The limiting factor in your wiring is the wiring. you can't have more than a 20 amp breaker if the wiring will only handle 20 amps. From the breaker out to the pole the wiring is rated at 30. If you put a 30 amp inside the triler, the 20 amp rated wires will melt before the breaker will trip. The 20 amp main interior breaker is only for the trailer wiring, not the air conditioner, that wiring is completely seperate.
I'm suggesting that you add a 30a main breaker, and leave the two 20a branch breakers as they are. The 30a breaker limits the energy flow into the buss bar, and the two 20a breakers limit the energy flow out to the branch circuits. None of the trailer wiring other than the main 10 ga. service cord would be exposed to 30 amps.
The 10 ga. service cord is protected by the 30a breaker, and the only wiring between the main breaker and the 20a breakers is the buss bar.
I'm suggesting that you add a 30a main breaker, and leave the two 20a branch breakers as they are. The 30a breaker limits the energy flow into the buss bar, and the two 20a breakers limit the energy flow out to the branch circuits. None of the trailer wiring other than the main 10 ga. service cord would be exposed to 30 amps.
The 10 ga. service cord is protected by the 30a breaker, and the only wiring between the main breaker and the 20a breakers is the buss bar.
That would work, but I think it might be making something unduly complicated, adding another component that would then be able to fail.
Remember, if it ain't there, it can't break.
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Terry Change is inevitable, except from a vending machine
AIR#2611
Are you really just going to install a 30 amp breaker in the service line as a "surge protector" for you breaker box? As Terry says... adding that would likely make just one more item to fail! I am confused as to what was said concerning a separate power source for the AC in your wiring. I have two 20 amp breakers in my box one for the AC and on for the 110 volt outlets. Is this what was meant by separate wiring? Also any power coming off the 20 amp breaker is on household 20 amp 12 gauge wire right? This is a standard way to wire an air conditioner (on its own circuit). If you were to run a third wiring source off a third 20 amp breaker for water heater/heater power there will have to be all new circuit wiring running to those items unless you can separate the circuit wiring at your terminal board. Is this not correct? I have an electrician who will be making all my final connections in my trailer but I would like to know ahead of time that I understand the way things should be. Someone please correct me if I'm wrong or misunderstand how the wiring is in these trailers. Happy Trails, Ed
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1967 Safari Twin "Landshark" w/International trim package
1999 GMC Sierra 1500 SLT FORUMS MEMBER SINCE 12/16/2004 AIR#7110
"My tire was thumping, I thought it was flat! When I looked at the tire... I noticed your CAT!" Burma Shave
That would work, but I think it might be making something unduly complicated, adding another component that would then be able to fail.
Remember, if it ain't there, it can't break.
It might be added complexity, but the code sometimes requires things for safety and this is one of them.
I understand that some early Airstreams may have had separate power connections for air conditioners. That was before 30a supply stands were common.
The current code (NEC 551.42 (C)) requires any unit with two to five, 15- or 20-ampere branch circuits to have a distribution panelboard rated at 120volts maximum with a 30-ampere rated main power supply assembly.
Without a thirty amp main breaker, it is possible to be pulling 40 amps (2x20amps) through the 30a rated service cord.
While most RV power stands have 30 breakers to protect the plug, they are not universal, and NEC requires only a disconnect.
If your wire into the trailer is #12 or better, it can handle a 30 amp breaker at the street. Each 20 amp breaker in your panel will take what ever it needs. The 30 amp breaker in the street will now be your "MAIN" breaker providing yoiur cord to the trailer is #12 stranded or better which it is I'm sure. I have never seen anything smaller than#10 stranded wire.
Retired electrician.
for the moderator::: how do I post my own question on this page. It has to do with removing a broken window? I know this is out of context but I am new and don't know how since there is not a means on this page to submit my own question. Thank you. Ted
Ted, click on the forums tab at the top of this page. Look down thru there and you will find a sub-forum for windows. CLick on that link. At the top of the listings there will be a "new thread" button. Click on that and you should be able to figure it out. If not, come back here and we'll help you thru it.
Jim
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Guess I'm getting old. Don't recognize any of the famous people in the "Got Milk?" ads any more.
I pretty much figured out this morning that I need to do what Markdoane is suggesting in post number 11. I don't like the idea of not being able to isolate the entire panel (without unplugging the Airstream from shore power). That will leave me with one 30 amp main, 1 20 amp for the Air Conditioner and one 20 amp for the remainder of the 110v outlets. I'm also going to add another 15 amp dedicated for just the microwave.
What got all this started is that for the past few days it's been very cold here and I've been working in the camper with a small (1000 watt) ceramic heater in there. I'm getting interior wire heating up a bit while running that heater. Warm, not hot. The 30 amp main that is plugged into the pedestal next to camper is getting a bit warm at the plug only. Just trying to look at everything and see where I can eliminate problem areas.
Thanks for the tips everybody.
Jim
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Guess I'm getting old. Don't recognize any of the famous people in the "Got Milk?" ads any more.
from what i understand you have a 4 circuit 30amp panel. it is directly wired to the bus w/ 2, 20amp brkrs and fed from the street w/ a 10ga. wire from a 30amp breaker(from house). this is fine and by code. the 30amp brkr protects the cord and the 20amp brkrs in your camper protect those devices. between the 2, 20 amp brkrs, if you draw potentially 40 amps the 30a brkr will pop protecting your camper. this is the cheesey way to do it.
you can however do what you said, add a 30 amp main, feed the panel thru the 30 amp brkr and thus the other breakers/panel. hope that helps.
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" If everything is working, something is wrong ! "
I have a '67, 22ft Safari and I noticed that the outside 110v was wired with aluminum wire--I think I've seem aluminum wire behind the control panel too.
Should I be concerned about this, the outside wiring seemed to be a bit brittle. In case I have to re-wire, what's my life looking like, how tough is it too change?
30A “main” breaker at top left wired to feed the panel.
(you can see the jumper wire connecting the main lugs looping under the breakers)
20A breaker at top right is for AC
15A breaker at bottom left handles the 12v converter & rear receps.
20A at bottom right handles the balance of receptacles including frig.
Note:
Check the tightness on all the connections (with power off). Loose lugs can cause overheating. Check the scorched jacket outside the box on the right. I think this
is from overheating on the old AC. There was a rubber strap holding the wire to the wall and at some point in it’s life the temp. was abnormal.
__________________ Travelers by aluminum roadships, loyalists to one species, masters of convenience, herdsmen steeped in maintenance and restoration.
Thanks, Martin. Is this from your Argy? That panel looks an awful lot like mine, with a couple of extra breakers, or course. As I stated somewhere above, what got all of this started was the fact that some of my wall outlets are heating up. I spent some time last night looking at the 10/3 wire inside trying to find a weak spot where things might have over heated at some point. Haven't found it yet, but I need to do a better inspection in the daytime when I have more light to work with. I think the best idea at this point is to plan on changing out all of the wall outlets with new, rearrange the breaker panel and inspect the Romex very closly.
Jim
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Guess I'm getting old. Don't recognize any of the famous people in the "Got Milk?" ads any more.
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