Thor Forums

[TurnerFam]

I'll add my two cents : ) from a lot of experience:

no, the surge does not - as you are assuming by your 'calculations' that BOTH are coming on at the exact same time, which never happens. Many of us, again, as said many, many times, run BOTH roof a/c units quite nicely on 30amps quite often.... it's not the 'naysay' that many have continued to spread across these forums....it's just not true.

I certainly understand that folks 'hear' things said from others whom they assume 'know' what they're talking about, but even those who continue to spread this 'rumor' are not as knowledgeable about electricity as they should be... even campground owners sometimes fall into this same lot, even though we RVrs, ourselves, know what we can really do, even if the campground owner tells us we 'can't'...


30amps is 30amps, plain and simple. It, in itself, does not preclude anyone from using and running multiple appliances and devices all at the same time. It is simply 120v power, with a limit of 30amps of constant 'usage'. The breaker 'amp' size in the equation is simply a protection against overheating wires that were not designed for more that amount of power, or 'heat', at least not on a constant basis.

You can even have a total of 100amps of appliances and devices on your coach, like some of us do, with 50amp service, and yet successfully plug into and use a simple 30amp RV service outlet.
You are not going to run everything at the same time. You are going to use what you 'need', and everything that the breaker 'allows', all at once, until it trips.
The trip simply says: "I'm overheating, you are using too many things right now, please turn something off, then reset me and I'll be happy to continue providing you 120v power"...
You could be running BOTH air conditioners for 12 hours straight, then suddenly the breaker trips. Is it the breaker's fault? The campground's fault? Your RV's fault? The air conditioner's fault? NO.

It is YOUR fault. (I'm saying that nicely, though) : )

The RV owner is the only one in control of how 'much' is to be powered, all at the same time. Likely, in this case, while both air conditioners were running successfully for hours, both at the same time, someone decided to ALSO make POPCORN in the microwave!
The breaker tripping is just a reminder that you may not have that much 'power' to use.

The exact same thing can happen to even the largest 50amp RV service coaches... just because you have 100amps of 120v power available, you can STILL trip the breaker by trying to do 'too much' all at the same time, especially during the heat of the summer. You can run BOTH roof airs, make some microwave popcorn, watch satellite tv, charge your Devices, and have the Battery Charger doing it's job, but alas, the moment the Electric Water Heater element suddenly kicks on, everything goes DARK!
It happens even for those of us with much more amperage demands - so it's not 'amps' that's any issue, it's how 'much' you want to do at the same time, no matter what 'size' outlet breaker you are plugged into.
It's about managing your power usage, not about whether a 30amp outlet 'can't' power both of your roof a/c units.... it can.


Specifically, for two roof air conditioners to run, you must turn both of them on, by their thermostats - of course. When you turn the first one on, it will already be in momentum to start the fan, and eventually the compressor, when you then reach to start the second a/c unit. Neither will be 'starting' at the same time.

Someone may use the argument, though, that if your a/c units were both on, when the shore power or generator power is lost, both would still be in the 'ready' mode on their thermostats, which is true.
IF you then have shore or generator power restored, both would seem to want then to come on at the same time, right?
That could happen, though I believe that neither would actually have their compressor come on at exactly the same time as the other, but let's assume they did - the 'worse' thing that would happen is either the shore power breaker could trip, or the generator breaker could trip. That's exactly the breaker's job, and it would be a one-time occurrence, not a regular issue.

There are certainly different scenarios for so many of the different camping situations that all of us are in, at any given moment, and yes, breakers can trip, but we should not jump to conclusions as to why this would necessarily effect EVERY rv...

for instance, several times when we pulled into a park and hooked up, wanting to run both roof airs, the breaker would eventually trip, within 5 or 10 minutes, or even sooner, with nothing else much in play. Knowing that 30amps can easily handle both a/c units running at the same time, and since my own Main Panel's breaker did not trip first, my quick assumption was that the park's SHORE POWER BREAKER was weak. Meaning that it was not handling the 30amps as it should, as was tripping prematurely.
At one park, the owner easily replaced the 30amp breaker with a new one, and was amazed that we 'somehow' were able to run both a/c units at the same time. He had also bought into the 'rumors'.
At another park, the manager thought that I was a little 'off', as he'd heard that NO ONE could run two roof airs off his 30amp shore power, but eventually gave in to my explanation, if nothing more than to appease me, and maybe prove his own theory out, and replaced the breaker with a new one. Voila, back in business! both a/c units ran the rest of the stay, and with adding other items, fans, and a little battery charging along the way. He was confused. I still don't think he, himself, believed it.

[some may also confuse this 'amps' topic with one of 'low voltage', but the two are not the same - that's a different story for another time] : )

Have fun, travel, plug in, enjoy! : )

(don't listen to those who say you 'can't', but those who say you CAN!)