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dog bone
I have 20 amp service out to my shed and garage. When i plugged my son's trailer into the outside outlet on the side of the garage, that we have used before, the breaker popped. There was nothing on in the trailer or the sheds. We tried a different outlet and it still popped the breaker. We changed the 30 amp breaker in the trailer thinking it might have went bad. Popped again.

We put back the original breaker back in the trailer. I disconnected the wires at the sheds and just put a plug on them. Plugged the trailer into that wire and all was well. Basically i just made an extension cord by disconnecting the sheds.

Prior to all this he did plug into an outlet in the back of the shed and it didn't blow the fuse. He was using an extension cord with out a ground prong on it. He said that when he touched the trailer he got a shock, like tingling shock. Not a knock down one.

I have no problem with running anything in either sheds. Table saw, radial arm saw what ever.

We took his trailer to Pa to see Thomas the Train and plugged into the campgrounds power and had no problem.

I'm thinking there must be some kind of a ground problem because of the tingling, but why doesn't it effect anything else in the sheds. As you can probable tell I am not an electrician, but all I did was go with white to white, black to black and green is ground.

This is not new wiring. It has been out there for at least 5 or 6 years now. We have plugged both of our trailers in before, not at one time, and never had this happen. I am going to get an electrician over and check it out. I was just curious to see what you people can come up with.

John Blue

I think the trailer is OK and not the problem. Look for an open or poor White return ground wire on the outlet. You can check it with a meter. Remove the cover (use care here as it can kill you) and pull outlet out a short ways. Touch one lead on Black wire and other on White wire, you should see around 120 VAC. Now touch Black wire and Green wire, you should see 120 VAC. In your case I think the White wire will have a bad joint and low voltage. Next test is to plug in a drop light for small load. Now run the same test over again and see if this drops the voltage. Remember the wire runs from outlet to outlet and last place to breaker. You need to shut down power and open all outlets in that line up and see if any have a loose wire. The power (Black wire) is flowing back to ground the hard way. It will find a way back like the tingling shock or return back over the Green ground wire. In any case it will be a problem. Other tools and outlets are on different Ckt. and would not be part of this problem. See if this helps.
#1. Neutral/Hot wires reversed on receptacle. A "hot" neutral on a trailer can "energize" the trailer and give that wonderful tingly feeling.
#2. Look for broken insulation on the wires, all the way down and "into" the romex or bx covering. Common spot for this as the wires can be knicked when covering is cut away.
#3. Get a little three light outlet tester, it'll tell you right off what's wrong 99% of the time. Good thing to keep with you and use to check b4 plugging in at a campsite.
dog bone
Thanks guys,
John, We tried a couple of different outlets before I disconnected the sheds with the same result. It wasn't just one outlet. The first outlet in the line that comes from the house still blew the breaker. All the outlets are on the same 20 amp breaker.
If the white was bad wouldn't effect the tools when i plug them in?
John Blue

OK, If a power tool say a drill motor will run then outlet should be good. Part about you ran a drop wire from power panel to trailer and that worked OK tells me you have a fault in the outlets someplace. The power is leaking back to ground in a wire someplace. Information from popup is good, a power leak can run you nuts. I would bet you have a bad joint in a wire and current is leaking to ground. Try this, wire an outlet using romex on floor to power panel and use the same ckt breaker, use three wires, remove old wires first. If this works OK then replace the old romex and all the outlets in that line up.

I found a problem on ground fault ckt that worked but at times would trip off. Someone had pigtailed the Black wire 120 VAC together in a PVC pipe under the ground. Wire joint was good but pvc tape used was leaking current into water inside the PVC pipe. New wire with no joint fixed the problem. They can be a problem to track down at times.
dog bone
I can plug anything into any of the outlets in the sheds and they all work fine. I had to charge up the plow truck last week cause I left the plow controller on. That worked fine. I just plugged in the golf cart to charge the batteries and there was no problem with that. The cart charger was plugged into the outlet that was originally blowing the breaker when the trailer was plugged in. Nothing blew the breaker.

I know it is tough with you guys being there and me here trying to explain to me what could be wrong. I do appreciate you taking the time. I have a tester somewhere in the garage with the three lights in it that popup was talking about. When the wind dies down and it warms up a bit I'll check out the outlets.

