30amp/30amp to 50amp plug

[twinboat]

Originally Posted by EngMarc

Sorry it didn't make sense to you.



I used it to have 30a worth of 220v access at locations where there wasn't a 50a 220v four prong plug.



I basically converted a 30a NEMATT--30 (three prong 220v) commonly called a dryer plug to a NEMA14-50 50a 220v receptacle so I could plug in a 50a plug.



Yes it is true if you try to draw more than 30a the source breaker will likely blow. I just kept my draw down to around 25a as a precaution since some breakers are not continuous duty so they only can withstand full 30a draw for short periods of time.



If this still doesn't make sense message me or respond with specific questions and I'll do my best to answer.

Doing what you were doing put current on the ground conductor. The ground is never designed to carry current. Many times it's a lighter gauge then the hot legs and neutral.

[LETMGROW]

If I was the OP I would do one of two things.
#1) Have your friend send you a diagram of the pedestal wiring.
#2) Wait until you get there and do your own testing of the pedestal

Then, if it's necessary come back here and ask your original question or contact an electrician.
Otherwise you may want to have a fire department and a salvage buyer on standby when you plug in. (Wear safety glasses when you do)

[bigb56]

Originally Posted by Old Scout

EngMarc--curious as to where you would get the neutral for your adaptor...typical, the old- style drier plug has two hots, a ground, but no neutral--dont think a lot of newer surge equipment probably wont like that?

No, a 3 wire clothes dryer circuit is two hots and a neutral, or grounded conductor, not two hots and a ground. The ground shares the neutral. To do this to code, a service entrance type cable was required which has two hots and a unilateral grounded conductor. By definition a grounded conductor is the intentionally grounded conductor at the service, which is also bonded to the earth grounding system. Some refer to it as the neutral, NEC calls it the grounded conductor. So the 3 wire dryer circuit essentially is an extension of the main service and shares neutral and ground just like your main incoming service does. The grounded conductor differs from the grounding conductor, two different animals which become one at the point of service.

Some 3 wire dryers were improperly wired with 10/2 w/ground which was never legal as it places current on an un-insulated conductor.

Another violation was wiring a 3 wire range or dryer from a sub panel, this was not allowed, it had to originate at the service, although this was also violated often.

Using a 3 wire dryer circuit for a 4 wire hookup would be a violation but as far as the EMS or surge protector it will not know the difference, everything will look normal as it is no different than a 4 wire circuit connected directly to the service.

[bigb56]

Here is a diagram showing the 3 wire dryer, note two hots and a neutral with the bond to the cabinet thus utilizing the "neutral" for grounding. Electric dryers need a neutral for the motor and the timer, only the heating elements are 240 volts.

[Ramrod]

Originally Posted by DKRITTER

My sincere, sincere, sincere apologies for the wording in my original post. When I looked at it, it made perfect sense to me. I guess I'm a little different.


Let's kinda start over.

Like I said in the origanal post "I am looking for any recommendations for a 30/30amp male to 50amp female adapter." before we go any farther this is exactly what I am looking for this is for 2 110v 30amp pedestals that are back to back going to a 50amp/50amp 110v female plug. I know I will only be able to get 30amps out of each side. The picture above is worth a thousand words.

This has nothing to do with welders or dryers or 220v plugs.

My friend many years ago had an electrician and a plumber put in the ability to hook up as many as six RV's. There are 6 pedestals 2 each back to back and one water hookup and one sewer hookup. Is this the right way, no but it woks fine and it's free. Usually the most there are 1, 2 maybe 3 RV's so it in reality works out.

Last year it was wonderful with the exception of late afternoons. The eastern plains of Colorado gets hot in the afternoon. So every afternoon I'd go shut off the 30amp breaker (I had a 30 to 50amp adapter) off and fire up the generator so I could run multiple a/c's. After sunset I'd turn off the generator and go down and flip the breaker back on knowing it would be what we call the "or switch". By that I knew I could run 1 a/c or the microwave or a hair dryer or a coffee pot or, or, or and on and on. Certainly not the best solution but it worked.

My friend offered to run a new 50amp plug to the parking area but I said that's to costly. His panel was pretty well full so he would need a new one, plus running a new line to the parking area and a new pedestal was in my opinion to much.

