shore power

Discussion in 'Class A / Diesel Pushers' started by dastout, Dec 22, 2008.

  1. dastout

    dastout Junior Member

    Just built nice big garage for my 2001 dutchstar and installed a 50 amp outlet so I can plug her up. My question is would it be better to leave power on all the time to the coach or is it better to leave it off except when needed. I would like to leave it on but do not now if some gremlin converter, inverter or pervert would wear out or burn out. The batteries would be kept charged ect,ect. What do ya'll think??
    Thanks folks And Merry Christmas :) ;)
     
  2. Guest

    Guest Guest

    RE: shore power

    I say Leave it plugged in ,, it won't hurt a thing ,, and with u'r rv u prolly have the smart converter/batt. charger ,,,, but one thing ,, do ck u'r battery water level ,, atleast once a month ,,, and add when needed ,, will save alot of hassles later ,,, also put a trickle type charger on u'r engine battery ,, most DO NOT charge when plugged in ,, and ck that battery also for water monthly ,, other than that ,, enjoy u'r new rv garage :approve: :approve: :cool: :bleh:
     
  3. H2H1

    H2H1 Senior Member

    Re: shore power

    Comgrats on the garage, as 730 stated it is ok to keep plugged into shore power. I have a 30 amp outlet and keep mine plugged in. But as 730 mention keep an eye on the water level and add if low , but not just any water will do, you must have distilled water to add to the batteries. Good Luck
     
  4. C Nash

    C Nash Senior Member

    Re: shore power

    Garage sounds great. I leave mine plugged up all the time when home with fridge on. No problem so far and been doing it since 2002 but on the road a lot. Like others I ck the batteries about once a month. Guess the plug it up is ahead so far.
     
  5. miket

    miket New Member

    RE: shore power

    Of course the outlet is 220V -- If it isn't 220, the neutral could carry too much current if it's two legs off the same 120V side of the house breaker box.
     
  6. Grandview Trailer Sa

    Grandview Trailer Sa Senior Member

    Re: shore power

    Maybe I misunderstood, but NOTHING IN AN RV IS 220volts!!!!!!!
     
  7. H2H1

    H2H1 Senior Member

    Re: shore power

    BEAT TO THAT KEN
     
  8. Guest

    Guest Guest

    Re: shore power

    well yes a 50 amp is 220 ,, in a since ,, most have one leg that is 120/30amp carries the coach stuff ,,, the other 120/20amp usally only runs say the a/c if u only have one ,, or maybe even the other stuff that they din't want on the main 30amp circuit ,,, most rv manfacts do it that way ,, splitting the load ,,, all are different ,,, but this is JMO ,,,, and u don't want to know how i wire 30amp rv's to run both a'c units on a 50amp plug :eek: :laugh: :laugh: :laugh:
    I am in no way doupting that a 50amp is a 220 ,, just 2 different breakers ,, usally on 30 amp and one 20amp ,,, not like the single double breaker that is 30amp apiece = 60amps
    I am not trying to start anything ,, and i know there will be others that have their opinion ,, i have no prob with that ,, I'MO ,, and others have theres :approve: :approve: :approve:
     
  9. SnowbirdInFlight

    SnowbirdInFlight Senior Member

    Re: shore power

    Okay, I know I'm just a woman, but even I know that 50 amps is NOT the same as 220 volts. This is a HUGE mistake a lot of RVers make when setting up their electric at their homes. Our dealer said a lot of RVs have been fried because the buyer confused 50 amp service with 220 volt service at their homes. I totally agree with GTS.
     
  10. miket

    miket New Member

    RE: shore power

    First, I never said that there was 220V appliances, but the feed is 220V.

    Second The big mistake is when some one wires a 30 Amp as 220V.

    Third .. A 50 amp coach is supplied by 220V, but the way most coaches are wired, they use the legs as separate 120V legs. The reason is that the two hot leads and the neutral are the same wire guage, and the ground wire is usually a little smaller, since it is not used to carry power. The reason it is 220V is because 220V is 180 degrees out of phase, and the neutral currents cancel so the conductor will only carry 50 amps max, not 100. Both hot legs are 50 amps. You get 3600 Watts power from 30 Amp service, while 50 Amp is 12,000 watts.

    If you wire a RV 50 amp outlet without 220 across the two hot legs, the current in the neutral will exceed 50 amps and cause over heating of the conductor.

    Here is a link that explains it. You need to scroll beyond the 12V stuff -----

    http://www.dasplace.net/RVWiring/wiring.html
     
  11. TexasClodhopper

    TexasClodhopper Senior Member

    RE: shore power



    OK, Mike. So that's what you were talking about! Good info and a great link to it! ;)

    But if there is 'current cancellation' in the neutral, where does that canceled current go?



     
  12. miket

    miket New Member

    RE: shore power

    The currents are 180 degrees out of phase, as the illustration in the link, if both legs have 30 Amp current, the neutral has 0 current, it is canceled out.

    At campgrounds properly wired by qualified electricians, the pedestal has a ganged 50 Amp breaker and 240 V across both hot leads.

    Problems can arise when cheater boxes are used that plug into the 30 Amp and 20 Amp outlets at a pedestal for a 50 Amp rig. The feeds may not be 180 degrees out of phase, but off of the same 120 feed in the panel.

