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falconbrother
Explorer II
Jul 01, 2015

Split 30amp into two 15amp circuits

I'm looking into converting a van we own into a camper van. I converted it into a grooming van a few years years ago and since we used a generator I just used two 15amp circuits to power the van. One circuit was AC or Heat. The other 15amp circuit did everything else. That system worked really well. However, now I'd like to pull a 30amp cord with the three prong connector so, we can use shore power at campgrounds. How is this done for the three prong plug? Does it run into a bus/circuit breaker and then become 15amps based on the specific circuit breakers, sort of like in a house? We will never get by on one 15amp circuit..
  • LittleBill wrote:
    there is literally no need for a main breaker, don't even know why people are suggesting it.

    wherever he plugs in will protect the wire from the rv to the receptacle, the smaller breaker will protect the wire inside the rv.


    The NEC requires a main disconnect (i.e. a main breaker, or a switch and fuses) when more than two branch circuits are used. If only two branch circuits are used, it's apparently not actually required, but still IMHO a very good idea for a couple of reasons:

    1. It gives a good way to shut off the 120V power to the RV for performing maintenance or in the case of an emergency. This is likely the main reason the NEC requires it.

    2. If you plug into e.g. a 50A RV receptacle and have no main breaker, a short in the electric panel or excess current use by the combined branch circuits could overload the shore power cord.

    I'd rather be safe than sorry, particularly since a 30A breaker is not all that expensive.
  • there is literally no need for a main breaker, don't even know why people are suggesting it.

    wherever he plugs in will protect the wire from the rv to the receptacle, the smaller breaker will protect the wire inside the rv.
  • Just get a small panel from Home Depot etc.

    30 amp cord to two 15 amp breakers is easy.
    I believe NEC allows two 20 amp breakers max with 30 amp supply.

    http://www.homedepot.com/p/GE-PowerMark-Gold-40-AMP-2-Space-4-Circuit-Indoor-Single-Phase

    Although a small RV panel might be a bit cleaner with room for expansion + built in 12v distribution and charging.

    http://www.bestconverter.com/PD4045-45-Amp-Inteli-Power-Mighty-Mini-Power-Center

    This will need a 30 amp main breaker and up to five 15 or 20 amp branch circuits. The '45 amp' rating is the 12 volt supply.
  • Just remember the current handling ability of the breaker is based on the current carrying ability of the wire size being used. Nomatter what size breaker, do NOT try to setup a 30 amp circuit on wiring that was only designed to handle 15 amps!!!
  • You can have more than two branch circuits, three or four, but 30 amps is the max you can draw for total use
  • You can buy the smallest circuit breaker panel at Home Depot, probably 4 circuit 120/240 breaker box. You can feed it with 4 breakers. One should be a 30 amp main, another 20 amps for the heater-A/C unit. You can pick 20 or 15 amp breakers to feed everything else, depending on the wire size. . .

    Then buy a 30 amp rated power cord. If you get a 30 amp RV extension cord, and remove the receptacle end, you can wire that to the 30 amp breaker, and wire it up just like a home. Just separated the ground and white bussbars. In your home, the main breaker box with a meter shall have the white and grounds on the same bussbar. However all other breaker panels need to have the white wire and ground bussbar separate!

    Good luck!

    Fred.
  • KD4UPL wrote:
    Yes, just like in a house. Your 30A cord will feed a little breaker panel with 2 15A breakers. Each of these breakers will feed your existing circuits. You can use a breaker panel specifically designed for RVs or you can use a "house" one form Lowes or Home Depot or where ever.


    This is correct.

    You should have a 30A main breaker on the panel, and then whatever branch circuits you need. The panel should be wired like a house subpanel, with neutral and ground separated, not bonded together. A 30A RV supply is a 120V supply—there's only one hot leg to worry about. Most residential load centers are 240V, so you'd only be able to use half the spaces in one (without resorting to some sort of a kludge).
  • Yes, just like in a house. Your 30A cord will feed a little breaker panel with 2 15A breakers. Each of these breakers will feed your existing circuits. You can use a breaker panel specifically designed for RVs or you can use a "house" one form Lowes or Home Depot or where ever.
  • The 30A cord supplies a small breaker panel. Then separate 15A (or what ever) protect the branch circuits.

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