If one of the outlets are wired backwards will all the drills and stuff work ok, but because of the circuit panel in the trailer be the reason for blowing the breaker in the house panel? what I am saying if the outlet is wired backward that would change what was powering up the trailers panel. Black would be now going to neutral and white would be hot in the trailer. If it is the problem, why all of a sudden show up now after we have plugged the trailers in before? I have not changed any of the wiring.

I can see where this is going to go. MY best bet is to get an electrician over here and not help him. It would probably be easier for him. I will try the tester and see what happens with that. Thanks again. I'll let you know what I come up with. Winter has moved in good now so no more camping trips this year.
John Blue

The drill motor, golf cart charge, lights, most battery changers will all work as they only use two wires Black and white. The Yellow power tester popup wrote about will pick it up as well. One last item before summer is here. Did you or anyone change or add wiring inside trailer? If so someone may have the Black and White wires rolled over but you said it worked OK at a campground so that rules that out in a way.
dog bone
The only two things that was done to the trailer was to replace the main 30 amp breaker in the trailers panel. Then we put back the original. No wiring was changed. The other was to put in a switch to isolate the battery so there would be no draw while in storage. It was one of those key switches.

I'm going to take the outlet covers off and take a look at the connections. I will shut the power down before i pull the outlets out of their boxes. Turn the power back on then put a meter on the outlets to test as you said. I also have a multimeter in the garage. That is if the 45 to 50 mph winds and snow stop by tomorrow

I'm an iron worker by trade and I would rather be building a bridge or a high rise somewhere rather than mess with screwed up electric.
John Blue

Happy you enjoy the high walking work as it would kill me as soon as I look down. I can take the AC shock better. Good luck on the fix and remember spring is only three more month away.
Another couple of thoughts. Outside outlets are generally protected by a gfci, either a gfci breaker or a gfci receptacle. If it is gfci breaker (usually has a yellow or white button on the breaker along with the switch handle like a typical breaker) Is it the breaker tripping or is it a gfci breaker and the gfci is tripping on the breaker? If not a gfci issue, plug the three light tester in the shed outlet b4 plugging in the camper. Then plug in the camper and see if you can tell which lights go on b4 tripping the breaker. Try plugging it into the outlet that didn't trip the breaker and use the 3 light tester in the camper outlets.
dog bone
Just saw your post popup.

There is no gfci on that circuit. I told John is was going to pull all the covers and inspect visually for a loose wire or a fray, like you said. I have a three light tester and a multimeter also. Just need somebody that can read them correctly. I'm waiting for the snow and wind to die down before i open up outlets outside, little warmer would help also. As I said to John I would rather be building something than playing with electric.
The trailer is in storage now for the winter. All the other stuff seems to work fine. Might just wait til spring.

Thanks to the both of you for your help. I will let you know what I come up with. Bob
I am going to vote for a loose connection in your trailer's cord. That being said, if it is still throwing the breakers at the shed, get an electrician to come out while it is doing it. these things have a tendency to work when repair people look at them and then break when there is no help around. Kind of like noises, rattles and intermittent problems in your car, you always get the $100 diagnostic charge and the "could not duplicate the Problem" diagnosis. A loose wire in your cord (most likely the neutral) would cause the current to return via the ground which on your RV is the chassis. The cord would be positioned differently at the RV park you visited and maybe the wires touched correctly. An electrician is needed if you can't find the problem, because if someone is really well grounded (physically, not emotionally) the tingling feeling may one day become a knockout blow and the Angel Electrictrist will be able to point out where you went wrong from from your new vantage point high above the trailer.
Levi Green
Hey "dog bone",

I have been full timing now (off an' on) since 1994. I have wired many a circuit for my different RVs over the years. I have also rewired two houses, and done quite a bit of electrical work for a private contractor. Having said that, please understand that I am not an electrician ...just a jack of many triads.

Please understand that your shed is wired for twenty amps, and therefore may be wired with 12 gage or [probably] 14 gage wiring. REMEMBER: As the number gets bigger, the wiring gets smaller! This is fine for all of your normal tools.

A thirty amp service takes at least 10 gage wire ...and for a long run I recommend and use 8-3 SO cord (I have a 75 foot 30 amp SO [extension] cord I made in 1994 for just such a purpose). The SO cord looks like a really big (usually black) extension cord, and can handle the great outdoors!