    This 240V is the same as in a house panel. If anyone is familiar with a house panel, there are two feed bars, one neutral and one ground. Ground is for safety and does not carry current unless there is a problem in a device.

    The problem arises when a home electrician wires the 30 Amp RV outlet to 240 because he thinks its a dryer type outlet. This subject has been covered in great detail repetitively at RVNET, and iRV2.

    Google the subject and a lot of info is available.
     
  13. TexasClodhopper

    TexasClodhopper Senior Member

    Re: shore power

    Mike, that's all good information and we all appreciate it, but it doesn't really answer my question.

    Now, if you have two cars driving at each other on a one-lane bridge (they are 180 degrees out-of-phase), and they crash head on, there's a BIG cancellation and a loud boom and a lot of energy dissipated.

    Or, if two people pull against each other with a short rope, each one will eventually get hot and sweaty and wear out and need a beer or a sandwich. The 'cancellation' is visible and sometimes stinks.

    But if currents in a wire are 180 degrees out-of-phase, it is simply said that they "cancel" each other out. Where does that canceled current go? There's no loud bang or anything. Does it reduce the current in the 'hot' leg? Does something get hot when both legs are carrying maximum load? :question:
     
  14. miket

    miket New Member

    Re: shore power

    Ask that to an electrician --- all I know is it cancels and the total current is in the hot legs. Because the wire is properly sized, there is no overheating. Usually 3 conductors of 6 guage and the ground is 8 guage.

    In your car example, isn't going in opposite direction 180 out of phase? Never crash, no bing bang boom----
     
  15. ironart

    ironart New Member

    Re: shore power

    OK.....Here is another thought...

    Remember that the power in a 220V circuit is AC (alternating current) which means that it goes from + to 0 and back to + but 180deg. in reverse.
    Each phase leg is the reverse of the other which means that when one is pushing the other is pulling and visa versa..
    If the power requirement was equal on each leg then there would be no need for the neutral (white) wire. However, things being as they are, the power requirements are different from one phase leg to the other and the difference will go the neutral (white) to complete the circuit. Only the differential current will flow in the neutral wire. If the circuits feeding the 50Amp plug is not a real 220V circuit but just 2 110V circuits in parallel then there will be no current flow from leg 1 to leg 2 because there is NOT a phase reversal. All of the current used from each leg will have to travel in the neutral (white) wire to complete the circuit......This means that the neutral (white) wire will need to be double the size of the hot legs, because it is receiving current from both the hot wires as it tries to provide a path to complete the circuit. This extra flow of electricity will overheat the smaller wire and present a problem.


    Merry Christmas

    Paul
     
  16. C Nash

    C Nash Senior Member

    Re: shore power

    Now I'm scared to even plug mine in :eek: :laugh:
     
  17. miket

    miket New Member

    RE: shore power



    All this just to make sure dastout wired his 50 Amp outlet correctly. If it were wired wrong but the total combined current drawn never exceeds 50 Amps, he's OK, but if it ever went over, the neutral would be overloaded. Plus by code wire size should be 6 guage minimum. If the wire run is of a significant distance, the wire guage needs to be calculated to prevent voltage drop.




    Merry Christmas !!!
     
  18. dastout

    dastout Junior Member

    RE: shore power

    Gee , looks like i stired the pot pretty good with my question about leaving my unit plugged in. Yes I think it is wired correctly, 2 hot legs a neutral and a ground. Wire size is #6 gauge. Coach has been plugged in about a week and all seems fine.

    Happy Holidays to everyone! :approve:
     
  19. miket

    miket New Member

    Re: shore power

    I'm plugged in 24/7/365 with battery minder on chassis battery.


    Hopefully this got the proper info out about true 50 Amp service, that it is 240V, while 30 Amp is 120 at the pedestal.
     
  20. Neal

    Neal New Member

    Re: shore power

    Let me try to explain in a different light.

    If you take two 100 watt light bulbs & wire them in series, then connect them to 220 volts without a neutral, each of the two bulbs will only get 110 volts & will work till one bulb burns out, which will cut the current supply to the second bulb. Remember the Christmas lights that the whole string goes out when one bulb burns out?

    The voltage is dropped to each bulb because is has to receive one leg of it's current through a resistor ( the other bulb).

    Now if you change one of those bulbs to a 60 watt & leave the other one at 100 watt, then the 60 watt bulb will get high voltage & the 100 watt bulb will get low voltage. (They are now drawing through different size resistors.)

    OK, now let us connect a neutral wire at the connection where the two bulbs are connected in series.
    In the case of the two 100 watt bulbs, the neutral wire will carry no current and both bulbs will have 110 volts.
    In the case of the 60 and 100 watt bulb, the neutral wire will carry 40 watts and both bulbs will now have 110 volts each.
    The neutral wire only carries the unbalanced load of the two hot wires from the 220 volt leads.

    This is the way almost all residences are wired at the main panel. 220 volt service with the neutral only carrying the unbalanced load from the total house. If you could keep the load balanced at all time, you probably would not even need a neutral but some joker would always want to flip on another light, which would throw the load out of balance.
     

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