DIYGuy
TX, NY and all points in between.
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As long as you can guarantee that the two 15amp 110v sockets come from the L1 and L2 legs of the power feed, that's a working schematic.
Not something I'd ever allow to be plugged in at my house, but a working schematic.
Why?, Because you're using a single 14 ga. neutral for two legs.
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strollin
San Martin, CA
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murry1946 wrote:Campground has only 15 AMP service, if I use more than T.V. and lights the campground breaker kicks out. Now my question is. Can I use two 15 AMP plug ins and run them to gether to the power cord from trailer (30 Amp) I was told this is possible but would like to know how exactly this can be done. Help is greatly appreciated.
Many posters seem to have missed the "more than" part of your statement. I'm assuming you mean than you're ok running TV and lights but when you try to run your AC or microwave the breaker is tripping.
While you can't combine 15A circuits easily, you might be able to split things off in the RV and plug them into separate 15A outlets (each on a different breaker). For instance, the converter and fridge on my TT plug into 110V outlets so it would be very easy to unplug both of those items and plug them into a separate extension cord and plug that into a different 15A circuit than the rest of the RV is plugged in to. Using this method you probably still wouldn't be able to run the AC though since most ACs require more than 15A.
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wgriswold
Lake Tahoe
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All this makes sense to me. If you combine two legs of the home circuit you get 240V because the two legs are out of phase and the amplitudes (voltages) add.
I have a related question that I have been thinking about for some time. Honda sells a kit that combines the output of two generators to double the amp output. Some people have made a simple homemade device to accomplish the same thing. How are they sure that the phases of the two generators are in the proper relationship to one another to get 120V? What is the proper relationship? Obviously I know just enough to ask questions.
* This post was
edited 08/01/08 01:20pm by wgriswold *
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wittmeba
Roanoke, Va
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wgriswold wrote:All this makes sense to me. If you combine two legs of the home circuit you get 240V because the two legs are out of phase and the amplitudes (voltages) add.
Not necessarily. True if the legs are oposing. They dont have to be. In your breaker box in your house, every other breaker on each side of the box is on the same line. This is how/why they use adjacent positions for breakers requiring 2 poles for 240V.
You dont know how this pedestal box is wired. My suspicion would be if there is only a pair of 15 amp receptacles, there is only 115V available.
Consider Nick's diagram. The line from the powerplant might be 30 amps on 1 line. Then in the box split into 2-15amp breakers/outlets. Very possible and I would think likely too.
From Nick's post "The technique that the OP was referring to will allow you to combine two circuits but it will not work for him because is TT is 30 amp 120 volt" - the problem is the trailer not the source - he has only 1 plug.
strollin - your suggestion could help. If he is able to run an extension cord for the TV or some other appliances (which essentially isolates the TV from the 30 amp connector of the RV) may solve his problem.
It also appears the pedestal breakers and circuitry may be old and weak. Thats why so little makes the CB trip.
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wittmeba
Roanoke, Va
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wgriswold wrote:I have a related question that I have been thinking about for some time. Honda sells a kit that combines the output of two generators to double the amp output. Some people have made a simple homemade device to accomplish the same thing. How are they sure that the phases of the two generators are in the proper relationship to one another to get 120V? What is the proper relationship? Obviously I know just enough to ask questions. << Good quality to have.
I suspect they would have to employee some cross-over device not only to be sure the lines are correct, but they are in sync with one another too. These are 2 different things. Thats my 30,000 foot view.
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wgriswold
Lake Tahoe
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wittmeba,
Thanks for your reply.
First post: I wasn't very clear in my writing. I meant the two legs that enter the house, not the various legs that comprise the circuits in the house.
Second post: That is exactly my problem. I have seen the wiring of the much cheaper home made connectors and all they do is put output of the generators in parallel to one plug. The Honda part is much more expensive and may do more or may just be a money maker for Honda.
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wittmeba
Roanoke, Va
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wgriswold wrote:That is exactly my problem. I have seen the wiring of the much cheaper home made connectors and all they do is put output of the generators in parallel to one plug. The Honda part is much more expensive and may do more or may just be a money maker for Honda.
It would be very interesting to see the output of each technique. I havent a clue what either may produce.
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Nick Wildwood
Hell California
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DIYGuy wrote:As long as you can guarantee that the two 15amp 110v sockets come from the L1 and L2 legs of the power feed, that's a working schematic.
Not something I'd ever allow to be plugged in at my house, but a working schematic.
Why?, Because you're using a single 14 ga. neutral for two legs.
The common neutral actually has no load on it if it is balanced. You only need one neutral for two hots if the hots are different phase. The return from phase one will go into phase two instead of going to the neutral and the return from phase two will go into phase one. They offset each other. The current doesn't go from positive to negative, it takes a step and turns around, takes a step and turns back around again, thus Alternating Current. The current doesn't have to flow down the neutral if there is an opposing load on the other phase. Tesla's the man!
The old 240 volt receptacles didn't even have a neutral, they only had a ground, but the NEC decided that they needed one to catch escaping electrons or to act as a second ground in case the ground wire was disconnected or severed. In a three phase system you have all three phases on a single common, such as 277 - 600 volt systems at factories and shopping centers.
The Test:
Using a voltage tester stick a probe into the right eyeball of a receptacle. Stick the other probe into the left eye and it should read 120v. Take the probe out of the left eye and stick it in the mouth to test the ground. It should read 120v also. Now take that probe and stick it into the other receptacle's right eye. If it reads 240v then you have your two phases. If it reads 0 volts, then it is the same phase. It may be a different circuit but it is the same phase and can't be used in any kind of combination.
To use said adapter technique, this guy he would need to change out his panel and converter to a 240 volt system.
An easier solution would be to plug the microwave and tv into a separate extention cord as stated previously by other posts. One problem is the Air Cond takes close to the whole 15 amps by itself. The long pigtail from the trailer probably has some voltage drop and gets too hot. Cut the cord shorter and install a new plug. Use the remaining wire to make an extention cord for when it doesn't reach. That might help.
Even better solution: Turn it all off and go enjoy the outdoors.
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sbingham
Payson, AZ
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NOPE. Not without breaking the law - of physics.
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john b
anywhere USA!
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I am suprised that none of the intelligent electrical minded people on here didn't just say NO to trying anything like this!
Also I believe the recommencation of a 14 ga cord to supply a 30 amp unit is way off base also. A 14 ga cord has no use on a rig except to lite the patio lights or some type of auxilary appliance or something like that!
There are some really qualified participants on the subject of electricity on this forum as I read their inserts often to refresh my slightly retired talents in this area.IMHO!!!
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