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lachrimae's avatar
lachrimae
Explorer
Jan 17, 2014

Breaker for enclosed trailer?

Hi,

I think I've reached the end of my Googling skills and would really appreciate your guidance.

I am wiring my 6x12 enclosed trailer for a rooftop (13.5k) AC & four duplex outlets that will be used for basic purposes such as charging phones & computers and running some LED puck lights. Currently I don't have any plans for a DC environment.

I have a 30 Amp inlet that will be connected mostly to a pair of EU2000i generators and sometimes to a 50 or 30 Amp RV park outlet.

My issue relates to finding the best (safest) option for a breaker panel.
I am planning to use a 20A breaker for the AC and a single 15A breaker for the outlets.
If I use a main lug panel (no main breaker) those two breakers could total 35A and I am concerned that there would be a potential hazard since I'll be using a 30A extension cord as well as 10/2 wire from the inlet to the trailer's breaker.
I can't seem to find a 30A main breaker panel and most seem to be 100A or higher... So if I was to install a 100A main breaker I would still have the same issue of potentially sending 35A across my 30A extension cord.
Another alternative I've considered is using a 30A breaker on a main lug panel and then back-feeding it in order to create a quasi-main breaker, though this seems to be a controversial method on the internet, and if it's dangerous in any way I'm not interested.

Do you know if there is a 30A main breaker available on the market? Is it possibly ok to forgo a main breaker and just use the 20A & 15A breakers? Am I over-thinking this?

Thanks in advance,
Mark
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Jan 17, 2014
    You should be using a "Main" panel, one 30 amp breaker (The black wire on the shore cord goes to this) and the 20 and 15 go beside it.. Most RV dealers have boxes for you.. progressive Dynamics makes a real nice one that is designed to mount flush in a wall.. I would want at least one spare slot in case you ever decide to put in a 12 volt system.

    NOTE: for simplicity,, You might want to consider a 12 volt lighting system.. The difference is instead of a converter and battery, you use a un-regulated power supply (Cheaper than a regulated one) you need about 2 amp per 1141 lamp.

    I design and build my own power supplies.. Some of 'em are quite heavy, I do not do converters however (Have a design I can use if I wished to build one).
  • tvman44's avatar
    tvman44
    Explorer
    Jan 17, 2014
    The connector where you plug in will be protected so you could get by without a main breaker. But I would get a small 4 or 6 pole panel with out a main breaker and put a 30 amp single pole breaker wired backwards as a main, that is how the RV manufacturers do it most of the time.:)
  • Dusty_R's avatar
    Dusty_R
    Explorer
    Jan 17, 2014
    You don't need a Main Breaker in this case. The breaker, should be 30 amp, that feeds the receiptical that the #10 cord is pluged into, will protect the cord.

    Dusty
  • time2roll's avatar
    time2roll
    Nomad
    Jan 17, 2014
    Just get a single pole 30a breaker and feed the panel through this breaker. You connect the cord to the breaker and it will limit you to 30 amps. This is how a standard RV panel is wired. NEC allows up to 5 branch circuits.

    I do believe NEC allows 2x 20a breakers on a 30a supply without a main breaker.

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