The adapter above is exactly what I am looking for. I used something like this in Raton NM at an older park last year and it met our needs.

Since my friend has pedestals that are back to back I can plug each side into the 2 110v 30amp plug pedestals and have 110V 30/30amp female plug, that I can plug my RV in would solve my afternoon dilemma by being able to run 2 a/c's at the same time.

I am looking for either positive or negative recommendations on any specific brands.

I have used that type of adapter before. Plug 1 leg into the 30 amp plug then plug the other (with a 30 to 20 adapter) into the GFI plug on the pedestal. Be careful to check polarity first. Now you can run 2 A/C until at the same time.
Some campgrounds don’t allow you to use extra electricity that way. Good luck.

[twinboat]

Originally Posted by Ramrod

I have used that type of adapter before. Plug 1 leg into the 30 amp plug then plug the other (with a 30 to 20 adapter) into the GFI plug on the pedestal. Be careful to check polarity first. Now you can run 2 A/C until at the same time.

Some campgrounds don’t allow you to use extra electricity that way. Good luck.

Not sure how you did that, the adaptor will trip the 20 amp GFCI as soon as you use power.
That's even marked on the packaging.

Some of the neutral current will bypass the GFCI thru the 30 amp connection.

GFCIs monitor hot and neutral. If not equal, they trip.

[David-n-BJ]

Originally Posted by Old-Biscuit

Besides....OP is going to use Dual 30A to 50A adapter like the one pictured so while at his friends place he can plug into TWO 30A Receptacles to feed his 50A RV

Actually, he will have 60 amps to feed his 100 amp RV.
Unless the 2 - 30s are different phase, which is possible but unlikely.

If the 2 - 30s back to back are on different phases, then it wouldn't take much to wire in a single 50 at the pedestal for his RV without needing to run new lines (may have to put in larger breakers at the main electrical panel though or else he will have 2- 30 amp circuits instead of the 2-50s).

As it sits, that adapter, if both boxes are on the same circuit/phase and he tries running everything in the RV, it should blow the breakers on that circuit. In fact, depending on how the RV is wired, there is a potential for damage to the RV.

Whether this will work or not depends entirely on how the outlets are wired. If from the same leg or phase, at best it is 30/30 for a 50/50 RV (60 amps at 120v for a 50 amp @ 240v) Or simplified, 30 amps @ 120 volts for his 50 amp @ 240 volts RV.

If they are different legs/phases then it would be 30 amp 240 for his 50 amp 240 RV.

And there is potential for damage in his friend's electrical panel. As others have pointed out, if both are on the same leg, that is 60 amps back at the panel for what could be a single 30 amp breaker. It won't likely trip at the RV connection because breakers there would be for each outlet, but back at the box there is a potential for one breaker to feed both pedestals... which would trip. Constantly.

But if each 30 is on its own breaker, and they are on separate legs/phases then he could see the 30 amp / 30 amp for his 50 amp/50 amp RV. Which would blow the breaker at the pedestal due when "overloaded".

This isn't a matter of what brand is best, it is a matter of how is the pedestal wired.

The pedestal I have wired in for my motorhome (30 amp) is wired for a 20 amp duplex, 30 amp RV and 50 amp RV, with a 50 amp breaker on each leg.
Simplified/Clarified that is 20amp/120volt, 30amp/120volt, and 50amp/240 volts.

I am also concerned about his friend's breaker box. 6 - 30 amp pedestals if wired correctly.. there is 180 amp potential in his 200 amp panel. If all 6 had RVs running their AC, he could easily trip the mains in his house panel.
An electrician might have wired all this for him, but they shouldn't have added 6 30 amp circuits into a house 200 amp panel.
*200 amp panel will have 2 - 100 amp mains, or in an older panel it is possible to see 4-50 amp mains.
Hopefully his friend either upgraded to a 400 amp panel or had a second 200 amp panel installed for the pedestals.

In any case, using the adapter there will be be a maximum of 60 amps for the 100 amp RV.

