefully the ground wire.

So in the diagram above... notice there are no ground connections in that ATS terminal block. Ground it so the metal box.