Therefore, I believe your problem is HEAT. Using a 12 or 14 gage wire in your shed probably heated the wiring up somewhere in the shed. You said your RV works fine when camping, so the problem is [probably] not with the RV. Your 30 amp breaker is probably just feeling this and throwing because of the low draw.

Now, think of wiring as a little electron tunnel. Too many electrons flowing over a smaller wire will cause "electron friction" and (after a while) a whole lot of heat (copper melts at 1083.0 C)! All of your normal low amp tools have no problem running, because they are still able to pull enough energy through the now heat degraded wiring in your shed ...and they function properly. This fits everything you have described, including your ability to bypass your shed to power your RV. smile.gif

When you bypassed your shed, you bypassed your current problem (pun intended). huh.gif However, if you continue to use low wattage wiring for your camper will eventually harm your RV, or even start a fire!

NOTE: "Heavy duty" extension cords from Wal*Mart etc. are usually only 12 gage! If you inspect you RV male plug, you will probably notice some (although it may be slight) heat damage. The rubber (or plastic) will melt first and the copper may look kinda pink (it should be shiny gold). This is the usual place where the electron flow is most constricted ...due to the plug. If you see any damage, replace the plug on your RV!

Okay, here is what you need to do from now on. Set up a separate circuit to run you RV from your house's breaker box. Start by putting a 30 amp breaker in there and using at least 10 gage wire in the breaker box (usually two feet of wiring is enough for this project). Then run at least ten gage wiring out to your RV. Everything you need can usually be purchased from The Home Depot or Lowes. (You will probably have to go to an electricians supply store if you want the SO cord.

Again, use at least 10 gage wiring and probably 8 gage wiring for a longer run. Be nice to all of your little electrons (by giving them plenty of room to flow) and they will always be nice to you!

P.S. Make sure your fire insurance policy covers your shed and tools... especially if it is detached!
dog bone
Just a quick up date. The weather in the north east has been terrible. I was finally able to get out and check some wiring. I found 2 plugs that where in pretty bad shape. One of the water proof covers wasn't doing it's job. I replaced both plugs and the water proof covers on both. The plugs in the garage and shed looked to be ok. I have to wait till one of the trailers come back to see if I found the problem.
Levi, both the shed and garage are on a 20 amp designated breaker. 12 gauge wire was used threw out.The only thing that are used when the trailer is plugged in are the trailer light and the reffer just to pack it for a trip. The breaker was popping as soon as the trailer was plugged in. Even when nothing was on not even the converter the breaker blew. Dead short somewhere. The way it was wired it was working fine. Just this last trip in December the problem came up.
I want to thank all of you that came to my aid with your ideas of what could be wrong.. I will let you know more info as I get it. Spring is just around the corner. I hope. Thanks again. Bob
dog bone
Just a quick update. I know that sometimes when you give people some help you don't know if you helped with their problem.
I changed out two exterior outlets. One looked like it was really bad. My son brought up his trailer last Monday and we plugged it in. No blown breakers, everything was fine. I guess one of the two outlets was shorting out. I made a visual check on the rest.
Thanks again for all of your input and suggestions.
Thanks for reporting back.
There are a lot of loads in an RV that are automatically switched on and off. Many of these typically come on just after the power cord is connected such as:

Inverter Charger - 5-12 AMPS
Refrigerator - 2-5 amps
Electric Water Heater - 12 Amps

We don't often think of these loads but they can easily exceed the capacity of a 20 amp circuit. Some of these loads (listed above) start up at the high end of the range and taper off as the batteries charge. Others are intermittent but are all usually ready to start when you first plug in. If these loads combined are over 20 amps, then the 20 amp breaker will "pop".

If an air conditioner is left on or other heavy load, the 20 amp breaker will "pop" as it should.

Most homes have several 15 amp receptacles sharing one 20 amp circuit. So the outlet is over current with sustained loads over 15 AMPS.

If the same circuit in the home has other loads such as tool chargers, lighting etc. these amperages will add to the loads presented by the trailer helping the breaker to "pop".

If you run a dedicated 30 amp circuit for the trailer only, you will eliminate this problem. You will also notice that the #10 wire (or #8 if a long run) is much larger than the #12 or #14 that your house outlets are wired with.
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