Expanding AC distribution panel

There are tiny sub panels that have as few as three breakers.

couple of things regarding NEC requirements.

dedicated appliances, fridge, microwave, AC HWH etc. are required to have their own seperate breaker.

A 30A panel is limited to 5 breakers. Ever notice that virtually all 30A trailers have no more than 5 breakers and often share outlets with the converter?


Now given all that, when I updated my panel with a transfer switch, I added a subpanel from another 30A breaker in the box that supplied the outlets & microwave, when the transfer switch transfers from shore power to inverter, ONLY these circuits are powered. No need to worry about turning on AC, fridge, HWH with the inverter on. The subpanel I added had room for 2 regular or 4 narrow breakers, probably didn't cost more than $30. very small.

Ok I found some smaller breaker panels with two to four breakers.

I'm uncertain of NEC codes for an RV which are probably required for RV manufacturing similar to automobile manufacturing requires to pass certain DOT regulations. Where the auto manufacture is required to send e.g. headlights and their design schematics to the DOT to be certified. Once a vehicle is certified by the DOT production can begin.

NEC codes may differ depending on electrical grounding requirements of a structure.

I once upgraded an old bull-dog 50 amp service panel to a 200 service panel on a 44 foot RV that was permanently mounted on cement blocks.

however I also upgrade the properties PUD 100 amp service to 200 amps .

I obtain electrical permits from the county and state (labor and industries) however I'm uncertain the relationship between those permits and the electrical re-wiring of the 44 foot RV and installation of a new RV 200 service panel that's connected to another 200 service panel installed on a pole for the PUD.

I was told if a RV is not installed on a permanent foundation then it NEC codes differ from a RV installed on a permanent foundation, same or similar to a house or mobile home. I use to have NEC schematics and tech. documents that showed me the differences and requirment. However NEC has since changed it's electrical ground codes.

In out state certain projects do not require an electrical permit.

They include:

Travel trailers.
Plug-in household appliances.
The like-in-kind replacement of lamps; a single set of fuses; a single battery smaller than 150 amp hour; contactors, relays, timers, starters, circuit boards, or similar control components; one household appliance; circuit breakers; single-family residential luminaires; up to five snap switches, dimmers, receptacle outlets, thermostats, heating elements, luminaire ballasts with an exact same ballast; component(s) of electric signs, outline lighting, or skeleton neon tubing when replaced on-site by an appropriate electrical contractor and when the sign, outline lighting or skeleton neon tubing electrical system is not modified; one ten horsepower or smaller motor.

For the purposes of this section, "circuit breaker" means a circuit breaker that is used to provide overcurrent protection only for a branch circuit, as defined in NEC 100.
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I believe with 30 amp 120v supply you can have two 20 amp breakers or you can have a 30 amp main and five branch circuits. That said mine has seven. ;)

To upgrade the parallax I think you are best to just replace the entire panel. You really want power go right to 50 amp service. You just need a new cord and new romex rated 50 amps to connect the cord inlet to the new panel. Not difficult if you have access.

It would be less difficult and costly to just add a couple more breakers using a breaker box.

Unless I remove AC (Air conditioning) which is rarely used and uses a dual 20 amp breaker. I can add a 5 and 10 amp breaker using a breaker box or possibly one 10 and one 15 amp breaker.

I could combine the two (freezer and converter) into one breaker but would prefer the converter and freezer have their own separate breakers.

I sometimes use the sheds power strip that the freezer plugs into for other power such as e.g. an electric tool, pressure washer.

However since the AC is rarely used I'll probably use it's 20 amp dual breaker one connection for the coverter the other for the freezer which doesn't use more an 5 amps.

The AC unit I'm thinking of removing and installing a skylight with air vent.

dedicated appliances, fridge, microwave, AC HWH etc. are required to have their own seperate breaker.

My 30 amp rig came from the factory with the microwave and water heater on the same breaker, and the refrigerator is on the same circuit as the power converter and 4 outlets.

95% of NEC code is based on common sense. Where folks go wrong is designing for worst case scenario loading. Then there is the safety factor like avoiding unintentional bootstrap grounding. Problems occur in RV's because unlike a house they are constantly plugged in and unplugged.

Really the only practical way to upgrade is go to 50 amp service, and make the 6300 a sub panel.

road-runner wrote:

dedicated appliances, fridge, microwave, AC HWH etc. are required to have their own seperate breaker.

My 30 amp rig came from the factory with the microwave and water heater on the same breaker, and the refrigerator is on the same circuit as the power converter and 4 outlets.

Unless you have not found it, MOST quality built RV's can have the Water Heater and the Microwave on the one breaker. BUT! That means the OEM has installed a Switch(either manual or automatic) that allows just 1 of those 2 to run. You cannot run both. IF you can, then they made a mistake on build. Doug

PS, just because an RV HAS IT DONE, does not make it correct or safe. THAT is why they have TSB's and Recalls.

The 75 amp converter will pull approx. 1690VA from 120 input when doing 75 amps/14.x output. (that converter has PF of 0.73) So sharing a circuit with the fridge on electric is dubious. It would work if the converter were only doing regular 13.6v work at low amps output.

If you ever go off-grid on whole house inverter, you want to shut off the converter and have the fridge on gas, so that would be easy if they shared. OTOH if the converter has its own breaker it is easy and you can just unplug the fridge 120 outside if it won't stay on gas by itself instead of auto to 120.

With the 7300 converter sharing with receptacles and you want the receptacles to stay live, you can insert a switch on the converter's black wire on its way to the breaker before where it joins the receptacles' black wire at the breaker.

The MW/WH one or the other switch (like in our 5er) trick can be used with anything that shares. Just means "power management" by the "operator". Lots of that when RVing anyway when using high draw appliances (shut off fridge 120 for a couple minutes while making toast eg) if on limited shore power. The more you do that, the fewer extra breakers needed.