How to run both AC's on a 30 amp site with a 50amp RV

[Lantley]

The below is a slightly edited repost that I made in July on the Open Range Forum.
This post was made after I had tested the RVsafepower transfer switch during a trip to Myrtle Beach.

I installed the RV safepower Transfer switch of few months ago. This switch was designed and created by a Open Range forum member.
When the inventor first posted of his contraption I initially dismissed the entire idea.
I eventually followed his post and realized if his device worked it would be a real game changer.
I am to report from MB state park where it is 95º hot and humid that the device works as designed. I was able to fire up both A/C's and run them continuously without issue.
One of the unexpected outcomes I experienced after buying my 50 amp 399 BHS in 2012 was that I found myself chasing 50 amp sites.
I did not like using the energy management techniques required to stay on 30 amp sites. Furthermore I could not run both A/C's on a 30 amp site which is a total deal breaker in the summer months in the mid Atlantic.
By chasing 50 amp sites I had really changed my destinations.
Seldom did I book state parks. I was forced to always go private over public due to the need for 50 amps. Lots of familiar regular places were eliminated from my itinerary.
Several great state parks were replaced by places with 50 amp sites.
Well that has officially changed. The RV safe power transfer switch allows me to plug into the 30 amp outlet as normal and then plug in a 2nd dedicated auxiliary cord into the 20 amp outlet to power my 2nd A/C. The system was flawless in the intense Myrtle Beach heat.
For anyone interested in running both A/C's on a 30 amp site or desiring to stay in older parks with only 30 amp sites the RV safepower switch is a game changer.
The switch is specifically designed to work on GFI outlets without tripping the reset. It is a transfer switch not an adapter.
It is wired into your breaker box and allows you to feed the AC or selected appliance from the traditional panel or from the CG pedestal.
Once installed it is a true game changer.


For the most part I am booked at 50 amp sites the remainder of this season.
However next year 30 and 50 amp sites will be on the schedule.

For the record I have no affiliation. I am just trying to spread the word on a fantastic product/idea. This transfer switch is a real game changer

Link to product

[pianotuna]

Hi Lantley,

Yes, I have protection on my auxiliary shore power cords.

[Lantley]

pianotuna wrote:
Hi,

If it is a modern pedestal there will be a breaker. If it is not then there will still be a breaker at the shore power panel.

Honestly I don't want to rely solely on the pedestal breaker. This is why my RV has its own panel and protection.
The aux. circuit could be wired with protection or it could be just a direct wire plug in.

For those that state they have done this manually for a whole lot cheaper my question is do you have any form of overload protection or did you just wire a cord to the appliance and plug it in?
The RV safepower has circuit breaker protection and meets UL standards.
Are the cheaper methods really and apple to apple comparison?

[pianotuna]

Hi,

If it is a modern pedestal there will be a breaker. If it is not then there will still be a breaker at the shore power panel.

[Lantley]

pianotuna wrote:
No. But you do have breakers in the RV.

Voltage drop is far more of a concern than overload.

Lantley wrote:
For you plug and play or manual switch guys are you relying solely on the pedestal for overload protection?

Yes I have breakers in the RV. Hopefully we all do. However some of those replying are manually creating a circuit by plugging a cord into the 20 amp circuit on the pedestal. Is that manually created circuit protected? Or are they relying on the pedestal?
Essentially my transfer switch does this but it is circuit breaker protected so my question remains are the manual guys added circuits protected?

[pianotuna]

No. But you do have breakers in the RV.

Voltage drop is far more of a concern than overload.

Lantley wrote:
For you plug and play or manual switch guys are you relying solely on the pedestal for overload protection?

[Pirate1]

Some guy used to sell these called dual power adapter. I have one installed and it comes in handy to just power that rear ac with it's own cord. The gizmo has it's own small breaker too. I still have all the wiring instructions in case someone needs them. PSRV is out of business.

