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Topic: 30 to 50 amp adapter

Posted By: cross country on 10/08/15 11:17am

30 amp motor home plug has one hot leg, one neutral and a ground. A 50 amp plug has 4, 2 hot legs, a neutral and a ground.

When you have a dog bone style adapter, 30 at the pedestal to the 50 amp motor home plug, are both hot legs on the 50 amp side wired with the one hot from the 30 amp plug?

Another related question; I have a voltage regulator rated for 50 amps. using a 30 amp plug at the pedestal to the regulator "in" side which has a ground, neutral and hot leg position.

The "out" going positions are similar to the "in" with only 3 positions however the 3 wires coming out must wire a 4 position 50 amp plug (the power cord from the motor home) Conversely, the 4 wire 50 amp cord must be wired into the 3 position regulator.

Question, which wire from the 4 wire cord is left out? I'm leaning toward putting both "hot" wires from the cord on the one "hot" position on the "out" side of the regulator.

Now I did this before without a question as I cut a dog bone in half and used both ends to hook up the regulator. This time wanting to improve the set up, I have used 30 amp 3 wire, and 50 amp 4 wire with appropriate reusable plug ends.

Thanks very much. Tom



Mary and Tom '86 Crosscountry Sportscoach
2000 Foretravel U320 4210



Posted By: RoyB on 10/08/15 11:55am

The 30A(M) to 50A(F) RV adapter should have the HOT wires jumpered to operate both 50A ZONES in your trailer... You will have to watch what high wattage items you have ON at the same time otherwise the 30AMP BREAKER at the SHORE POWER PEDESTAL will trip on you...

[image]

[image]
GOOGLE IMAGES

Roy Ken


Posted By: DrewE on 10/08/15 12:04pm

The standard 30A male to 50A female RV adapter does wire the hot line to both hots of the 50A socket.

Is your voltage regulator a 120V or a 240V regulator? I'm guessing it's a 120V regulator, since you seem to be using it as such presently. If so, you'd wire the hot input to one of the legs of the 50A plug (or the only hot of a 30A plug), and the hot output to both of the 50A legs. Note, though, that when connected to a 50A circuit, it would limit your power consumption to half of what you would otherwise be able to use--you have a 50A 120V circuit rather than a 50A 120/240V circuit.

Do not connect the two hots together on the input side of the regulator; that would be a dead short, and instantly pop the breaker on the pedestal (or, if it doesn't pop, do much worse things). I suspect you already recognize and understand that.






Posted By: Ed_Gee on 10/08/15 04:05pm

It is my understanding the many, if not most, shore power pedestals are wired such that the two hot legs on the 50Amp jack are out of phase with each other. If this is the case, it would be a serious problem ( e.g. Short circuit ) to have the two pins on the 50amp plug of an adapter cable wired together. Am I missing something?


Ed - on the Central Oregon coast
2018 Winnebago Fuse 23A
Scion xA toad


Posted By: RoyB on 10/08/15 04:23pm

This is how the RV PEDESTALS are wired up and being used...
[image]

Granted if you tie those two HOTS together from the SHORE POWER SIDE SOURCE it would be bad...

However tieing the two hots together feeding the RV 120VAC Distribution PANEL from a 30A single phase source is not going to do any harm... The 30A side at the pedestal only has ONE LEAD HOT... You are just sending this same hot lead to two locations. If you are using an applicance that is wired for 220VAC then the 30A-50A RV adapter will not work for that one appliance. It is only sending 120VAC to the RV Distribution Panel.

Read up DMBRUSS Electrical adapters on-line
DMBRUSS RV ADAPTERS ARTICLES

Roy Ken


Posted By: Ed_Gee on 10/08/15 07:31pm

Roy, my bad. I was thinking of the 50A down to 30A adapter, not the 30A to 50A adapter, which was shown prior to your post above. You must admit, shorting the two hot pins on a 50A to 30A adapter plug would be a very bad idea. I neglected to notice the difference under discussion. I have and use both types of adapters.


Posted By: wa8yxm on 10/09/15 10:28am

Original questions hard to read but.

