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Bob_Landry's avatar
Bob_Landry
Explorer
Mar 25, 2014

2nd 30A Service

Here's the latest project, an upgrade to a second 30A service. I didn't go to 50A because of cost. Replacing the EMS, the 50A inlet, converter, and shore power cord would have been cost prohibitive and I'm able to use some of the items I had left over from a Class B that I built several years ago.
The electrical panel is a Blue Sea marine panel that was in the van. it came with a dual 30A breaker because in marine applications, you are required to break both hot and neutral legs, not so for RVs. So, I modified this panel to accept 2 separate 30A breakers with a sliding lockout to allow only one source at a time to feed the panel. There will be two 30A inlets, one going through an EMS to the existing converter, and the second which will go directly to this panel. Since I'm getting the two 30A feeds using a breakout box(shown below) plugged into the 50A outlet, both legs can share the same neutral and ground and those will be tied to their respective buss bars. This allows me to have 60A of usable service running off the CG 50A service. One of the 30A breakers is fed directly from the second power cord and the other is fed from the primary power cord. The sliding lockout allows me to use either the second power cord input to the second panel or the primary and this lets me combine both panels in the event I go where there is only 30A service. By combining both panels, I'm back to the original configuration of running everything off the CG 30 outlet if necessary.
The panel has green LEDs to indicate when something is hot, a nice touch, and a red LED that originally was a reverse polarity indicator but can be rewired to show when both panels are in parallel. When I split up and separate the loads, I'll leave the inductive loads on the leg that is EMS protected.

I also have an additional 20A service that I use to run fans or space heaters when necessary so that I don't have to shut off appliances when I run them, thus, no tripped breaker. This is a total of 80A of available power, not as good as 50A, but with one AC it will work fine and I won't have the AC tripping off when DW uses hr hair dryer or runs the microwave.



  • Hi,

    My "break out box" is a bit different. I have a 30 on one leg and two 20ties on the other leg. They each have their own breaker.

    My wiring changes inside the rv are plug and play as well. I used male plugs for the converter and water heater. I used female plugs for the auxiliary shore power cords. This gives me a maximum of 30 plus 20 plus 15. I added additional outlets to each auxiliary shore power cord so in winter time I can run a lot of extra electric heat.

    The nicest part is that when there are multiple 15 amp circuits available (Church parking lot), I can have 45 amps to use.

    It takes me 20 seconds to move from modified to OEM for the wiring.
  • Hi,

    You probably could have upgraded to 50 amps in a few minutes more time than you have into this project.

    One way that Weekend Warrior used to upgrade the trailers to 50 amps was a field installed 50 amp panel mounted in the garage area or a storage compartment. It would have one 30 amp breaker to feed the existing 30 amp main panel built into the RV, and more breakers for things like the A/C units and dedicated new 120 volt receptacles in the garage area for customer loads such as a air compressor or other things they desired.

    It would be quick and easy to install a 50 amp power panel into a basement storage compartment, then run a new 50 amp cord from there to the park receptacle. Run a 30 amp line to the factory installed panel, and then transfer any loads that you desired to the new panel.

    Anyway what you have done will work. But it might not comply with NEC regulations of only one power supply per vehicle.

    Fred.
  • Yes, functionally, my breakout is the same as the adapter you showed above. Mine is home made and I built it before I saw that Marinco made one.. It's 100% safe and it works. The purpose of the slide lockout it to be able to only have one 30A breaker on at any given time. It's impossible to turn both on at the same time. When the panels are combined, the outside plug for the second power cord is isolated because it's associated breaker is turned off. This is a standard practice and configuration in the marine industry and the panels are made to specifically do this. The only difference is that we are required to break both the hot and neutral leg where as NEC does't require it on a trailer. I changed this panel around so that only the hot on both legs are switched. That's the only difference. Everything is well protected, the 50A outlet is double breaker protected at the pedestal, the two 30A inputs at the panels are breaker protected, and then it goes to the standard branch circuit breakers. There's nothing "Rube Goldberg" about it.
  • RoyB's avatar
    RoyB
    Explorer II
    I guess this isn't any different from a standard RV50A MALE PLUG to two RV30A FEMALE SOCKET adapters.


    Your plan looks a little more heavy duty maybe... Hoping the combined weight of all of this will not want to pull the RV50A PLUG out of the camp ground pedestal when all is connected up. You may want to secure the two RV30A Plug ends of the two shore power cables to the camp ground pedestal using a stretch rope maybe...

    Looks like it work just fine as long as you never cross the NO-NO hookup situation of having a HOT PLUG with prongs with AC VOLTAGE on them. Your two 30A shore power cables will plug into the two available RV30A wired receptacles of your adapter.

    I didn't read close enough but I assume the two separate 30A feeds for the modified BOAT POWER PANEL inside DO NOT EVER send AC VOLTAGE out to one of the unplugged 30A Shore Power Plugs under any circumstances which would be deemed NOT SAFE. i.e. NO WAY to CHEAT the SLIDE LOCKOUT lever to create an UNSAFE condition of having HOT AC VOLTAGE on your RV30A plug end of one of the RV30A Shore Power cables when unplugged from the 50A source receptacle...

    I think you know what I am referring too...

    Roy Ken
  • Each leg fed by a 50A leg with 30A breakers at the trailer, one for each leg. You don't have to break neutral in an RV. The plug on the brake out goes to the 50A outlet, 50A on each side.
  • Old-Biscuit wrote:
    60A total on a 50A feed..........:H


    No, 30 amps on each leg. Should be fed with a 2 pole 30 amp breaker.
  • Nice idea. I may look at doing something similar. It really is very annoying when you have to turn the a/c off to run the microwave. This may also be a good way to add another a/c. I presume the yellow piece is a 50A plug?