[myredracer]

My take on this device is that you *could* be increasing voltage drop using it leading to AC damage. NEC requires a demand load of 3600 watts for a 30 amp pedestal and does not take into account a 30 and 20 amp recept. running simultaneously (a 30 amp pedestal has one hot and one neutral, unlike 50 amp ones). A 13.5/15.0 BTU AC draws around 15-16 full load amps at 120 volts (for ex., Dometic info.). By running 2 AC units off a 30 amp pedestal you will be drawing 30+ amps plus any other loads running inside. A run of 30 amp pedestals gets derated to 55 percent for 7-9 pedestals. Depending on how old the CG is and how it is wired and/or where you are on a run of pedestals, you could be seeing low voltage that can damage an AC unit. If the voltage goes down, AC units will draw more current and exacerbate the voltage problem. AC units draw around 5-6 times their full load current during startup and can cause an AC unit to struggle to start or trip a breaker. Sometimes the voltage may look okay before you turn on an AC unit but can take a big dive when started/running.

If you're going to use the transfer switch, I'd at the least use a permanently mounted voltmeter inside and keep an eye on the voltage. Better still, use an EMS so you are automatically protected. But then you've got two hot circuits coming into your RV...

If you consider the NEC and AC unit manufacturer's specs, running two AC units is over the min. requirements for a 30 amp RV and that's *if* you have a full 120 volts and aren't running any other loads. It may seem like it's all okay but damage is cumulative over time and an AC can fail for no apparent reason, akin to heat damage in ST tires. Are the AC manufacturers okay with using a 20 amp recept. for running a 2nd AC?

FWIW, all 30 and 50 amp pedestals are required by code to have a 20 amp GFCI receptacle. Old CGs may have no 20 amp recepts. (or 50 amp) because they could have pre-dated code requirements. It wasn't until the 2005 NEC edition that they increased the no. of req'd 50 amp pedestals from 5 to 20 percent. Unless you stay in higher end RV parks or an owner has intentionally built above. min. code, finding a 50 amp pedestal can be next to impossible in the high season. So much for all the 50 amp RVs manufacturers are selling.

[greenrvgreen]

I have a 2-slot small plastic "spa" breaker box, that I populated with a single twenty and a tandem 20.

[Lantley]

For you plug and play or manual switch guys are you relying solely on the pedestal for overload protection?

[greenrvgreen]

I wonder if there's a rotary switch that could switch between three (3) sources (make-break-make-break-make)? Could one of the Blue Sea switches do that?

[time2roll]

Manual switch is fine.

Search Amazon for Leviton 1286-w $50

[greenrvgreen]

The cost of parts for this looks to be about $50, and you're posting to a group of tinkerers (and skeptics). Those that think it's a good idea (like I do) will go out and do it themselves--or have already done it, like I have. I use manual switches and/or simple plugs and receptacles for switching sources.

I'm a big fan of 30A+20A aux input, which I have now on my current TT. However, I now suspect that the ideal setup is a true 50A that runs off only one leg, while the other leg is used as a switchable source for powering aux items--electric heaters, additional AC's, etc. To be clear, when true 50A is available, the aux items run off the 50A leg. But when using 30A or gennies, the aux source can be switches to 30+20 or a second gennie.

[Lantley]

smkettner wrote:
$350? And you have to fiddle with it?

Same thing $60 20 amp transfer switch (automatic)

Add a 5-15 or 5-20 inlet from Amazon if desired and you are good to go.

Actually it not fiddling it's insurance.
You really don't want the switch to be automatic. The manual operation ensures 2nd AC will only run on pedestal circuit.
If switch would automatically switch back to main internal 30 amp circuit you would run the risk of tripping the 30 amp pedestal circuit leaving the rig with zero electric.
Let's say 2nd AC causes a trip circuit main AC will continue to run however with auto switching. Suddenly both AC's are running on 30 amps
If your around no big deal but if you're away from the rig the breaker will trip leaving you with zero electric.
The switch is also designed to run on GFCI circuits.
Often motors and AC units will not work on GFI circuits. Just manually plugging your 2nd AC circuit into GFI device often will not work, the GFI will trip.
I agree $350.00 is pricey but if the unit delivers foolproof operation with UL listed circuit breaker protection, I'm OK with it.

[Lantley]

MrWizard wrote:
no offense to the OP
but you ARE using 50amps of 120vac not just 30amps

you are able to use a 30amp SITE, because you also use the 20amp outlet

if there was NO duplex outlet, you would be limited to 30amp only , and only (1) a/c

I agree that the device uses 30+20=50 amp total not just 30
I did say 30 amp site however. Most (not all) 30 amp sites will have a 20 amp outlet available.