Please confirm what I think I already know

Gdetrailer wrote:

DFord wrote:
As I said in my previous post which you must have missed:

You cannot use more than 24 amps on a 30 amp feed for any length of time. You simply can't get away with it. The 30 amp breaker in the pedestal or your main feed should trip if they're doing their jobs.

Beyond them tripping, your cord connectors will have heated up at that point and sooner or later, you'll blacken the blades and melt the cord caps and ruin the socket on the pedestal.

YOU CANNOT USE 3 HIGH AMP APPLIANCES AT ONE TIME ON 30 AMPS WITHOUT BREAKERS TRIPPING OR YOUR CORD CONNECTERS HEATING UP AND MELTING THE CORD CAPS.

The more boost your autoformer provides, the more amps that will be drawn. You can't get more than 24 amps for any length of time! Bypassing the 30 amp RV breaker by adding a 20 amp breaker is only going to ensure the pedestal breaker trips.

Wrong on many levels.

First of all, you CAN "use" ALL 30A of a 30A circuit breaker, the trick is it is for a SHORT TIME. You conveniently omitted the TIME FACTOR.

Circuit breakers are rated at 80% on a "continuous" basis and continuous in the electrical world is a circuit loaded to capacity for 3 hrs or more.

In reality, a 30A breaker must be able to sustain a 100% RATING INDEFINITELY, HOWEVER, NEC dictates 80% FOR APPLICATION!

Why the difference?

HEAT, yep, heating of the circuit (wires, switches, breakers) comes into play.

Heating takes TIME, so in reality, it IS possible to run a 30A load for a SHORT TIME on a 30A circuit without tripping the breaker.

OP must have a single pole "combo" breaker with 30A AND 20A breakers, combo breakers tend to false trip if both circuits on the SAME breaker are heavily loaded for LONG periods of time.

The fix for that is to use full size SINGLE CIRCUIT breakers or if box accepts two SEPARATE 1/2 size breakers or if that is not possible MOVE a lesser amperage circuit to the combo breaker (IE, change 30A/20A single to a 30A/15A single then move a 15A circuit to that breaker).

I am not a fan of those combo breakers but sometimes you do not have a choice and I have used them in those cases.

HERE is a good "primer" on CB sizing..

You do make a good point, the OP DOES need to learn to "manage" HEAVY loads. OP must learn to manually shed loads when a lot of heavy loads are needing to be used at one time.

As far as those "autoformers" goes, yes, you could use one, however due to power loses you basically are trading off one issue for another.

A 30A 120V RV gets you a max of 3600W to work with, using an autoformer to BOOST low INPUT voltage from the campground will result in a slight loss of available USABLE wattage so in reality you might only get say maybe 3400W (28A) in your RV and start tripping the campgrounds 30A breaker depending on how much the autoformer has to boost the voltage.

Power management will be critical, sometimes difficult to get used to if you are coming from a 100A or higher 240/120 service entrance life of a real home.

Personally, before dumping tons of money down the drain for an autoformer, perhaps take a hard look at what you feel are fragile..

Most electrical devices ARE designed to operate as low as 108V and not sustain damage.. If you are in a campground that is continually having brownouts of 107V or lower then it is time to MOVE ON..

Campgrounds I have been in the lowest voltage I have seen on my monitor has been 111V with an average of 119V in the summer in a park with 1800 campsites.. Heck I have seen worse voltages at a cousins home we visit in the summer time..

Gdetrailer,

How does "FOR ANY LENGTH OF TIME" as I put it differ from the way you worded it - "SHORT TIME"? It makes me wonder how much of what I wrote you actually read. I said you can't use anymore than 24 amps for any length of time. You said breakers are rated at 80% for continuous use. (30 x 0.8 = 24) We're saying the same thing using different words. There's no reason to begin your comments with "WRONG ON MANY LEVELS" unless you're trying to be disingenuous. You just reiterated almost everything I said - perhaps in words more to your liking but still your attack on what I said was unnecessary.

I'd be willing to bet any campground that found someone plugged into both the 30 amp and 20 amp receptacles on their pedestals will be asked to pay 50 amp rate or leave the park.