Power connection

Dtaylor wrote:

Bumpyroad wrote:
that is one reason that based on somebody's suggestion here, built my own adapter with a 50 amp male plug and two 30 amp female outlets. then I could pick the side that had the best current.
bumpy

Can you show how that works/how to construct it

well I bought two 30 amp female pigtails, I think they are called, and one male 50 amper connected them together in a standard large square aluminum outdoor box. the hard part was bending/twisting/connecting those huge wires with wire nuts, etc. in the box. when I was done I injected some foam insulating stuff to keep things from moving around after I dipped all of my connections in liquid wire insulation.
I didn't take pictures during building it so can't show those.
I'm sure one of our more handy members can put together a diagram.
you can sort of visualize it from RoyB's diagram, but exchange a 30 where he has a 50 amper.

bumpy

Bumpyroad wrote:
that is one reason that based on somebody's suggestion here, built my own adapter with a 50 amp male plug and two 30 amp female outlets. then I could pick the side that had the best current.
bumpy

Can you show how that works/how to construct it

that is one reason that based on somebody's suggestion here, built my own adapter with a 50 amp male plug and two 30 amp female outlets. then I could pick the side that had the best current.
bumpy

Here is my take on this subject...

This is a typical camp ground pedestal wiring diagram.


This is a typical RV50A MALE to RV30A FEMALE DOGBONE adapter


This is a schematic of the typical RV50A MALE to RV30A FEMALE adapter


When using the RV50A MALE to RV30A FEMALE Adapter plugged into the camp ground pedestal you can see the connections being made to 120VAC LINE VOLTAGE is the same for wired RV30A FEMALE connector in the pedestal diagram.

The difference being one is protected by a 30AMP Circuit Breaker and the other one using the RV50A - RV30A adapter is using a 50AMP Circuit Breaker.

My take is the 30A trailer is properly protected by any overloads in excess of the 30AMP Circuit Breaker installed in the trailer Power Distribution Panel.

The issue being discussed here is what happens to the long 25-50 foot 30AMP Shore Power Cable which is now being fed with a 50AMP 120VAC source. Any overloads more than 30AMP in the trailer will only trip the trailer 30AMP circuit breaker and not the 50AMP circuit breaker in the camp ground pedestal.

Is this a dangerous situation or not. I am pretty sure both 30AMP and 50AMP Shore Power Cables both have 10 GAUGE wire sizes being used. Since the trailer 30AMP Circuit Breaker has tripped there will be no load on the 30A Shore Power cable being used. Only a rare short in the 10-GAUGE cable wires of the 30AMP shore power cable between the trailer and the camp ground pedestal would trip the 50AMP breaker. This rare event would also be possible if the trailer was a 50AMP trailer using the same 10-GAUGE wire sized 50AMP Shore Power Cable. I would imagine the 50AMP Trailer Power distribution panel 50AMP breaker would trip before the camp ground 50AMP Circuit Breaker as well... It seems to be the same circumstances of events to me.

I don't see any electrical problems here of using the RV50A to RV30A Adapter with the 30AMP Shore Power Cable plugged into it causing any problems.

Just my thoughts on the subject here. I do this all the time as well at the camp grounds when I start to hook up to the 30AMP service and see a real bad looking receptacle. I will use the 50AMP Service using an appropriate RV50A to 30A adapter.

Roy Ken

Bumpyroad wrote:
does anybody see a potential problem with the 30 amp RV cord hooked to a 50 amp supply incase of short, excessive draw before the RV 30 amp breaker, etc.?
bumpy

If you are cutting firewood with a ax to close to the cord, or the lawnmowing crew runs over your cord, it will trip either the 50 or 30 amp cord equally fast.

The 30 amp breaker inside the RV will protect the #10 gauge cord from being overheated due to to many amps. #10 wire will not decompose at 32 amps, but rather is actually rated at 40 amps, however at that amperage will get rather warm, and the insulation can deterioate over time. Thus the NEC code requirement to have a maximum fuse size of 30 amps for #10 wire.

NEC does allow a "25 foot rule" where a conductor does not need to have fuse protection for it's size - IF there is overload protection within 25 feet of the time the wire size changes.

Thus a #10 wire can be connected to #000 wires protected at 150 amps safely, IF there is a overload protection within 25 feet of where the #10 wire is connected to the larger wire. The 30 amp circuit breaker that is factory installed in every 30 amp equippend RV is meeting that code requirement. (providing you are not using a 50' extension cord or something else is going on.).

Fred.

Likewise use the 50 amp connection.

Bumpy...........the power cord, rated at 30 Amperes,
IS overprotected by the 50 Ampere breaker. But, there
is little chance of an overcurrent (between 30 and 50
Amperes) IN the power cord. Your RV is protected by
your incoming 30 Ampere circuit breaker.

Dtaylor wrote:
The thread about hot power cord got me thinking.
My TT is 30amp service. If the site I have has a 50amp connection, I use a 50>30amp adaptor and use the 50amp. Is that what you do, or, do you just use the 30amp??

Normally I find the 50 amp plug has not been overloaded, and in general is in better condition, so I use my 50 to 30 amp adapter and the 50 amp plug.

Once the 30 amp was so bad, I had to find my 50 to 30 amp adapter, and the voltage had been 105 volts with the A/C running, but improved to 113 volts with the A/C on once I found the adapter and plugged into the 50 amp receptacle.

So yes I use the 50 amp plug when there is one.

Your RV will be limited to only 30 amps by the main breaker in your RV circuit breaker panel.

Fred.

does anybody see a potential problem with the 30 amp RV cord hooked to a 50 amp supply incase of short, excessive draw before the RV 30 amp breaker, etc.?
bumpy