Making a 50 Amp Splitter

[captain ron]

I have 2 30 amp receptacles on the pole at my bus. I need 50 amp for my dryer. Can any of you tell me how to make a splitter that I can run my dryer and then go back to 30 amp for my bus? Or just make the splitter to use only when I need to use my dryer? There is also a 20 amp plug in for an extension cord, The type with the  -l l  plug.
       

[prevost82]

Hi Ron ... The problem is you need two legs 180 deg apart ... so you'd have to determine are they 2 circuits 180 deg (2 diff legs). If they are then you need to make an adapter that takes your hot legs (2) sepperate to your panel and the join the neutal together with the neutal to panel then join the grounds together to the panel. I made one for 2- 15amps to a 50amp (2-25amps)
Ron

[Stan]

To the best of my knowledge, there is only one way to get 50 amps out of a 30 amp circuit. To do it, the 30 amp circuit has to 249 volts which you can feed into a transformer that has a 240 volt primary and a 120 volt secondary and a rating of at least 6000 VA. Check out a Square D T750D1 from Grainger. If your 30 amp receptacles are both on the same leg, there is no way to get 120 volt 50 amps out of 120 volts 30 amps.

[Sean]

Ron,

If your dryer is really 50-amp, there is no way to do this.

The best you can make out of two 30-amp, 120-volt circuits would be a single, 30-amp 240-volt circuit, amd you can't run 50-amps through it.  Your 30-amp circuits are likely run on #10, or maybe #8 if it's a long run back to the panel.  You need #6 for 50-amps, or #4 for a long run.

Now, if your dryer just happens to be 30-amp, but 240-V, what you really need to do is replace your two 30-amp 120-volt circuits with a single 30-amp, 240-volt circuit.  That requires a breaker change from two single-pole breakers to one double-pole (or handle-tie) breaker.  Running the dryer on two single-poles is unsafe, and also may damage the dryer if one circuit trips without the other.

If you need to run the dryer and the bus from the same circuit(s), the safe thing to do is change to a two-pole breaker, rewire the pedestal to a 30-amp, 240/120-volt circuit (4-wire), and make adapters for both the bus and the dryer.

HTH.

-Sean
http://ourodyssey.blogspot.com

[captain ron]

Sorry guys all I can hear is blah blah blah blah blah. Kinda like talking to the ex-wife. 

I was kinda hoping for "you hook the green wire to the red wire and" You Know. I'm very illiterate when it comes to electric. 2 things I know about electric is if you stick your finger in the socket you'll get shocked and if you don't pay the bill they'll shut it off.

[Sean]

Well, if that's where you are at, then the safest thing to do is to call an electrician.  50 amps of current is plenty enough to kill you at worst.  And there's a whole range of bad things that can happen that are less than that extreme -- such as: all will be well to all external appearances, right up until your dryer, coach, or house bursts into flames.

Without being there to see what you already have, how it's wired, and what you are trying to connect, it is nearly impossible to give you the type of instructions you are seeking.  But we are nothing if not challenged by the nearly impossible on this board.

So, perhaps you can start by giving us the make and model of your dryer, so we can look up what sort of power it requires.

You'll also need to take out your voltmeter, set it on a scale of 250V or more, AC, and stick one lead in the shorter slot on one 30-A receptacle, and the other lead in the shorter slot on the other 30-A receptacle, and tell us whether you get zero, 240, or some other number.  (If the slots on your outlets look the same, you want to measure at the one that is on the left, if the u-shaped ground is at the top).


Let us know the results.

-Sean
http://ourodyssey.blogspot.com

[captain ron]

 Thanks Sean,  I have 114 volts from the ground and hot on the 30 amp plug on the pole. Its the same as you have pictured.

[Sean]

OK, I think I was not clear:

You said (I thought) that you had two of these receptacles on your power pole.  Is that correct?

If so, then what I need you to measure is from the "Hot" on one outlet to the "Hot" on the other outlet.  Then tell me if that's zero, 240, or something else.

-Sean
http://ourodyssey.blogspot.com

[captain ron]

Sorry, Don't know if my volt meter has a 240 volt setting. I'll ask someone in the park to see if they have a better one, although this is a pretty nice one.
I checked it the way you said and have 235.9 volts.

[white-eagle]

Ron,
i have nothing to help you, but i really liked your reply.  i'm with you!  just tell me which side if black and which is green or white.

i just spent 4 hours rewiring my toad lights from the bus which is going from 6 wires to four, so needed adapter, yadda, yadda, yadda.

good luck, and i'm listening in case i need to do the same.

nice job explaining Sean!

[Sean]

OK, Ron, so far so good.  The next question is what make and model of dryer do you have, and can you describe the plug on it (three tangs or four, what shape, etc., or better yet, if it has any numbers stamped into it)?

Also, do I understand you are in an RV park?  If so, are the breakers for these outlets right there on the pedestal, or somewhere else in the park?

-Sean
http://ourodyssey.blogspot.com

[captain ron]

Sean, The dryer is a Whirlpool 3 cycle model# LE4930XKNO  serial# M24820833
the plug has 14-50P stamped on it. it has 4 prongs one round 2 vertical parallel to each other then an upside down L at the bottom.

The breakers are on the pole in the box with the plugs. And yes I'm in a park.

[Sean]

Unfortunately, I was not able to find any specifications for your dryer.

