Newbie! 30 amp to 20 amp converter

Hi Rob,

Welcome to the forums.

RV's almost never use 240 volts.

There are two legs of 120 volts each on a 50 amp rv service

When using an appropriate adapter both legs will be powered.

On a 30 amp RV there is only one leg and it is 120 volts. The adapter simply provides a way to plug into a 'standard' house outlet.

NEVER plug a 30 amp RV into 240 volts or you may let out the magic blue smoke.

I hope this helps.

PS - The magic blue smoke is NOT desirable! lol

Seriously, 50 to 30 and 30 to 20 amp adapters hardly ever go bad with proper use. I’d look elsewhere. Your comment indicates to me you should stop all electrical work on your RV and do a bunch of reading.

30 amp is one leg of 120 volts. No 240 volts in thirty amp rigs.
Yes, you can but 30 to 15/20 amp adapter for use in a standard house hold receptacle.
Adapter

Just how big is your rig? 35'? 30'?

I have a 35' 10-wheel school bus that I manage with a pitiful 15-amp service.

If your duplex outlet has 12-gauge wire you can use a different plug. Called a SPECIFICATION GRADE, like it or not I have never had an issue with consuming 17 or even 20-amps through a 15-amp rated spec receptacle AND plug (Look for Hubbell brand. Go to the hardware store and buy a six inch piece of 12 AWG house wire and use it as a guide. By no means try and use a smaller wire in your receptacle box to feed twenty amps.

DON'T

• Try to use a roof air conditioner
• Use an electric hot water heater
• Use more than a single electric heater
• Use a microwave in conjunction with say a coffeemaker, or other high wattage appliance

You have to be very frugal with with wattage appliances.

You absolutely must get an accurate digital voltage gauge (plug in) and look at it when plugging it or switching on a new load. The maximum load is determined by voltage. When voltage drops to 105 volts that's it. Period. Turn something else off before starting the new load.

Life would be a lot easier if you could arrange to have a 50-amp 240 volt service drop installed. If that's impossible you must plan on major concessions by maxing out on 1/4th the power. You also need to use a bridge wire to connect both incoming L1 and L2 phases together. Get a 100 lb cylinder for gas or even a 250 gallon LPG tank set.

This is a lot of info packed into a tiny space so please re-read it,

As piano said. When an RV is 50 amps it's does have 240 volts in the power center but they feed two banks of 120. In your house panel you have two strips of 120 but the double pole breaker pulls from both strips giving you 240.

The problem with 30 amp RV is that if you run two large draw appliances like the microwave and water heater you are maxing the system out. I have a monitor and see 29 or 30 amps when I'm running the air and the microwave. I don't run two things at a time but have forgotten so I checked the draw.

I have run my ac on a 20 amp circuit with an heavy duty extension cord. You want to be sure that the receptacle and plugs and adapter are all clean and snug.

Before you go far on fixing those circits you may want to check for a hot skin and be sure the basics are in order. You don't know what the last person may have done. You don't want it to burn so no matter if electrical, propane, grinding or welding have a fire extinguisher on hand. Before using the propane appliances and especially before sleeping in it be sure the detectors are new and working.

Welcome to the forum. These old timers in here know everything.

Not really a converter as much as an adapter. Assuming the proper adapter is for the correct plug you will have no issues.

If you somehow are forcing a NEMA TT-30 adapter into your home dryer outlet (NEMA 10-30) you will burn out all the 120v items with 240 volts. About once a month someone posts this and as said above the magic smoke is released.

http://www.myrv.us/electric/Pg/30amp_Service.htm

Everything should work on 20 same as 30. If you try to run ac as Mex said, you will pop breakers.

To repeat, your rv DOES NOT have any 220 volt circuits. If you apply 220 you will burn stuff up.

If you have dead circuits start looking for tripped breakers, etc. Lights not working might be because they are 12 volts so check your battery and charger/ converter function.

On a trailer that old you will probably only have a few 120 outlets. Lights, fans, etc run on 12 volts and will have a separate fuse panel.

Please keep us posted.

I am very glad you ask before you burn up your electronics

THERE ARE NO 220 VOLT CIRCUITS IN YOUR RV!!!

The 30 amp plug (tt30) is rated to 125 or 130 volts MAx it is to be wired at 120 volts.. NO MORE DO NOT wire it for 240 our you will let out the magic smoke from your electronics and some of those boxes cost up to 1,000 to replace..