Assuming you have a 50 amp RV (if you have a 30 amp skip to Assuming you have a 30 amp RV)

The adapter you plug into the 30 amp box feeds BOTH sides (hot leads) on the 50 amp outlet from the HOT lead (one hopes) Neutral and ground are passed through.

Your Surge guard (50 amps) does not care if the two legs are the same or different so it works normally either way and passes power through exactly as it does when plugged into 50 amps.. In fact one function of it works BETTER on 30 amp but .. Well,, This is not a proble (obviously).


If you have a 30 amp RV

Then the adapter picks a side, Depending on who made it it will be either the left or right (This assumes neutral is at the top) side, but in truth, NORMALLY it does not matter.. Again the surge guard works exactly as it would on a 30 amp site.

NOTE: I do recommend having 2 adapters if you have a 30 amp rig.. one which passes the Right side through and leave the left disconnected, and one that works the other way around.. From time to time (Rare but it happens) one might work better than the other.

Plus. with 30 amp Rigs.. A spare adapter (and a spare plug) are recommended anyway.


Home is where I park it.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times



Posted By: Dutch_12078 on 10/09/15 12:02pm

wa8yxm wrote:


NOTE: I do recommend having 2 adapters if you have a 30 amp rig.. one which passes the Right side through and leave the left disconnected, and one that works the other way around.. From time to time (Rare but it happens) one might work better than the other.

Plus. with 30 amp Rigs.. A spare adapter (and a spare plug) are recommended anyway.

You should have seen the strange looks I got at Camping World a few years ago when I was testing a couple of different brands of adapters with a pocket multi-meter to find one with the opposite leg from the one I already had. [emoticon][emoticon]


Dutch
2001 GBM Landau 34' Class A
F53 chassis, Triton V10, TST TPMS
Bigfoot Automatic Leveling System
2011 Toyota RAV4 4WD/Remco pump
ReadyBrute Elite tow bar/Blue Ox baseplate



Posted By: cross country on 10/12/15 01:06pm

Thank you for the very informative diagrams,comments and resources. It is particularly gratifying when there is agreement concerning high voltage. The result is; 30 amp plug from pedestal (wired with 3 wire to the regulator 3 wire positions.) OUT from the regulator (3 position lugs) and to the 50 amp motor home plug; 4 wires of which the 2 hot leg wires are connected on the one hot position in the regulator and continuing to the 50 amp plug where in the 2 hot wires are connected separately to each hot blade in the plug. Thus we have 30 amp source going in and that single hot wire becoming 2 wires to accommodate each leg side of the 50 amp plug; to the motor home distribution system. And quite obviously will still have only 30 amps going into the motor home. Thanks again. Tom


Posted By: wa8yxm on 10/13/15 11:08am

cross country wrote:

30 amp motor home plug has one hot leg, one neutral and a ground. A 50 amp plug has 4, 2 hot legs, a neutral and a ground.

When you have a dog bone style adapter, 30 at the pedestal to the 50 amp motor home plug, are both hot legs on the 50 amp side wired with the one hot from the 30 amp plug?



Yes, that is exactly how they are supposed to work

Quote:


Another related question; I have a voltage regulator rated for 50 amps. using a 30 amp plug at the pedestal to the regulator "in" side which has a ground, neutral and hot leg position.


I am not sure you are using the word "Regulator" properly but. If the device is designed for a 50 amp RV then the plug should be 4 wire 50 amp same as the RV's shore cord.. you use the dogbone adapter on that plug.. And plug the RV into the "Regulator"s outlet.

The Green (ground wire) is common to everything.

If the "Regulator" has only one hot (Black) one neutral (White) and ground (Green) it is not a 50 amp RV product.

Also what is it.. I'm guessing it's sometime else. But I hate assuming.


Posted By: cross country on 10/18/15 08:58pm

No, it is not an RV product. It is an ECOWISE 50/1 piece of electrical equipment for use in office floors to protect computers and other electronics from low and high voltage.

Common voltage in an RV park in Mazatlan is 133 134 all day everyday. This machine brings it down to 120/119 and it stays there.


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