30-amp outlets 3 different connectors?

[Rail_Dawg]

Why do many RV’s have a 30-amp 3-prong outlet that is one prong configuration but the 30-amp shore power may have 3 prongs with a different prong configuration?

Getting a portable 8000k Generac to connect to the RV requires yet another type of 30-amp connector.

Spending some $$$ on adapters just curious why no standardization?

[Gdetrailer]

joebedford wrote:
Question about my generator but it's pertinent to the thread: I have a 5500W generator 120/240V that I use for house backup.

Other than pulling the darn thing apart, is there any way to tell which leg/winding the 120V plugs are on?

I assume the 40A twist lock plug has one pin on one winding and the other on the other so to speak. Not sure about the 120V receptacles though, which I think is the question OP is asking too.

Documentation (hahaha) doesn't say.

Uses both legs and you only get half the gen wattage at 120V on EACH LEG..

Any 120/240 generator splits the output of the two windings (legs)as two separate 120V outputs. Typically these gens will have two side by side 120V duplex outlets.

Each duplex is ONE of the windings and HALF of the 240V wattage..

Cannot combine the 120V outlets or windings to get wattage of the gen on 120 only without major rewirng internally.

If you WANT the full output on 120V then I would recommend looking at the Champion gens, they have models which have a SELECTOR SWITCH which allows you get full gen output on 120V only.

Any other brand you are wasting half the gen output..

[wa8yxm]

The Generator is a 30 amp "TWIST LOCK" and may be 3 or 4 wire the 4 wire versio is a 120/240 volt plug.

The plug for the park is a TT-30 120 volt ONLY

The pair at the RV is a Marinco

You will need only two adapters

A 30-50 RV adapter for sites where the 30 amp outlet is ... not good but there is a very good 50

And a Twist Lock to TT-30

Why The Twist lock on the genny? If you had just a TT-30 there odds are on many generators engine and generator vibration it would quickly fall out. but the TWIST LOCK hangs in there.

[LittleBill]

time2roll wrote:
Is that a GP8000E? Comes with a four prong 30 amp 120/240v service and a few standard home outlets.

That 3 prong adapter will not work. Or generator is something else. Need 240v connector to get 8000 watts out of a generator on 30 amps.

https://www.northerntool.com/shop/toolsGP8000E

yea lets clarify this a bit because this is misleading. That adapter will work just fine for 30amp 120v.

to get 30amps AT 240, you need a 7200 watt generator

a 7200 watt generator will put out 60A at 120V

so to be clear your 8k generator makes more then enough power

using the adapter will you allow you to use all 30 amps of 120v that your trailer needs.

yes your only running on one winding, but its not a big deal, you would still have 30 amps available on the other winding if you wanted to use the 15 amp receptacles or build a splitter box off the 240 twist lock.

[DrewE]

If there are two sets of 120V 15/20A sockets, I'd guess that they're on opposite legs. If you can get access to the back of the panel on the generator relatively easily you could trace out the wires...or measure things with a multimeter, as time2roll suggests.

[time2roll]

Measure the voltage between the hots. 0 is same side, 240 is opposite.

[joebedford]

Question about my generator but it's pertinent to the thread: I have a 5500W generator 120/240V that I use for house backup.

Other than pulling the darn thing apart, is there any way to tell which leg/winding the 120V plugs are on?

I assume the 40A twist lock plug has one pin on one winding and the other on the other so to speak. Not sure about the 120V receptacles though, which I think is the question OP is asking too.

Documentation (hahaha) doesn't say.

[Rail_Dawg]

time2roll wrote:
Yes you can get an adapter but will be pulling from just half the generator. So it becomes 4000 watts and is plenty for a 30 amp RV. Not sure how the mining equipment fits into this. Probably two of the 5-15 outlets come off each side so if you need 120v you are in good shape. A 240v dewatering pump may require the RV to be unplugged or go to low power outlet.

3500w Champion with RV plug


L14-30 to RV30-TT adapter:



https://www.walmart.com/ip/AC-Connectors-RVL1430TT-Generator-4Prong-L14-30P-30Amp-Locking-Plug-to-RV...

