30/50 amp service how to use 30 and 50 amp wiring changes

I have a 50amp service 5th wheel. This is so that both air conditioners can run at the same time. But to this point I've never plugged into a 50amp service and always use the dogbone adapter to a 30 amp plugin. I need to know if the wiring question I have will actually work.

I just bought an all in one inverter, converter, charger identical to this one. ( https://www.amazon.com/GTSUN-Inverter-Controller-Regulator-Transfer/dp/B00SIUIBMS/ref=sr_1_3?s=automotive&ie=UTF8&qid=1498512904&sr=1-3&keywords=gtsun+3000 )But from the actual manufacturer in China. This specific unit will only handle 30amp 3000Watt. It was not really feasible to go to the higher amperage due to cost, size and weight.  This new unit uses a 3 wire 30amp service without issue and extremely easy to wire into a 30amp RV system.

In my case with the 30 amp dogbone attached. once I'm inside of the trailer passed the 50amp plug, I would cut off the outlet from the wire continuing to the distribution panel. Can I then change back to a 30 amp  3 wire? In the same manner as the outside dogbone changes from 30 to 50 amp?

Then I would use the 30 amp 3 wire going into and out of the new inverter, running back to the point where I cut the outside 50amp service from going to the distribution panel.

At this point I would then change back from a 3 wire and connect to the 4 wire 50 amp service. (again in the manner as used in the dogbone) that will continue on to the distribution panel.

I know I will not have 50 amp service and that is acceptable. I just want to  wire in this device and have my entire trailer have A/c current power.  I currently have 450 Watts of Solar and intend to go to 900 once this device is put in place. And if there is no sunlight I can always still connect the generator to charge the batteries.

PS I know I need to disable the original changer in the trailer.

Thanks for any help.
Paul

I believe you are way overthinking this!  First, since it is a 30 Amp unit, regardless of the power source, it will only DRAW a max of 30 A, depending on how much draw there is on the other side.  If it is plugged into a 200 Amp, 120V circuit, it will work fine, but never use over 30Amp.

A 100 watt light bulb draws about 1 amp.  If is plugged into a 15 A circuit, it draws 1 A.  If plugged into a 20 A circuit, it draws 1 A.  If plugged into a 50 A circuit, it draws 1 A.

I suggest simply adding a 30A breaker to your panel, and powering the inv/con from there.  It will work on any power supply.

First: Do you have enough batteries to provide 30 amps for any period of time?  I mean that's nearly 300 amps and a pair of GC-2's are only about 210 Amp Hours so you won't want to run A/C on Battery power

Standard RV wiring as best I can do using ASCII

Shore (or generator===== Main panel---breaker---_inverter/charger-----Sub panel

Main panel..... Air Conditioners, Water Heater, Fridge and other BIG TICKET LOADS

Sub panel.... TV's and electronics,, GFCI, and one big item.. the Microwave (it tends to run for only a few mintues)

And that is how you do it.

Grashly,
Yes a 30amp breaker would work, but the shore power, batteries and this device are in the front and the distribution panels at least 30 ft away to run a line. I would prefer not to run that far under the RV. I could also simply put a 30amp plug coming into the RV. and straight to the inv/conv/chrg, but still would need to connect back to the original 4 wire headed to the distribution panel.

Yes  your are correct. I understand that if I plug a one amp device in. No matter what the source amps are it is still only drawing one amp.

I'm simply trying to splice in this device near the front where the incoming power is, my cross over storage (for mounting) and the batteries. I don't have the electrical knowledge if it will cause harm to go from 3 to 4 wire and back again.


John from Detroit.
You might have a good solution using a sub panel. I was trying to change as little as possible.

Right now, no I do  have the battery amp hours to run for very long. But my fridge is residential and on its own inverter. All lights are LED. The only long draw would be a TV is used, The heater if used. The Air Conditioner would be very limited. I truly plan only to run the fan on it. The AC power is for convenience to plug in a hair dryer or a kuerig coffee maker. or cell phone charger. In any place in the RV rather than to a singe outlet or an extension cord from that outlet. I have no intentions of acting like I am plugged into shore power. Just very limited use of if when desired.

Thank you both for the replies.

It sounds like you are just converting to a 30a supply service.
The only issue i could see is that it would be BAD to plug into a standard 50a service because the hot leads are connected together inside. I would change everything before the inverter/charger to be a 30A setup. Or you could add a separate 30a feed and switch the supply to the original panel to be able to choose between 50a or inverter using a transfer switch.

Glen, I think you understand what's in my head. But without changing everything to a 30amp setup to the inv would just the dog bone on the outside plugging into a 30amp service. But Now I like your next suggestion of adding at 30amp service and let the switch box determine which is used. The I can leave the original charger in place, turn it off when using the 30amp and back on when using the 50 amp.
Thanks

pklundell said:

Glen, I think you understand what's in my head. But without changing everything to a 30amp setup to the inv would just the dog bone on the outside plugging into a 30amp service. But Now I like your next suggestion of adding at 30amp service and let the switch box determine which is used. The I can leave the original charger in place, turn it off when using the 30amp and back on when using the 50 amp.
Thanks

Click to expand...

