# Electrical issue



## luukoutbelow (Jan 11, 2007)

'89 Class C Minnie Winnie

Plugged into a house using 12 gauge cord.  Microwave blows breaker in house almost everytime we try to run it, even if only a few other things are running (1light and a small space heater).  I believe we have a 30 amp system on there.  Any ideas about how to troubleshoot this.  Short circuit in microwave maybe?  Does it have anything to do with the extention cord being 15 amp.  Please bear with me,  I suck at electrical work.

Thanks, 
Hunter :laugh:


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## Grandview Trailer Sa (Jan 11, 2007)

Re: Electrical issue

You are overloading the breaker in the house.  Your trailer is 30 amps, but what are you plugged into from the house?  That is what controls what you can do in the trailer.  A microwave will pull about 12 amps, and anything else will put you over the 15 amp. edge.  If your cord is rated for 15 amps, you are overloading that also.


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## C Nash (Jan 11, 2007)

Re: Electrical issue

How long is the cord. You will not be able to run the microwave and a small heater using a 12 guage cord IMO.  Don't try it.


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## luukoutbelow (Jan 11, 2007)

Re: Electrical issue

Its a 25' cord.  Would replacing that with a 30 amp cord do the trick or is the house or the connector to the house the limiting factor here?  Any suggestions or solutions to this?

Thanks


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## C Nash (Jan 11, 2007)

Re: Electrical issue

If the breaker in the house is a 15 amp it will trip using the microwave and heater. You said it was 30 but, I was assuming you meant the rv had 30 amp service.


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## luukoutbelow (Jan 11, 2007)

Re: Electrical issue

Yeah, I think the RV is a 30 amp.  Well that still answers my question though.  Guess we'll have to make do for the mean time.  Thanks for the help.


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## Kirk (Jan 11, 2007)

Re: Electrical issue

It does not matter that the breaker for the RV is 30a because the smallest rated breaker is always the one in control. When you plug into the house that breaker is only rated for 15A and that is always going to be the limit, no matter what you do. A long extension cord can be the cause of voltage problems, but it has nothing to do with the breaker tripping. When you plug in to shore power, the 120V-ac to 12V-dc converter is always on and it will always draw some power to supply any charge needed for the batteries, to operate the control circuit boards for the refrigerator, water heater, furnace and such and that along with the 12A or so that the microwave draws will exceed the 15A limit of the standard house circuit breaker. The only way to correct that problem is to have a new, 120V-30A outlet installed that would also be supplied by a 30A circuit breaker and plug the RV into that.


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## TexasClodhopper (Jan 12, 2007)

Re: Electrical issue

Dang gummit, Kirk!  I was just fixin' to say that!  

Circuit breakers don't care how long (or smaller) your cords are.  The appliances/motors at the end of the cord (in your MH) might draw more current, because a longer (or smaller) cord will reduce the available voltage at the MH end.

The longer (or smaller) the cord; the more resistance it has.  The more current you try to draw through it from the MH end; the more voltage the cord develops across the length of the cord.  This voltage is no longer availble for the MH to use.  If you start out with 110 volts at the house/park connection, and you lose 10 volts across a long (or small) cord, then you end up with 100 volts at the MH.  Turn another appliance on; cause another 5 volt drop across the cord; and you end up with 95 volts at the MH.

If the appliance you turn on is a motor (inductive) load, it probably draws more current at lower voltages than at higher voltages.  So, there is an exponential (non-linear) rise in current when the available voltage gets down below 100 volts.

Having said all this, it doesn't mean that if you find a cord that is 2 inches in diameter that all your problems are over!  There is a point where the cord is not a big enough factor to even calculate its effect.

The circuit breaker in your house/park connection could also just be weak.


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## hertig (Jan 12, 2007)

Re: Electrical issue

Also, is it a GFI outlet or connected to a GFI outlet or breaker?  I visited a friend's house, and his outside GFI always tripped with 'nothing' on except for things like the converter which are always on.  Plugged it into the outlet on his garage door opener, and no more problems.  

How much does that space heater draw?  That is what might be overloading the circuit in concert with the microwave.

I used to run my 30 amp trailer from a 15 amp outlet without problems as long as I only had '1' big draw item going at a time (AC, microwave, vacuum cleaner, electric heater or the like).  When I upgraded to a 50 amp RV, I went ahead and put in a 50 amp outlet to power it.  Also put in some 20 amp outlets for Christmas lights, as the 50 amp breaker had 2 20 amp breakers in it too.

Best thing would be to use a 30A extention cord and then put it through the 30A to 15A adapter ('dog bone') right at the outlet.  I did use a 50' 15A extention cord on occasion without problems, but it was 10 ga.


