Add extra circuit

Hi,

Best to stock up on male and female 30 amp ends if you "push" the 30 amp right to the limit. DAMHIK

I've even had 30 amp plugs fail when carrying 15 amps, which seems a bit insane. And yes--both ends were brand new and treated with anti-corrosion spray.

myredracer wrote:
In Canada, it is acceptable by code to connect & operate fixed heating appliance loads (baseboards, eg.) at 100 percent of the heating circuit's breaker size. Basically in an RV, you can plug in as much stuff as you want until the 30 amp breaker in the pedestal or converter/panel trips, then you'll know it was too much.

OP, you in no way need a 50 amp (120/240 volt) service to be able to run a single AC unit in an RV. Before going extreme and spending a ton of $$, you should try and figure out why you are having problems.

If you are having trouble, it could be due to low voltage at the CG. When voltage goes down, an AC unit draws more current and if the voltage gets low enough can trip a 30 amp breaker. People run one AC + MW and other loads together all the time. I highly recommend getting a voltmeter that plugs into a receptacle in a visible location inside and routinely keep an eye on it. In no case should you run an AC below 105 volts because it will cause damage. If you are encountering low voltage frequently, I recommend getting an autoformer like a Hughes unit to boost the voltage to an acceptable level. We bought a good used one last year for $225. An EMS unit is also recommended and will automatically shut the power off when the voltage is low (and monitors for other conditions too).

There is a downside to having a 50 amp RV. The NEC only requires 20 percent of RV parks (CGs) to have 50 amp pedestals. Before 2005 only 5 percent was required. Finding a 50 amp pedestal can be extremely difficult in the high season, unless you go to a high-end or some gov't CGs that has exceeded min. code requirements. Look around a CG and you will see lots and lots of people running 50 amp RVs with a 30 adapter at pedestals.

One thing that might help is a "hard start" capacitor in the AC unit. These are intended when using a generator and the AC starting current is too much for the generator. Can help with CG low voltage too.

Adding a 20 amp power inlet and plugging into the 20 amp receptacle in a pedestal is an option and many have done this for a 2nd AC or general purpose use. ALL pedestals have a 20 amp GFCI by code. There is a downside to this too. CG wiring is not designed (per NEC) to have both a 20 & 30 amp running at full load simultaneously and you run the risk of increasing voltage drop.

I'd check the blades on your shore power cord. They need to be kept clean and shiny. Never plug into a pedestal without shutting the 30 amp breaker off. If you don't, you will get pitting on the plug blades which builds up dirt/carbon and causes resistance which adds to voltage drop (and can overheat and melt).

I installed a wall mounted LED voltmeter and ammeter. The current rarely goes above 15 amps and we've never had to do any kind of load management (have 1 AC).

GordonThree wrote:
Yes a 30a circuit is only good for 23-26 amps continuous duty, the microwave counts as an intermittent load.

Sorry, but that is incorrect. I saw someone post this in another thread the other day and warrants correcting.

A 30 amp breaker can run indefinitely at 30 amps, as in forever. They are designed that way in accordance with UL/CSA. RVs are not fixed, permanently wired loads like in a building which by code cannot connected to fixed loads greater than 80 percent of the breaker rating. Circuit breakers have a thermal-magnetic inverse time-current characteristic.

The graph below shows the tripping characteristic and can be applied to any standard molded case breaker. A clearer image can be found here. This graph is generic and note that at 1 times whatever breaker rating you have, it will operate indefinitely. The higher an overload is, the sooner it will trip because current through the thermal bi-metal element gets warmer sooner. When the current gets high enough as in a short circuit, the magnetic element trips instantaneously. You can draw somewhat over 30 amps for short periods while running things like say a MW, and won't trip a 30 amp breaker. If you were drawing 38 amps for example, the breaker would not trip for approx. 150 - 500 seconds

In Canada, it is acceptable by code to connect & operate fixed heating appliance loads (baseboards, eg.) at 100 percent of the heating circuit's breaker size. Basically in an RV, you can plug in as much stuff as you want until the 30 amp breaker in the pedestal or converter/panel trips, then you'll know it was too much.

tinstartrvlr wrote:
Think a new 20 amp circuit is the best way to go, based on what everyone is posting here.

Seems simple enough to just add another 20 amp circuit; but not sure I could add it to the existing panel. There would be room on the wall to add another small breaker next to the panel if necessary. It is a straight shot from the box to the outside wall, through the kitchen sink cabinet, unlike the current 30 amp inlet. (why the mfg put the inlet 20 wire feet away from the box baffles me!)

I haven't looked online yet to see if there is a 20amp connector that I can put on the outside of the TT, but thinking there must be one somewhere. Or can I just use another 30 amp connector and an adapter at the pedestal?

Thinking this is doable at not a huge cost!

Check out this album CLICKY to see the details on how I added a second 30A service to my trailer for a reasonable cost. The captions show the parts/cost and where I got the items. This now gives me 60A total service and the ability to not to have to touch the existing electrical service. I still have to be cautious since I can't run the WH, A/C and microwave all at the same time, but that is easily managed since I can shut those on/off from the same location so it's not that much of an inconvenience.