That's what I was thinking when I bought the adapter plug... that we could pull 30-amps 120V.

We run the generator for A/C when on a break but then use the gen for other (mining) stuff as needed.

Now if we connect that adapter plug up and run it to the RV you think we still have 120v extra power available at the other 20-amp standard 3-prong outlets?

Appreciate your taking the time to educate. Thought I had it down but there's still some things to learn about this generator.

[time2roll]

Yes you can get an adapter but will be pulling from just half the generator. So it becomes 4000 watts and is plenty for a 30 amp RV. Not sure how the mining equipment fits into this. Probably two of the 5-15 outlets come off each side so if you need 120v you are in good shape. A 240v dewatering pump may require the RV to be unplugged or go to low power outlet.

3500w Champion with RV plug


L14-30 to RV30-TT adapter:



https://www.walmart.com/ip/AC-Connectors-RVL1430TT-Generator-4Prong-L14-30P-30Amp-Locking-Plug-to-RV...

[Rail_Dawg]

time2roll wrote:
Is that a GP8000E? Comes with a four prong 30 amp 120/240v service and a few standard home outlets.

That 3 prong adapter will not work. Or generator is something else. Need 240v connector to get 8000 watts out of a generator on 30 amps.

https://www.northerntool.com/shop/toolsGP8000E

It's a Generac xp8000e but has the same 30amp 4-prong outlet as the GP.

Now you've got me thinking!

I thought I could pull 30amps of 120v off that outlet but now I'll need to do some research to see if it will.

If not then fortunately my A/C has a standard plug so I can run it off one of the standard 20amp plugs in the generator and run the rest of the rig (including battery charge) on the other standard 20 amp plug.

But I need to do some homework on the Generac to see if 120v 30amps can be pulled off that locking receptacle.

In some ways running the A/C off the standard plug is a good thing as I wanted the gen a good 100' from the rig and I have plenty of quality 20 amp extension cord for that.

Buying a 30amp cord of the same length is expensive!

Thanks for your insights on this. Glad to find out issues ahead of time.

[Isaac-1]

ktmrfs wrote:
...
The big question is why didn't the RV industry standarize on the 30A twist lock?

I suspect the RV industry had already standardized on the 30A TT connector when twist locks became popular for light industrial uses (1980's or maybe 1990's)? I also have to wonder if twist lock outlets may not stand up to as many insertion events, an RV park with an active turn over may see a plug insertion event every day on a typical outlet, that is over 1,000 in 3 years.

[time2roll]

Is that a GP8000E? Comes with a four prong 30 amp 120/240v service and a few standard home outlets.

That 3 prong adapter will not work. Or generator is something else. Need 240v connector to get 8000 watts out of a generator on 30 amps.

https://www.northerntool.com/shop/toolsGP8000E

[ktmrfs]

RV 30A is designated for RV use only. the NEMA standard for 120V/30A is a twist lock. So........ RV parks have a 30A RV socket, but most generators and any non RV application has the 30A NEMA twist lock since that is the industry and NEC connection for 30A 120V for everything other than an RV.

Note the "Travel trailer use only" notation on the 30A RV plug.

Now a 30A twist lock to 30A RV adapter is readily available. Try finding a 30A RV to 30A twist lock, I've never seen one.

The big question is why didn't the RV industry standarize on the 30A twist lock?

[MrWizard]

twist lock is standard industrial, does not come loose with movement
very common on large portable generators

RV/TT 30 amp has flat blades at angles, designed for fixed location

[Rail_Dawg]

Dutch_12078 wrote:
Are you referring to the Marinco style twist-lock socket commonly used at the trailer end of the cord versus the TT-30 plug used at the shorepower end? You should only need an adapter for the TT-30 plug to the generator outlet, and that's not very costly.

Generator Plug Adapter for RV Power Cord-30 Amps-3 Prong Twist Lock

Yes that’s the connection.

Just curious why the difference.

Thanks.