The cord and plug that is on it is definitely a 50-amp, 240-volt cord.  However, most dryers do not come with a cord attached -- that's something that either the installer or consumer adds (the reason for this is that there are several different but common types of receptacles in houses, and some codes required grounded outlets and some did not).

The cord on your dryer, 14-50P, is not common for dryers -- it is more common for electric ranges.  So maybe whoever originally installed the dryer connected it to a range outlet.

We need to find out how much current the dryer really needs.  So I have to ask you to find the "rating plate" (probably near where you found the model and serial numbers), and see how much power it needs.  It should list the power draw either in watts or amps.

Also, find the connection box on the dryer itself for the power cord.  It should be a little cover plate right near where the cord enters the dryer, secured with a screw.  Open that up, and tell me if all four wires are connected to terminals in the dryer, or if the white wire is disconnected.

-Sean
http://ourodyssey.blogspot.com

[Don4107]

Ron, 

Be aware that an adapter that will work where you are now may not work at the next site unless everything checks out the same ie that you do the same tests to find 240vac between the two pole plugs.

Whirlpool only lists 30 amp service for the dryer and does not give actual draw.  I would put it closer to 15 amp guessing that the heating element is closer to 3000 watts.  Larger dryers typically use around 4500 watt elements which would put you near 20 amps.  There should be info on the ID plate about current draw.

[Sean]

Don's reply caused me to re-read your last post.

I see where you wrote that the third tang on your dryer plug is L-shaped.  That would make it a 14-30P, which is a 30-amp plug, which is good news.

(Side note:  If the plug is really marked 14-50P, then it is likely an "interchangeable" plug.  This is made for either 30 or 50 amp applications, and comes with two different tangs, a straight and an "L".  You use whichever one you need when you assemble the plug.  Here's a photo:

)

To run your dryer from the post you have now, you have a couple of choices.  This will be a little long, so stick with me to the end.

First, a disclaimer and a warning:  Trying to assist you like this by remote-control carries with it some risk.  I am not there to observe the actual conditions.  Please, please, if you are at all uncomfortable with or unsure of what you are doing, get some local expert help.  I can't emphasize this enough.  You alone will be responsible for the outcome, since I'm not there -- there is a possibility that you will follow my instructions exactly, and something will still go wrong.

Secondly, you need to be aware that a 240-volt device like your dryer really should have a 240-volt breaker.  Your pedestal now has two individual 120-volt breakers.  To be safe, you should really open the pedestal and replace the two breakers with a double-pole breaker (one handle operates both circuits).  Without this, you could create an unsafe condition if one breaker is on and the other off (either done manually, or because only one side trips).  The breaker you need is probably about $10-$15 at Home Depot, however, without the campground's permission to do so, or someone to shut off power to the pedestal, you might not wish to do this (although it can be done).

OK, on to the fix.  The easy thing to do is to go to Camping World and buy one of these:
http://www.campingworld.com/browse/skus/index.cfm?skunum=25774&src=SRQB

This is a common item that is intended to allow you to plug a 240-volt, 50-amp coach into two 30-amp circuits.  It's $60 at Camping World, but you might find one cheaper at a discount outlet.  You can build this yourself, but you'll likely not save very much, as all the parts together will probably run you $40-$50.

(If you can scrounge parts for it, I will give you the wiring connections.  The parts you need are two 30-amp TT-30P "travel trailer" plugs, several feet of flexible 10-3 cord [10 gauge, 3-conductor] such as from a heavy-duty extension cord, a 4" square metal junction box, a cover for the box with a 2.15"  hole for the receptacle, two strain reliefs that fit in knockouts in the j-box and can secure the 10-3 cords, and a NEMA 14-30R receptacle, which is the one with the four holes, one U-shaped, one L-shaped, and two straight -- it will be marked 14-30R and something like 30-amp, 125/250volts.

Cut two equal lengths of the 10-3 cord.  I recommend no longer than about 3-4' each, but you could get away with as little as a foot or so.  Connect one end of each cord to each of the two plugs.  [Sometimes, you can find the plugs with the cords already on them.]  The green wires go to the round or U-shaped prong.  The blades for the other two wires should be marked either "B" or "X" and "W".  White goes to "W", and black goes to "B" or "X".  If there are no labels, use the picture I posted earlier, or perhaps the screw for the white wire will be silver and for the black will be brass.

The other ends of the two cords go through the strain reliefs and into the J-box.  Here you want to connect both green wires to the U-shaped slot, and both white wires to the L-shaped slot.  Connect one black wire to each straight slot (it does not matter which one goes to which slot.  Assemble the box, receptacle, and cover plate, and secure the strain reliefs.)

If you buy the ready-made box, you will still need to go to Home Depot and buy the NEMA 14-30R receptacle (about $10-$12).  Remove the cover plate/receptacle mount from the adapter box, and replace the 14-50R receptacle that came with it with the new 14-30R receptacle -- the wires go into exactly the same terminals on the new receptacle as on the one you are removing.  Save the old 14-50R receptacle, because you can probably sell the adapter to another RVer when you are done with it if you put back the original receptacle.

Turn off both breakers, plug both 30-amp trailer plugs into the outlets on the pole, then turn both breakers on.  Now measure from each of the straight slots to the L-shaped slot, to be sure they each read ~120v.  Then measure between the two straight slots, should be ~240v.  Measure from the L slot to the U-shaped slot, should be close to zero.

If that all checks out, you should be ready to plug in the dryer and test it.

Let us know how it comes out.

-Sean
http://ourodyssey.blogspot.com