[bigb56]

Originally Posted by David-n-BJ

I am also concerned about his friend's breaker box. 6 - 30 amp pedestals if wired correctly.. there is 180 amp potential in his 200 amp panel. If all 6 had RVs running their AC, he could easily trip the mains in his house panel.
An electrician might have wired all this for him, but they shouldn't have added 6 30 amp circuits into a house 200 amp panel.
*200 amp panel will have 2 - 100 amp mains, or in an older panel it is possible to see 4-50 amp mains.
Hopefully his friend either upgraded to a 400 amp panel or had a second 200 amp panel installed for the pedestals.

How can you know the setup described needs a 400 amp service from where you are?
Service sizes are determined by load calculations, not speculation, and multiple loads are calculated with load diversity in mind using demand factors. Further, a 200 amp panel at 240 volts is worth 48KVA, while six 30 amp 120 volt loads can only use 21.6 KVA if fully maxed out (which is highly unlikely) which is less than half the capacity of a 200 amp service leaving more than half (110 amps) for the "cottage" even without using demand factors. Sure if the "cottage" is 4,000 square feet maybe then, but we don't have that information so there is no way to make a call like that from our keyboards.

[ac7nj]

I’m not sure what you want to do here. There is more than one 50 amp plug. A 3 prong will likely 220 VAC your RV is not able to use a single pole 220. A different NMEA configuration is a 4 prong plug 2 hot leads a common and a ground. Your 50 amp RV uses both hot leads separately 120 VAC each. The 2 hot leads are not the same phase so putting them together makes 220 again. Most the dogbone adapters are made to isolate the hot leads and still power both sides of your AC distribution panel.
I hope this helps

[twinboat]

Originally Posted by ac7nj

I’m not sure what you want to do here. There is more than one 50 amp plug. A 3 prong will likely 220 VAC your RV is not able to use a single pole 220. A different NMEA configuration is a 4 prong plug 2 hot leads a common and a ground. Your 50 amp RV uses both hot leads separately 120 VAC each. The 2 hot leads are not the same phase so putting them together makes 220 again. Most the dogbone adapters are made to isolate the hot leads and still power both sides of your AC distribution panel.

I hope this helps

No, not at all. The adaptor in question has 2 30 amp, 120 volt plugs going to a 50 amp 120/240 volt outlet.

Only one 50 amp outlet no 50 amp plugs.

[Ramrod]

Originally Posted by twinboat

Not sure how you did that, the adaptor will trip the 20 amp GFCI as soon as you use power.
That's even marked on the packaging.

Some of the neutral current will bypass the GFCI thru the 30 amp connection.

GFCIs monitor hot and neutral. If not equal, they trip.

Sorry your right
You will also need an (old fashioned) 3 prong to 2 prong adapter to trick the GFI.

[bigb56]

Originally Posted by Ramrod

Sorry your right
You will also need an (old fashioned) 3 prong to 2 prong adapter to trick the GFI.

How so? A GFCI does not use the ground wire for anything except the self test or button test. It has nothing to do with how it monitors current flow or how it trips on imbalance, it still does it's job without a ground and functions the same with or without a ground, except for the test function. A cheater can prevent a GFCI from tripping if there is a ground fault in the connected load, but only because it stops the path for current to return on the ground wire thus eliminating the imbalance, provided there are no other alternate paths for the ground fault to flow on. Plus, "lifting" the ground to prevent a GFCI from tripping on a ground fault is dangerous and has killed people, mainly in the music industry and one fatal incident I remember in particular was in a church where the GFCI that the PA system was plugged into kept tripping so they used a cheater and then proceeded to climb into the water for a baptismal while holding the metal microphone and 2 people died.

[bradvoorhees]

Originally Posted by DKRITTER

Our Dutch Star has a 50amp plug.

I am looking for any recommendations for a 30/30amp male to 50amp female adapter.

We are going to a friends this summer and he has 30amp hook ups and I have done a search and have found many adapters that will fit the bill.

I'm looking for either positive or negative information on specific brands.


TIA

I have an adapter that connects to my 50 amp power cord then splits to a 30 amp and a 15/20 amp. I think this adapter would suffice for what you need.

[twinboat]

Originally Posted by bradvoorhees

I have an adapter that connects to my 50 amp power cord then splits to a 30 amp and a 15/20 amp. I think this adapter would suffice for what you need.

Your adaptor will not work in a GFCI protected 15/20 amp outlet.