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## luukoutbelow (Jan 12, 2007)

Re: Electrical issue

First of all, thanks for all of the replys.  You guys are great!  Hertig, how much did it cost you to install the 50 amp outlet with the works?  I think that is what we're going to do, but is it still safe for my truck?  Again, Im not the electrical guru and I just want to be on the same page.  With the 50 amp system installed with a 30-50 amp adapter, am I still risking things with a possible low voltage condition?  We could put that breaker pretty close to the truck.  What would the ideal situation be?  Im parked right next to a house.  What would you do if you were me?  Thanks again for all of the great advise and help.

Hunter


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## Grandview Trailer Sa (Jan 12, 2007)

Re: Electrical issue

I wired a 30 amp outlet on the side of my house with a 30 amp breaker in the box.  I reduce my 50 amp trailer and plug in just like in a campground.  Mostly I keep the refer going and batteries charged.  I know I don't need 30 amps to do that, but I can do what I need in the trailer.


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## ARCHER (Jan 13, 2007)

Re: Electrical issue

That is exactly what I want to do when I get back home this spring.  Wire (10 gage) a 30 amp circuit breaker inside the house and run the line outside and hook up  like at a campground.  I'm gonna put in a regular plug also so I can use the line for plugging in electrical garden tools.  Been wanting to do this for five years, so guess it is time.  I kept popping GFCI breaker (on a 15 amp breaker) on patio when I plugged in Class A electrical line, even with only fridge, converter operating.


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## TexasClodhopper (Jan 13, 2007)

Re: Electrical issue

OK, Archer.  We're going to be waiting for a picture of that this spring.  

Gotta keep you pumped up.  

It ain't that hard.  YOU CAN DO IT!  

What's the plan?  How do you have it figgered?


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## ARCHER (Jan 13, 2007)

Re: Electrical issue

OK, I'll just do that and send in a picture.  Plan is simple, I think.  Put in new 30 amp circuit breaker at main panel, run 10 gage wire out to where I park the ole gal (in conduit), then hook up RV type plug, and regular plug (gfci type).  Will put that on a 4x4 post near rear of MH parking area.  Sure hope Momma can get this all done.....  :laugh:


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## TexasClodhopper (Jan 13, 2007)

Re: Electrical issue

If Momma is doing it, then you might as well run water/sewer out there, too. (You might be staying in it!  )

And don't forget the night light!


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## hertig (Jan 13, 2007)

Re: Electrical issue

lets see, maybe $20 for the breaker and $40 for the box and $30 for the wire.  $100 all told, but I did the work myself, and that does not include the right angle drill to drill down through the top plate of the wall of the house.  I mounted my outlet box on the wall of the house near where I park the RV.  Nice, because that's the room the main breaker panel is in, so not much of a wire run.  Note that this is 50 amps, dual polarity, with 2 20 amp circuits, so a single polarity 30 amp setup should be rather cheaper.

Note that wire size is critical to avoid fires.  You need to know the current AND the distance to ensure you use the appropriate wire.  Also the appropriate type of wire and/or conduit depending on whether you are in a wall, exposed or under ground.  Make sure your service will support this new large draw.  I was originally only 100 amps, which would not have supported the new circuits.  But I upgraded to 200 amps when I put in air conditioning, so it handles it fine.

If you don't know what you are doing, it is worth the effort to either learn, or hire someone who knows.  Wrong wiring can burn down your house or kill someone.  The hairiest part is installing the breaker.  I'm too chicken to work in there with full power exposed like that, but fortunately I have an external main breaker so was able to completely kill the breaker panel when installing the breaker.    

My suggestion is to put in 50 amps if you can.  A bit more money, but can be easily converted to 30 amps.  But if you put in 30 amps, you will need to completely redo it if you ever need to go to 50 amps.  If you never will upgrade to a 50 amp RV or never will use more than 30 amps, then its probably not worth the extra.  However, I use my RV as a 'guest house' and run the AC and that requires more than 30 amps.

I would suggest NOT putting 15 amp outlets in this circuit unless they are separately fused at 15 amps, either in the RV outlet box or from a separate breaker in the main box, with separate wire.  This is because if you plug something into a 15 amp socket powered by a 50 or 30 amp breaker, then if there is a problem, something from the socket outwards is going to burn.


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## jwestbrook (Jan 13, 2007)

RE: Electrical issue

hey im an electrician. your microwave shouldnt trip a breaker alone. what amp breaker r u on. that space heater may pull a pretty good load and how long is your 12 gauge cord. the longer the cord, the more voltage drop youll have which increases amperage....maybe try another circuit or a shorter cord.....but yeah you need a 10 gauge cord if possible.....microwave pull a lot, electrical code requires them to be on there own circuit in houses if that tells you anything.


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## TexasClodhopper (Jan 13, 2007)

Re: Electrical issue

A longer cord won't make a "space heater" draw more amperage.  "Space heaters" are usually resistive loads.  Some inductive loads will draw more current at lower voltages than design.


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