Larry

no..its illegal.. against electrical code, to add it to existing breaker panel

NO way to isolate the new circuit
the existing panel already has a HOT BUSS

you completely disconect the romex wire for the A/C circuit
pull it out of the breaker panel, hot neutral ground

stick wire in NEW box, with NEW 20 amp circuit breaker
run new 20amp power cord from new breaker box

the NEW circuit is Now completely separate from the old panel

you can place the new box, in the wall, or in a cabinet, where ever its accessible to reset breaker

Think a new 20 amp circuit is the best way to go, based on what everyone is posting here.

Seems simple enough to just add another 20 amp circuit; but not sure I could add it to the existing panel. There would be room on the wall to add another small breaker next to the panel if necessary. It is a straight shot from the box to the outside wall, through the kitchen sink cabinet, unlike the current 30 amp inlet. (why the mfg put the inlet 20 wire feet away from the box baffles me!)

I haven't looked online yet to see if there is a 20amp connector that I can put on the outside of the TT, but thinking there must be one somewhere. Or can I just use another 30 amp connector and an adapter at the pedestal?

Thinking this is doable at not a huge cost!

MrWizard wrote:
You don't need a 50 amp service, or even one leg of the 50 amp to run one a/c

Remove the a/c circuit from the breaker in the panel
Get a small double breaker box, but in a 20 amp c.f., Conner the a/c to that
Run a new cord circuit 12 gauge from box to o outside with a 15 or 20 amp duplex make plug on the end

A single 20 circuit from the power pole is all you need for the air
And this will work every where
Not all camp grounds have 50 plugs

Do that or change the th over to 50 amp service with new breaker panel and new 50 amp cord

Bingo - for the Wiz!

You could follow his advice....and/or

Often the 30amp plug at the pedestal is well worn, making for a bad connection (check it).

*If* the campground has 50amp, connect (via a 50 to 30 amp adapter)
your 30 amp service there.

That won't solve your problem - but a good connection on/for *ANY* wiring is pretty essential.

*If* the campground has 50amp....you should now have two other choices
(the 30 and 20 amp) for a secondary power supply for your A/C -or- microwave.
Convert the 30 amp to 20 - and/or (if no 50 amp), use the 20 amp and the 30 amp as posters have suggested.

You WILL be $$ ahead -vs- converting your trlr to 50 amp......and as an added bonus, you won't be 'fighting the anaconda' (50 amp cord) -
or asking the WWF (World Wrestling Federation) or RV Net for solutions to that one, LOL!

Hmmmm.....what did Travolta say in Grease......"It's electrifying?"

.

You don't need a 50 amp service, or even one leg of the 50 amp to run one a/c

Remove the a/c circuit from the breaker in the panel
Get a small double breaker box, but in a 20 amp c.f., Conner the a/c to that
Run a new cord circuit 12 gauge from box to o outside with a 15 or 20 amp duplex make plug on the end

A single 20 circuit from the power pole is all you need for the air
And this will work every where
Not all camp grounds have 50 plugs

Do that or change the th over to 50 amp service with new breaker panel and new 50 amp cord

AC breakers are designed to support continuous current at 80 percent of rating, intermittent at rating, and overload for brief periods decreasing up to it's instantaneous trip rating (usually 5-10 times rated current). This is precisely because devices such as motors have very high starting currents.

For example, the 13KBTU air conditioner in my trailer has a measured starting current of around 40amps for about 0.5 seconds and settles to a run amperage of about 9amps. If the breaker tripped instantly at 15a, it would never start the ac, or almost any other appliance with a motor. A 15amp breaker with no other loads attached will support the ac just fine.

As a side note, this is why it is so hard to start an ac with a generator. When plugged in to a mains, there is as far as a RV is concerned unlimited reserve current capacity, so that 0.5 seconds at 40amp is supported. A generator however has no reserve capacity beyond what is stated. So if a generator is rated XXamps max surge, that is it. Exceed that number and the generator trips out. This is why we play so much with our acs in order to get starting current down.

Hi,

Even better--get one of these Micro-Air Easy Start Soft Starter Kit

tinstartrvlr wrote:
Piano,

Regardless of what I do, I think I might add that capacitor anyway. Looks like it would be a good thing to have no matter what.

As long as the 20 amp circuit is enough to handle the startup, that makes the most sense. I could also use that circuit for a space heater in the winter as well.
And with 20 amp, I likely won't run into the issue of no hookup at a campground like sometimes happens when there are no 50 amp hookups.

You can make an A-Dapter that lets you plug into a 50A pedestal then provide two 30A receptacles. Say one for your present 30A shore tie, one for a second 30A cable. Or an ordinary 20A outlet and bring a heavy duty extension cord to your coach.

I've thought of doing something like this, just never have. The problem I see is twofold.

1. How to get that extra power INTO the coach. Through the Wall might not be too bad, but then, How to get it to a Load Center (Breaker Box).

2. How to distribute the new power in a useful way. 30A coach has only X-Number of circuits, so how to add some more is a real question.

We're a 30A coach, and in summer with a 15000 A/C, we can run that plus one, maybe two, "major 120 VAC appliances" like toaster, coffee maker, water heater, in addition to the converter/charger and fridge on 120VAC. 30A plugs and sockets aren't really up to continuous load at/near 30A. Campground pedestal sockets are usually about shot from people plugging/unplugging, a lot of time under load. So, even though I might be able to microwave with the A/C running, I usually don't. Our micro is a full-power one, needs its own 15A circuit. When we had a 13500 A/C and a smaller microwave, we could run "all electric" on 30A. Fridge, A/C, Micro, Water Heater all on shore tie. NOT with the bigger A/C and Micro.