That sounds dangerous. One day you, or someone else, will do it wrong. Also, it would be irresponsible to ever sell that unit.

PKL,

Thanks for the explanation.  Now that I know the reason, it makes sense.

How about simply tapping one side of the 50A power near the front ==> 30A breaker  ==> con/inv?  You still get full 50A X2 to the panel when connected to 50A service, and the lower amps when that is all that is available. The camp breaker prevents overloads.  May be simpler and safer??

Lynx0849,
How would you propose to install this unit?
https://www.amazon.com/GTSUN-Inverter-Controller-Regulator-Transfer/dp/B00SIUIBMS/ref=sr_1_3?s=automotive&ie=UTF8&qid=1498512904&sr=1-3&keywords=gtsun+3000

The 50 amp service is to run both Air Conditioning units. But never run them together.
Thanks

pklundell said:

Lynx0849,
The 50 amp service is to run both Air Conditioning units. But never run them together.
Thanks

Click to expand...

Why can't you run them together? Each one is on a different 50 amp leg.

We ran both air conditioners at the same time when we had 50 amp service for years. Our 7.5KW generator handled both air conditioners just fine.

Nowhere in this discussion has the battery bank for this inverter been mentioned.  3000W takes a LOT of battery amps, i.e. 275 if you hit the 3000 peak.  Even if its just a minute or two, you need a lot of battery capacity to deliver that burst of amps without a severe voltage drop. Even with solar panels active in the sun.

This whole thing seems overly complicated to me. If you are going to rely on a human to manually shut down the onboard charger (I shudder at that!), why not wire a standard RV 30A outlet to the inverter and plug the shore cord w/30A dogbone into it? All the inverters I've ever seen will trip internally if there is an amp overlaod (and several other conditions as well).

pklundell said:

Lynx0849,
How would you propose to install this unit?
https://www.amazon.com/GTSUN-Inverter-Controller-Regulator-Transfer/dp/B00SIUIBMS/ref=sr_1_3?s=automotive&ie=UTF8&qid=1498512904&sr=1-3&keywords=gtsun+3000

The 50 amp service is to run both Air Conditioning units. But never run them together.
Thanks

Click to expand...

You have a 240v split panel in the trailer. You likely have a 12v D.C. System. That inverter uses 24v DC and connects to a 120v system.

The only safe way I could imagine is to install it and its batteries near the shore power connector (more or less). Then install an exterior female 120v 30a connector (NEMA 5-30l) and a male shore power with a a disconnect and make up a custom version of the 30 to 50a dogbone to connect it to your shore power connector. This way, when you unplug it, the trailer wiring is stock and as safe as factory.

YOU may intend to only run one AC at a time but Murphy says someone will turn em both on. The factory 50a is so all AC appliances may be run whenever.

Now that I wrote all that, I am convinced I would not try to do what you want with the parts you propose. I can't think of a safe way to do it.

OK, I think this is they way that I see you all telling me. And yes probably the best.
Install a new exterior female 120v 30a connector (NEMA 5-30l)  Run this to the new inv/conv/charger. And a dogbone from the 50amp male line to the new 30amp female connector. No problem.

Then install an ATS to decide if power if coming from the 50 amp line or the 30amp line. (ok but someone may say no) (which modifies the original wiring)

Then when the power reaches the distribution panel. I still have to shutdown the original charger if using the 30amp source. (I still see shuddering)

Help for the last two lines guys. I know I'm sounding like an idiot but that's why I'm here asking.
Thank you everyone.

PS

pklundell said:

OK, I think this is they way that I see you all telling me. And yes probably the best.
1.    Install a new exterior female 120v 30a connector (NEMA 5-30l)  Run this to the new inv/conv/charger. And a dogbone from the 50amp male line to the new 30amp female connector. No problem.

2.    Then install an ATS to decide if power if coming from the 50 amp line or the 30amp line. (ok but someone may say no) (which modifies the original wiring)

3.    Then when the power reaches the distribution panel. I still have to shutdown the original charger if using the 30amp source. (I still see shuddering)

Currently only have 4 12volt batteries. But when this is install I'm putting in 4 6volt and another 450 watts of solar.

Help for lines 2 and 3 guys. I know I'm sounding like an idiot but that's why I'm here asking.
Thank you everyone.

Click to expand...

OK, I think this is they way that I see you all telling me. And yes probably the best.
1.    Install a new exterior female 120v 30a connector (NEMA 5-30l)  Run this to the new inv/conv/charger. And a dogbone from the 50amp male line to the new 30amp female connector. No problem.

2.    Then install an ATS to decide if power if coming from the 50 amp line or the 30amp line. (ok but someone may say no) (which modifies the original wiring)

3.    Then when the power reaches the distribution panel. I still have to shutdown the original charger if using the 30amp source. (I still see shuddering)

Do you have suggestions for me?

Currently only have 4 12volt batteries. But when this is install I'm putting in 4 6volt and another 450 watts of solar.