The Elusive 30-to-20-Amp Adapter and More Power

manyman297

My generator is a Westinghouse iGen2500. It has a 20 amp outlet so I figured I could maximize my amperage by finding a 30 amp -> 20 amp adapter. 

Turns out they’re hard to find. Ended up finding one on Amazon and now I can squeeze every bit of available power out of our generator. 

This got me thinking about other people having issues running their AC on certain generators. The go-to adapter is always the 30 amp to 15 amp. Readily available everywhere but you’re missing out on 5 amps of additional power. That 15 amp adapter could be the Achilles heel in your power chain. If your generator has a 20 amp plug try using a 20 amp adapter and you might find that your AC runs just fine.

Sharon_is_SAM

Please post a link to the adapter.  

Dutch061

I believe that the using a 20 Amp adapter VS a 15 Amp adapter on the outlet will result in a net change of ZERO Amps. The 2200 "running watts" is available either way, the generator isn't smart enough to know if it is a 15 Amp cord cap or a 20 Amp cord cap that is plugged in. In addition, the surface area of the cord cap (15 Amp VS 20 Amp) is the same. So no benefits with a 20 Amp to 30 Amp adapter VS a 15 Amp to 30 Amp adapter. 

The difference is that the generator will "accept a 20 Amp cord cap" from higher current draw appliances. 

Brad

ScottG

The adapter only allows you to connect plugs and receptacles of different configurations. It has no bearing on how many amps can be delivered from the generator's receptacle.

The only reason you would need a 30A --> 20A adapter would be if you were trying to plug your 30A RV power cord into a receptacle designed only for a 20A plug. In the vast majority of cases, 20A receptacles will accept 15A or 20A plugs, and will be able to deliver 20A in either case.

For more info, check out my comment in this discussion.  

manyman297

Sharon_is_SAM said:

Please post a link to the adapter.  

Currently unavailable but here’s the link:

Parkworld 692347 Generator 20 AMP to RV 30A Power Adapter 3-Prong Generator 5-20P Male Plug to RV TT-30R Female Receptacle https://www.amazon.com/dp/B01LVVD2IM/ref=cm_sw_r_cp_api_glt_fabc_V9E9F1M2KT2C3NWS5RY2?_encoding=UTF8&psc=1

manyman297

Thanks for the info. I assumed 20 amp outlets needed the 20 amp plug in order to get the full 20 amps of available power. You guys are right though in that the “gauge” of the plugs appears the same. 

If you can get 20 amps using a 15 amp adapter then why are there 20 amp specific plugs? Maybe this is why these are hard to find…there’s no point in using them?

My thinking was that having that 20 amp adapter would allow the max amount of power needed for that initial surge from the AC. 

ScottG

You don't see standard 20A outlets (below right) very often. I suspect they would be used mostly in commercial/industrial applications as dedicated receptacles for power-hungry equipment having a 20A plug.

Much more common is the 20A "T slot" outlet (below middle) which will accept both 15A and (much rarer) 20A plugs.

The most important thing is that any outlet designed to accept a 20A plug must be on a circuit with a minimum of 12g wire protected by a 20A breaker. Ultimately the wire size and circuit protection is what will determine the capacity of the circuit.

In your case, the capacity of your generator is also a factor. Since Amps = Watts/Volts, a 2500W generator providing 125V can only deliver a maximum of just over 20A. 

manyman297

Thanks @ScottG

This is interesting because I have a 20amp circuit for my garage. The GFCI outlet that runs from the main panel is a T slot but the rest of the run is typical 15 amp outlets BUT all of the wiring is 12 gauge. 

So it sounds like in order to get the max amount of watts out of the generator, the 20 amp adapter needs to be used, correct?

ScottG

@manyman297, while you should never put a 20A outlet (including a T slot) on a circuit rated for only 15A, it's fine to put a 15A outlet on a circuit rated for 20A. In fact, it's done all the time since code requires that certain circuits in a home are 20A, but very few devices in a normal home have a 20A plug.

The answer to your specific question about needing the adapter depends on how your generator is configured. Is your 20A outlet capable of accepting a regular old 15A plug? If so, just plug up with your regular old 30A --> 15A adapter and you will still have the full 20A available.

If not, report back and we'll go from there. (A clear photo of your generator's outlets would be helpful, if possible.) 

manyman297

My generator does have the t-slot outlet (15 and 20 amp).

ScottG

Then you are fine--you do not need the adapter you linked to above. You could use it, but it won't make a bit of difference in the amount of available power.

I believe your generator has 2500 peak watts, but is only rated for 2200 running watts. Practically speaking, that means you only have about 18A to work with anyway.

manyman297

Awesome. Thanks for the info!

ScottG

You are welcome. Camp on and enjoy!