NOW.. The rules according to Readdy Killowatt

20 amp.. You an use ONE major ticket item provided your batteries are charged (Wait at least 2 hours after plugging in) ONE ITEM. Microwave OR air conditioner OR Water heater NO MORE... You may wish to force the fridge to GAS when using any of the above.. TV's are generally OK. Furnace runs on 12 volts so does not count.

30 amp TWO of the BIG ticket items (Generally) but not Two Air Conditioners.

50 amp.. Now 50 amp is 50 amps at 240 volts divided (4 wires not 3) so you can use all the electricity you can eat.

Space heaters.. There is a video on the RV tips group on facebook about what happens when you use a space heater in an RV.. Now in the video the outlet failed safe.. But I seriously do not recommend using space heaters on standard RV outlets.

Mine are plugged into special 15/20 amp outlets 12ga wire to a single breaker each (one is `15 amp one is 20 you can always use a smaller breaker) no problems but the outlet he had started to melt.

An RV outlet at a state park could have 3 different plug outlets, and you can use all 3 on almost any camper if you have the correct adaptor.

However, the amount of amps that you can use in your camper at one time will depend upon the fuses or breakers between the power source and your camper. The pedestal at the campground will have 15-20 amp plugs, 30 amp plugs, and/or/maybe 50 amp plugs. But all 3 of them are only 110 volts. None of them are wired for 220. Unless you have a household stove/oven/water heater/or cloths dryer in your RV, you will not use 220. Everything in your camper is 110 volt. The number of amps is determined by the main breaker is your breaker box / converter.

As said, you can run pretty much anything on a standard 110 volt 15-20 amp circuit inside your camper, but you may be able to run only 1 "thing" at a time. If the over all usage exceeds the breaker 15 or 20 amp setting, it will simply pop. Turn something off, reset, and it will be fine. For example, running the air conditioner with a hair dryer and the microwave will most assuredly pop a 20 amp breaker.

So, power management inside any RV is simply a way of life. You learn real fast what you can run on electricity all at the same time.

There are adaptors you can purchase that are pretty standard. There are basically 2 types. One is called a "dogbone" and the other is called a "puck"

Below are a couple images of a dogbone and a puck. One is an adapter for 30 to 20 amps (standard RV plug to household plug). The other is a 20 amp to a 30 amp. (Standard household plug to an RV plug).

Notice the pattern of the male plugs. The 20 amp household plugs have the straight flat pins that are parallel with the ground being a round pin.

The RV, 30 amp plug also have 2 flat pins, but are in a V shape and the ground is a round pin. These are designed so the wrong one cannot be plugged into the wrong power supply, especially plugging an RV into a 220 volt system.

Puck 20 household to 30 RV:



Dogbone 30 RV to 20 household:



Depending upon the type of unbilical cord your camper has will determine what you kind of adapters you'll need, if anything.

Some older campers have the normal 20 amp amp male plug. If yours is this way, you don't need anything. Just plug into any household plug.

One thing I made sure of, was to have the right combinations of adaptors to go either direction up to a 50 amp plug, especially considering my 5er is 50 amp.

What is always safe to have are the following:

50 RV to 30 RV Dogbone
Male to female
30 RV to 20 Household Dogbone (or puck)
Male to female

20 household to 30 RV
Male to female
30 RV to 50 RV (If your camper is 50 amp).
Male to female

Here's a photo of a typical RV power supply box found at campgrounds showing all 3 types of plugs: 50 amp, 30 amp, 20 amp.



Remember, all these are 110 volt.

A 50 amp may be 2 legs of 110, but it's still only 110 because of the way they are wired, not 240.

DutchmenSport wrote:

Remember, all these are 110 volt.

A 50 amp may be 2 legs of 110, but it's still only 110 because of the way they are wired, not 240.

Most 50A RVs do not have 240V circuits, but the outlet is very much a 120V/240V split phase outlet, identical to what is used for (newer) electric range installations. There is 240V leg to leg, and you can operate any 240V device with the appropriate plug from a campground socket. If the socket does not have 240V leg to leg it is incorrectly installed.

There are some 50A RVs that do have one or more 240V circuits, most commonly I think for an electric clothes dryer. They are comparatively rare, though.