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jsmart's avatar
jsmart
Explorer
Jun 01, 2015

30A vs 50A

Just a curious question for all you experts out there, We have a 2002 32V Itasca Sunrise, bought it used, have had it almost 2 years. It has the 30 amp power cord, however, the box the power cord goes into in the lower compartment has a label on it that says "max 50 amp". The electronic control station in the hallway also has indicators for which power source is being used, has light for generator, 20a, 30a and 50a. Is it possible to replace the 30a power cord with a 50a power cord and use 50a power? We have 2 air conditioners and although have never had a problem with power, we do need to watch what we have on at any given time, (i.e., DW can't blow dry her hair while both air conditioners are on). Just a thought.
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  • eXodusRV's avatar
    eXodusRV
    Explorer
    Jul 06, 2015
    jerseyjim wrote:
    EXODUSRV: Sure. I know what breakers are for....and if you trip them, something ain't right. Make all the adapters your want, jury rig all the wiring you want, but the bottom line is 30 amp does one a/c...and 50 does 2 a/cs' and one never has to worry about breakers or anything else.

    And the KEY words (yours) to back me up is "dangerously warm". No need to get even CLOSE to that using 2 a/cs with 50 amps.


    There are two reasons for a tripped breaker, number one, there is something wrong with the wiring or device, here you are right.

    The secondary reason a breaker trips is that you are using too much power. The breaker trips to prevent the wire from overheating.

    Electric supply companies are using gradually overloading wires since many years. The know that most wires are capable of transferring more power then rated when they got the chance to cool down in between.

    The same would be with two A/C Units they are only using a lot off energy while starting (less then 10 seconds) when they are running they don't need a lot.

    With the newer Energy efficient 9000 and 12000 BTU you could probably run even 3 Units of a 30A Service.
  • tropical36's avatar
    tropical36
    Explorer
    Jul 06, 2015
    John & Angela wrote:
    jerseyjim wrote:
    EXODUSRV: Sure. I know what breakers are for....and if you trip them, something ain't right. Make all the adapters your want, jury rig all the wiring you want, but the bottom line is 30 amp does one a/c...and 50 does 2 a/cs' and one never has to worry about breakers or anything else.

    And the KEY words (yours) to back me up is "dangerously warm". No need to get even CLOSE to that using 2 a/cs with 50 amps.


    Just curious. Why would 30 amp not support two AC's. The total current is less than 30 amps. Nothing should get warm. I had a motorhome that had two AC's on 30 amps that had no problem, no warm cords. It used an EMS that insured that both AC's didn't start at the same time but they ran together (both compressors on) with no problems. Current readout was 24 to 26 amps. No jury rigging or adapters.

    Our existing motorhome is 50 amp but we are often on 30 amp. Runs two AC's quite fine. EMS keeps everything under 30 regardless of what you turn on. (it does the power management of devices) Nothing ever gets warm.
    What am I missing.

    Your're not missing anything, except all the unnecessary drama and wouldn't even want a 50amp service on our present coach.
    Having an EMS is the key and to prevent breaker tripping. Older units had selector switches for selecting front or rear ac and only when on shore power, as the gen set handles it easily with it's private rear ac circuit. I did split this rear ac circuit so as to have the choice of running it on it's own dedicated pedestal outlet and something the manuf. should have thought of. Just 15amps or so less that the EMS has to manage and will sometimes allow you to run the microwave without the ac's shedding. A whole lot better when you first pull in and when the heat is really pouring in.
  • jhilley's avatar
    jhilley
    Explorer
    Jul 06, 2015
    30 amp is sufficient for two ACs, however there is not any margin for poor connections and connectors in direct sun light. Just keep an eye on your plugs, receptacles and cables. Make sure connections are tight in the transfer switch, breaker panel and AC wiring. Even with 50 amp, monitor the campground voltage on hot days when they are full.
  • John___Angela's avatar
    John___Angela
    Explorer
    Jul 06, 2015
    jerseyjim wrote:
    EXODUSRV: Sure. I know what breakers are for....and if you trip them, something ain't right. Make all the adapters your want, jury rig all the wiring you want, but the bottom line is 30 amp does one a/c...and 50 does 2 a/cs' and one never has to worry about breakers or anything else.

    And the KEY words (yours) to back me up is "dangerously warm". No need to get even CLOSE to that using 2 a/cs with 50 amps.


    Just curious. Why would 30 amp not support two AC's. The total current is less than 30 amps. Nothing should get warm. I had a motorhome that had two AC's on 30 amps that had no problem, no warm cords. It used an EMS that insured that both AC's didn't start at the same time but they ran together (both compressors on) with no problems. Current readout was 24 to 26 amps. No jury rigging or adapters.

    Our existing motorhome is 50 amp but we are often on 30 amp. Runs two AC's quite fine. EMS keeps everything under 30 regardless of what you turn on. (it does the power management of devices) Nothing ever gets warm.

    What am I missing.
  • Bumpyroad's avatar
    Bumpyroad
    Explorer
    Jul 06, 2015
    jerseyjim wrote:


    And the KEY words (yours) to back me up is "dangerously warm". No need to get even CLOSE to that using 2 a/cs with 50 amps.


    the important KEY words left out were "The wiring used for 30A is usually capable to supply double the amps for at least a couple of hours without getting dangerously warm." you seemed to leave out "without".
    bumpy
  • jerseyjim's avatar
    jerseyjim
    Explorer
    Jul 06, 2015
    EXODUSRV: Sure. I know what breakers are for....and if you trip them, something ain't right. Make all the adapters your want, jury rig all the wiring you want, but the bottom line is 30 amp does one a/c...and 50 does 2 a/cs' and one never has to worry about breakers or anything else.

    And the KEY words (yours) to back me up is "dangerously warm". No need to get even CLOSE to that using 2 a/cs with 50 amps.
  • Bumpyroad's avatar
    Bumpyroad
    Explorer
    Jul 05, 2015
    I made an adapter that plugged into a 50 amp outlet and had two 30 amp pigtails so I could use the side that had the best current.
    bumpy
  • Kayteg1's avatar
    Kayteg1
    Explorer II
    Jul 05, 2015
    Anybody who is considering such project should start with measuring what you have.
    I have about 8 years old, but good quality AC unit at 15,000 btu takes 8 amps while running. It is starting that takes big current.
    I think main issue at most of campgrounds will be voltage drop. Even when lot of campgrounds have 30 and 50 amps posts, the main wiring is not design for holding loads and traveling with plug in meter, I have seen 100V supply more than once.
    That can really run some AC units into trouble.
    Couple of times I was forced to start my AC on inverter power and then switch to shore power.
    Campground wiring under starting load would supply less than 90V
  • Bumpyroad's avatar
    Bumpyroad
    Explorer
    Jul 05, 2015
    eXodusRV wrote:
    jerseyjim wrote:
    The only thing 50 AMP does (vs 30 amp) is let you run BOTH a/c units at the same time. Those that say they run 2 units on 30 amps at the same time, are taking a chance with electrical overload and that can equal a fire. Run both on 20AMP? Hope a fire extinguisher is nearby. IMO a definite recipe for disaster. Again...my opinion.
    I have no idea why any coach company would market a unit with 2 a/c units and give 30 amps. IMO (again) that is not only dangerous but stupid. But then, I've seen new units at RV shows with no electrical outlets in the kitchen! How dumb is that?


    You do know what breakers are for ? Do you ?
    In case you use more then 30A then the breaker trips and you will be there without power.

    It's like in your house, you've got probably 5-10 15A outlets wired to the same 20A breaker. How often due houses burn down because of installed wiring ? rarely ever.

    The wiring used for 30A is usually capable to supply double the amps for at least a couple of hours without getting dangerously warm. Most all RVs burn down because of defective cooling unit on Fridges.


    yep, and I had 30 amp service in my chieftain and with a decent EMS it ran two ACs as needed.
    bumpy
  • eXodusRV's avatar
    eXodusRV
    Explorer
    Jul 05, 2015
    jerseyjim wrote:
    The only thing 50 AMP does (vs 30 amp) is let you run BOTH a/c units at the same time. Those that say they run 2 units on 30 amps at the same time, are taking a chance with electrical overload and that can equal a fire. Run both on 20AMP? Hope a fire extinguisher is nearby. IMO a definite recipe for disaster. Again...my opinion.
    I have no idea why any coach company would market a unit with 2 a/c units and give 30 amps. IMO (again) that is not only dangerous but stupid. But then, I've seen new units at RV shows with no electrical outlets in the kitchen! How dumb is that?


    You do know what breakers are for ? Do you ?
    In case you use more then 30A then the breaker trips and you will be there without power.

    It's like in your house, you've got probably 5-10 15A outlets wired to the same 20A breaker. How often due houses burn down because of installed wiring ? rarely ever.

    The wiring used for 30A is usually capable to supply double the amps for at least a couple of hours without getting dangerously warm. Most all RVs burn down because of defective cooling unit on Fridges.

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